Consistency in infants' behavioural signalling of satiation during bottle-feeding.

Related Articles

Consistency in infants' behavioural signalling of satiation during bottle-feeding.

Pediatr Obes. 2015 Jun;10(3):180-7

Authors: Ventura AK, Inamdar LB, Mennella JA

Abstract
BACKGROUND: Understanding the dynamics of feeding is essential for preventing accelerated weight gain during infancy, a risk factor for obesity.
OBJECTIVES: Because infants satiate on larger volumes of cow milk formula (CMF) than CMF enriched with the free amino acid glutamate (CMF + glu), we used this model system to determine whether infants displayed consistent behaviours despite satiating on lower volumes.
METHODS: In this laboratory-based, within-subject experimental study of ≤4-month-old infants (n = 41) and their mothers, infants were videotaped while feeding to satiation CMF on one test day and CMF + glu on the other, in counterbalanced order. Each video-recording was analysed frame-by-frame for frequency and timing of behaviours.
RESULTS: Infants' behaviours were consistent in types and frequency but were displayed sooner when feeding CMF + glu compared with CMF. The less responsive the mother's feeding style, the less consistent the infant displayed behaviours across the two formula meals (P = 0.05). Infants who spat up (a possible sign of overfeeding) consumed more formula (P = 0.01) and had less responsive mothers (P = 0.04) compared with the other infants.
CONCLUSIONS: Infants are consistent in their behavioural displays during feeding at this developmental age. Regulation of intake and signalling of satiation during bottle-feeding are associated with formula composition and maternal feeding style.

PMID: 24990443 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1Wf1Iwq

Consistency in infants' behavioural signalling of satiation during bottle-feeding.

Related Articles

Consistency in infants' behavioural signalling of satiation during bottle-feeding.

Pediatr Obes. 2015 Jun;10(3):180-7

Authors: Ventura AK, Inamdar LB, Mennella JA

Abstract
BACKGROUND: Understanding the dynamics of feeding is essential for preventing accelerated weight gain during infancy, a risk factor for obesity.
OBJECTIVES: Because infants satiate on larger volumes of cow milk formula (CMF) than CMF enriched with the free amino acid glutamate (CMF + glu), we used this model system to determine whether infants displayed consistent behaviours despite satiating on lower volumes.
METHODS: In this laboratory-based, within-subject experimental study of ≤4-month-old infants (n = 41) and their mothers, infants were videotaped while feeding to satiation CMF on one test day and CMF + glu on the other, in counterbalanced order. Each video-recording was analysed frame-by-frame for frequency and timing of behaviours.
RESULTS: Infants' behaviours were consistent in types and frequency but were displayed sooner when feeding CMF + glu compared with CMF. The less responsive the mother's feeding style, the less consistent the infant displayed behaviours across the two formula meals (P = 0.05). Infants who spat up (a possible sign of overfeeding) consumed more formula (P = 0.01) and had less responsive mothers (P = 0.04) compared with the other infants.
CONCLUSIONS: Infants are consistent in their behavioural displays during feeding at this developmental age. Regulation of intake and signalling of satiation during bottle-feeding are associated with formula composition and maternal feeding style.

PMID: 24990443 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1Wf1Iwq

Global RNA Fold and Molecular Recognition for a pfl Riboswitch Bound to ZMP, a Master Regulator of One-Carbon Metabolism.

Related Articles

Global RNA Fold and Molecular Recognition for a pfl Riboswitch Bound to ZMP, a Master Regulator of One-Carbon Metabolism.

Structure. 2015 Aug 4;23(8):1375-81

Authors: Ren A, Rajashankar KR, Patel DJ

Abstract
ZTP, the pyrophosphorylated analog of ZMP (5-amino-4-imidazole carboxamide ribose-5'-monophosphate), was identified as an alarmone that senses 10-formyl-tetrahydroflate deficiency in bacteria. Recently, a pfl riboswitch was identified that selectively binds ZMP and regulates genes associated with purine biosynthesis and one-carbon metabolism. We report on the structure of the ZMP-bound Thermosinus carboxydivorans pfl riboswitch sensing domain, thereby defining the pseudoknot-based tertiary RNA fold, the binding-pocket architecture, and principles underlying ligand recognition specificity. Molecular recognition involves shape complementarity, with the ZMP 5-amino and carboxamide groups paired with the Watson-Crick edge of an invariant uracil, and the imidazole ring sandwiched between guanines, while the sugar hydroxyls form intermolecular hydrogen bond contacts. The burial of the ZMP base and ribose moieties, together with unanticipated coordination of the carboxamide by Mg(2+), contrasts with exposure of the 5'-phosphate to solvent. Our studies highlight the principles underlying RNA-based recognition of ZMP, a master regulator of one-carbon metabolism.

PMID: 26118534 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/25eJ7G2

Global RNA Fold and Molecular Recognition for a pfl Riboswitch Bound to ZMP, a Master Regulator of One-Carbon Metabolism.

Related Articles

Global RNA Fold and Molecular Recognition for a pfl Riboswitch Bound to ZMP, a Master Regulator of One-Carbon Metabolism.

Structure. 2015 Aug 4;23(8):1375-81

Authors: Ren A, Rajashankar KR, Patel DJ

Abstract
ZTP, the pyrophosphorylated analog of ZMP (5-amino-4-imidazole carboxamide ribose-5'-monophosphate), was identified as an alarmone that senses 10-formyl-tetrahydroflate deficiency in bacteria. Recently, a pfl riboswitch was identified that selectively binds ZMP and regulates genes associated with purine biosynthesis and one-carbon metabolism. We report on the structure of the ZMP-bound Thermosinus carboxydivorans pfl riboswitch sensing domain, thereby defining the pseudoknot-based tertiary RNA fold, the binding-pocket architecture, and principles underlying ligand recognition specificity. Molecular recognition involves shape complementarity, with the ZMP 5-amino and carboxamide groups paired with the Watson-Crick edge of an invariant uracil, and the imidazole ring sandwiched between guanines, while the sugar hydroxyls form intermolecular hydrogen bond contacts. The burial of the ZMP base and ribose moieties, together with unanticipated coordination of the carboxamide by Mg(2+), contrasts with exposure of the 5'-phosphate to solvent. Our studies highlight the principles underlying RNA-based recognition of ZMP, a master regulator of one-carbon metabolism.

PMID: 26118534 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/25eJ7G2

The development of sweet taste: From biology to hedonics.

The development of sweet taste: From biology to hedonics.

Rev Endocr Metab Disord. 2016 May 19;

Authors: Mennella JA, Bobowski NK, Reed DR

Abstract
From the age of 2 years, an American child is more likely to consume a sugar-sweetened product than a fruit or vegetable on any given day-a troubling statistic, given that food preferences are established early in childhood, as well as the strong association between this dietary pattern and increased risk of developing a number of chronic diseases. Here, we review the ontogeny and biopsychology of sweet taste, highlighting how a biological drive to prefer sweetness at high concentrations during childhood, which would have conferred an advantage in environments of scarcity, now predisposes children to overconsume all that is sweet in a modern food system replete with added sugars. We review the power of sweet taste to blunt expressions of pain and mask bad tastes in foods as well as factors that predispose some to consume high-sugar diets, including experiential learning and taste preferences driven in part by genetics. Understanding children's unique vulnerability to our current food environment, rich in both nutritive and nonnutritive sweeteners, is highlighted as a priority for future research to develop evidence-based strategies to help establish healthy dietary behaviors early in life.

PMID: 27193110 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1U4jAna

The development of sweet taste: From biology to hedonics.

The development of sweet taste: From biology to hedonics.

Rev Endocr Metab Disord. 2016 May 19;

Authors: Mennella JA, Bobowski NK, Reed DR

Abstract
From the age of 2 years, an American child is more likely to consume a sugar-sweetened product than a fruit or vegetable on any given day-a troubling statistic, given that food preferences are established early in childhood, as well as the strong association between this dietary pattern and increased risk of developing a number of chronic diseases. Here, we review the ontogeny and biopsychology of sweet taste, highlighting how a biological drive to prefer sweetness at high concentrations during childhood, which would have conferred an advantage in environments of scarcity, now predisposes children to overconsume all that is sweet in a modern food system replete with added sugars. We review the power of sweet taste to blunt expressions of pain and mask bad tastes in foods as well as factors that predispose some to consume high-sugar diets, including experiential learning and taste preferences driven in part by genetics. Understanding children's unique vulnerability to our current food environment, rich in both nutritive and nonnutritive sweeteners, is highlighted as a priority for future research to develop evidence-based strategies to help establish healthy dietary behaviors early in life.

PMID: 27193110 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1U4jAna

The development of sweet taste: From biology to hedonics.

The development of sweet taste: From biology to hedonics.

Rev Endocr Metab Disord. 2016 May 19;

Authors: Mennella JA, Bobowski NK, Reed DR

Abstract
From the age of 2 years, an American child is more likely to consume a sugar-sweetened product than a fruit or vegetable on any given day-a troubling statistic, given that food preferences are established early in childhood, as well as the strong association between this dietary pattern and increased risk of developing a number of chronic diseases. Here, we review the ontogeny and biopsychology of sweet taste, highlighting how a biological drive to prefer sweetness at high concentrations during childhood, which would have conferred an advantage in environments of scarcity, now predisposes children to overconsume all that is sweet in a modern food system replete with added sugars. We review the power of sweet taste to blunt expressions of pain and mask bad tastes in foods as well as factors that predispose some to consume high-sugar diets, including experiential learning and taste preferences driven in part by genetics. Understanding children's unique vulnerability to our current food environment, rich in both nutritive and nonnutritive sweeteners, is highlighted as a priority for future research to develop evidence-based strategies to help establish healthy dietary behaviors early in life.

PMID: 27193110 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1U4jAna

A Neural Mechanism of Taste Perception Modulated by Odor Information.

A Neural Mechanism of Taste Perception Modulated by Odor Information.

Chem Senses. 2016 May 12;

Authors: Shimemura T, Fujita K, Kashimori Y

Abstract
Taste perception is significantly affected by other sensory modalities such as vision, smell, and somatosensation. Such taste sensation elicited by integrating gustatory and other sensory information is referred to as flavor. Although experimental studies have demonstrated the characteristics of flavor perception influenced by other sensory modalities and the involved brain areas, it remains unknown how flavor emerges from the brain circuits. Of the involved brain areas, orbitofrontal cortex (OFC), as well as gustatory cortex (GC), plays a dominant role in flavor perception. We develop here a neural model of gustatory system which consists of GC and OFC networks and examine the neural mechanism of odor-induced taste perception. Using the model, we show that flavor perception is shaped by experience-dependent learning of foods with congruent taste-odor pairs, providing a unique representation of flavor through the interaction between OFC and GC neurons. Our model also shows that feedback signals from OFC to GC modulate the dynamic stability of taste attractors in GC, leading to the enhancement or suppression of taste responses by smells. Furthermore, modeling shows that spatial variability in GC activity evoked by tastants determines to what extent odor enhances congruent taste responses. The results suggest that flavor perception is deeply associated with dynamic stability of GC attractors through the interaction between GC and OFC.

PMID: 27178285 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XbS4JT

A Neural Mechanism of Taste Perception Modulated by Odor Information.

A Neural Mechanism of Taste Perception Modulated by Odor Information.

Chem Senses. 2016 May 12;

Authors: Shimemura T, Fujita K, Kashimori Y

Abstract
Taste perception is significantly affected by other sensory modalities such as vision, smell, and somatosensation. Such taste sensation elicited by integrating gustatory and other sensory information is referred to as flavor. Although experimental studies have demonstrated the characteristics of flavor perception influenced by other sensory modalities and the involved brain areas, it remains unknown how flavor emerges from the brain circuits. Of the involved brain areas, orbitofrontal cortex (OFC), as well as gustatory cortex (GC), plays a dominant role in flavor perception. We develop here a neural model of gustatory system which consists of GC and OFC networks and examine the neural mechanism of odor-induced taste perception. Using the model, we show that flavor perception is shaped by experience-dependent learning of foods with congruent taste-odor pairs, providing a unique representation of flavor through the interaction between OFC and GC neurons. Our model also shows that feedback signals from OFC to GC modulate the dynamic stability of taste attractors in GC, leading to the enhancement or suppression of taste responses by smells. Furthermore, modeling shows that spatial variability in GC activity evoked by tastants determines to what extent odor enhances congruent taste responses. The results suggest that flavor perception is deeply associated with dynamic stability of GC attractors through the interaction between GC and OFC.

PMID: 27178285 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XbS4JT

A Neural Mechanism of Taste Perception Modulated by Odor Information.

A Neural Mechanism of Taste Perception Modulated by Odor Information.

Chem Senses. 2016 May 12;

Authors: Shimemura T, Fujita K, Kashimori Y

Abstract
Taste perception is significantly affected by other sensory modalities such as vision, smell, and somatosensation. Such taste sensation elicited by integrating gustatory and other sensory information is referred to as flavor. Although experimental studies have demonstrated the characteristics of flavor perception influenced by other sensory modalities and the involved brain areas, it remains unknown how flavor emerges from the brain circuits. Of the involved brain areas, orbitofrontal cortex (OFC), as well as gustatory cortex (GC), plays a dominant role in flavor perception. We develop here a neural model of gustatory system which consists of GC and OFC networks and examine the neural mechanism of odor-induced taste perception. Using the model, we show that flavor perception is shaped by experience-dependent learning of foods with congruent taste-odor pairs, providing a unique representation of flavor through the interaction between OFC and GC neurons. Our model also shows that feedback signals from OFC to GC modulate the dynamic stability of taste attractors in GC, leading to the enhancement or suppression of taste responses by smells. Furthermore, modeling shows that spatial variability in GC activity evoked by tastants determines to what extent odor enhances congruent taste responses. The results suggest that flavor perception is deeply associated with dynamic stability of GC attractors through the interaction between GC and OFC.

PMID: 27178285 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1XbS4JT

Why do we like sweet taste: A bitter tale?

Why do we like sweet taste: A bitter tale?

Physiol Behav. 2016 May 9;

Authors: Beauchamp GK

Abstract
Sweet is widely considered to be one of a small number of basic or primary taste qualities. Liking for sweet tasting substances is innate, although postnatal experiences can shape responses. The power of sweet taste to induce consumption and to motivate behavior is profound, suggesting the importance of this sense for many species. Most investigators presume that the ability to identify sweet molecules through the sense of taste evolved to allow organisms to detect sources of readily available glucose from plants. Perhaps the best evidence supporting this presumption are recent discoveries in comparative biology demonstrating that species in the order Carnivora that do not consume plants also do not perceive sweet taste due to the pseudogenization of a component of the primary sweet taste receptor. However, arguing against this idea is the observation that the sweetness of a plant, or the amount of easily metabolizable sugars contained in the plant, provides little quantitative indication of the plant's energy or broadly conceived food value. Here it is suggested that the perceptual ratio of sweet taste to bitter taste (a signal for toxicity) may be a better gauge of a plant's broadly conceived food value than sweetness alone and that it is this ratio that helps guide selection or rejection of a potential plant food.

PMID: 27174610 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhPpS

The Association Between Olfaction and Depression: A Systematic Review.

The Association Between Olfaction and Depression: A Systematic Review.

Chem Senses. 2016 May 11;

Authors: Kohli P, Soler ZM, Nguyen SA, Muus JS, Schlosser RJ

Abstract
Previous studies on the relationship between olfaction and depression have revealed mixed results. In addition, few have focused on the reciprocity of this association. The aim of this study is to combine depression and olfactory data in two separate patient populations to further understand their association. A systematic literature review was conducted using 3 online databases to identify studies correlating olfaction and depression in patients presenting with either primary depression or primary olfactory dysfunction. For the depressed population, weighted means and standard deviations for the Sniffin' Sticks Test and the 40-item Smell Identification Test were combined using 10 studies. For the olfactory dysfunction population, weighted means of Beck's Depression Inventory were combined using 3 studies. Independent t-tests were used to compare differences between groups. Comparing primary depressed patients with controls, depressed patients showed decreased scores in olfactory threshold (6.31±1.38 vs. 6.78±0.88, P = 0.0005), discrimination (12.05±1.44 vs. 12.66±1.36, P = 0.0073), identification (12.57±0.74 vs. 12.98±0.90, P < 0.0001), and 40-Item Smell Identification Test (35.31±1.91 vs. 37.41±1.45, P < 0.0001). In patients with primary olfactory dysfunction, Beck's Depression Inventory scores were significantly different between patients classified as normosmics, hyposmics and anosmics (5.21±4.73 vs. 10.93±9.25 vs. 14.15±5.39, P ≤ 0.0274 for all 3 comparisons). In conclusion, patients with depression have reduced olfactory performance when compared with the healthy controls and conversely, patients with olfactory dysfunction, have symptoms of depression that worsen with severity of smell loss.

PMID: 27170667 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3VbW

Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS).

Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS).

Chem Senses. 2016 May 11;

Authors: Hoffmann-Hensel SM, Freiherr J

Abstract
Priming describes the principle of modified stimulus perception that occurs due to a previously presented stimulus. Although we have begun to understand the mechanisms of crossmodal priming, the concept of intramodal olfactory priming remains relatively unexplored. Therefore, we applied positive and negative odors using respiration-triggered olfactory stimulation (RETROS), enabling us to record the skin conductance response (SCR) and breathing data without a crossmodal cueing error and measure reaction times (RTs) for olfactory tasks. RT, SCR, and breathing data revealed that negative odors were perceived significantly more arousing than positive ones. In a second experiment, 2 odors were applied during consecutive respirations. Here, we observed intramodal olfactory priming effects: A negative odor preceded by a positive odor was rated as more pleasant than when the same odor was preceded by a negative odor. Additionally, a longer identification RT was found for the second compared with the first odor. We interpret this as increased "perceptual load" due to incomplete first odor processing while the second odor was presented. Furthermore, intramodal priming can be considered a possible reason for the increase of identification RT. The use of RETROS led to these novel insights into olfactory processing beyond crossmodal interaction by providing a noncued unimodal olfactory test, and therefore, RETROS can be used in the experimental design of future olfactory studies.

PMID: 27170666 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhTWs

A Drosophila Gustatory Receptor Required for Strychnine Sensation.

Related Articles

A Drosophila Gustatory Receptor Required for Strychnine Sensation.

Chem Senses. 2015 Sep;40(7):525-33

Authors: Lee Y, Moon SJ, Wang Y, Montell C

Abstract
Strychnine is a potent, naturally occurring neurotoxin that effectively protects plants from animal pests by deterring feeding behavior. In insects, such as the fruit fly, Drosophila melanogaster, bitter-tasting aversive compounds are detected primarily through a family of gustatory receptors (GRs), which are expressed in gustatory receptor neurons. We previously described multiple GRs that eliminate the behavioral avoidance to all bitter compounds tested, with the exception of strychnine. Here, we report the identity of a strychnine receptor, referred to as GR47a. We generated a mutation in Gr47a and found that it eliminated strychnine repulsion and strychnine-induced action potentials. GR47a was narrowly tuned, as the responses to other avoidance compounds were unaffected in the mutant animals. This analysis supports an emerging model that Drosophila GRs fall broadly into two specificity classes-one class is comprised of core receptors that are broadly required, whereas the other class, which includes GR47a, consists of narrowly tuned receptors that define chemical specificity.

PMID: 26187906 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3QEX

Oleogustus: The Unique Taste of Fat.

Related Articles

Oleogustus: The Unique Taste of Fat.

Chem Senses. 2015 Sep;40(7):507-16

Authors: Running CA, Craig BA, Mattes RD

Abstract
Considerable mechanistic data indicate there may be a sixth basic taste: fat. However, evidence demonstrating that the sensation of nonesterified fatty acids (NEFA, the proposed stimuli for "fat taste") differs qualitatively from other tastes is lacking. Using perceptual mapping, we demonstrate that medium and long-chain NEFA have a taste sensation that is distinct from other basic tastes (sweet, sour, salty, and bitter). Although some overlap was observed between these NEFA and umami taste, this overlap is likely due to unfamiliarity with umami sensations rather than true similarity. Shorter chain fatty acids stimulate a sensation similar to sour, but as chain length increases this sensation changes. Fat taste oral signaling, and the different signals caused by different alkyl chain lengths, may hold implications for food product development, clinical practice, and public health policy.

PMID: 26142421 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhLGE

Oleogustus: The Unique Taste of Fat.

Related Articles

Oleogustus: The Unique Taste of Fat.

Chem Senses. 2015 Sep;40(7):507-16

Authors: Running CA, Craig BA, Mattes RD

Abstract
Considerable mechanistic data indicate there may be a sixth basic taste: fat. However, evidence demonstrating that the sensation of nonesterified fatty acids (NEFA, the proposed stimuli for "fat taste") differs qualitatively from other tastes is lacking. Using perceptual mapping, we demonstrate that medium and long-chain NEFA have a taste sensation that is distinct from other basic tastes (sweet, sour, salty, and bitter). Although some overlap was observed between these NEFA and umami taste, this overlap is likely due to unfamiliarity with umami sensations rather than true similarity. Shorter chain fatty acids stimulate a sensation similar to sour, but as chain length increases this sensation changes. Fat taste oral signaling, and the different signals caused by different alkyl chain lengths, may hold implications for food product development, clinical practice, and public health policy.

PMID: 26142421 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhLGE

Odor Emotional Quality Predicts Odor Identification.

Related Articles

Odor Emotional Quality Predicts Odor Identification.

Chem Senses. 2015 Sep;40(7):517-23

Authors: Bestgen AK, Schulze P, Kuchinke L

Abstract
It is commonly agreed upon a strong link between emotion and olfaction. Odor-evoked memories are experienced as more emotional compared with verbal, visual, and tactile stimuli. Moreover, the emotional quality of odor cues increases memory performance, but contrary to this, odors are poor retrieval cues for verbal labels. To examine the relation between the emotional quality of an odor and its likelihood of identification, this study evaluates how normative emotion ratings based on the 3-dimensional affective space model (that includes valence, arousal, and dominance), using the Self-Assessment Manikin by Bradley and Lang (Bradley MM, Lang PJ. 1994. Measuring emotion: the Self-Assessment Manikin and the Semantic Differential. J Behav Ther Exp Psychiatry. 25(1):49-59.) and the Positive and Negative Affect Schedule (Watson D, Clark LA, Tellegen A. 1988. Development and validation of brief measures of positive and negative affect: the PANAS scales. J Pers Soc Psychol. 54(6):1063-1070.) predict the identification of odors in a multiple choice condition. The best fitting logistic regression model includes squared valence and dominance and thus, points to a significant role of specific emotional features of odors as a main clue for odor identification.

PMID: 26142420 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3QFc

Mice Lacking Pannexin 1 Release ATP and Respond Normally to All Taste Qualities.

Related Articles

Mice Lacking Pannexin 1 Release ATP and Respond Normally to All Taste Qualities.

Chem Senses. 2015 Sep;40(7):461-7

Authors: Vandenbeuch A, Anderson CB, Kinnamon SC

Abstract
Adenosine triphosphate (ATP) is required for the transmission of all taste qualities from taste cells to afferent nerve fibers. ATP is released from Type II taste cells by a nonvesicular mechanism and activates purinergic receptors containing P2X2 and P2X3 on nerve fibers. Several ATP release channels are expressed in taste cells including CALHM1, Pannexin 1, Connexin 30, and Connexin 43, but whether all are involved in ATP release is not clear. We have used a global Pannexin 1 knock out (Panx1 KO) mouse in a series of in vitro and in vivo experiments. Our results confirm that Panx1 channels are absent in taste buds of the knockout mice and that other known ATP release channels are not upregulated. Using a luciferin/luciferase assay, we show that circumvallate taste buds from Panx1 KO mice normally release ATP upon taste stimulation compared with wild type (WT) mice. Gustatory nerve recordings in response to various tastants applied to the tongue and brief-access behavioral testing with SC45647 also show no difference between Panx1 KO and WT. These results confirm that Panx1 is not required for the taste evoked release of ATP or for neural and behavioral responses to taste stimuli.

PMID: 26136251 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhWS8

Enhancement of Odor Sensitivity Following Repeated Odor and Visual Fear Conditioning.

Related Articles

Enhancement of Odor Sensitivity Following Repeated Odor and Visual Fear Conditioning.

Chem Senses. 2015 Sep;40(7):497-506

Authors: Parma V, Ferraro S, Miller SS, Åhs F, Lundström JN

Abstract
Odor detection sensitivity can be rapidly altered by fear conditioning; whether this effect is augmented over time is not known. The present study aimed to test whether repeated conditioning sessions induce changes in odor detection threshold as well as in conditioned responses and whether olfactory stimuli evoke stronger conditioned responses than visual stimuli. The repeated conditioning group participated in repeated sessions over 2 weeks whereas the single conditioning group participated in 1 conditioning session; both groups were presented with visual and olfactory stimuli, were paired with an electric shock (CS+) and 2 matched control stimuli not paired with shock (CS-) while olfactory detection threshold and skin conductance responses (SCRs) were measured before and after the last session. We found increased sensitivity for the CS+ odor in the repeated but not in the single conditioning group, consistent with changes in olfactory sensitivity following repeated aversive learning and of a similar magnitude to what has previously been demonstrated in the periphery. SCR to the visual and olfactory CS+ were similar between groups, indicating that sensory thresholds can change without corresponding change in conditioned responses. In conclusion, repeated conditioning increases detection sensitivity and reduces conditioned responses, suggesting that segregated processes influence perception and conditioned responses.

PMID: 26126729 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3VIS

Olfactory Discrimination Learning in an Outbred and an Inbred Strain of Mice.

Related Articles

Olfactory Discrimination Learning in an Outbred and an Inbred Strain of Mice.

Chem Senses. 2015 Sep;40(7):489-96

Authors: Laska M

Abstract
The present study compared olfactory discrimination learning in CD-1 mice, a widely used outbred strain of mice with that of C57BL/6J mice, one of the most widely used inbred mouse strains. Using an automated olfactometer and a standard operant conditioning procedure, I found that CD-1 mice needed 60 trials to reach learning criterion in an initial 2-odor discrimination task. They improved in learning speed in subsequent discrimination tasks in which either the rewarded or the unrewarded stimulus was replaced for a new stimulus. C57BL/6J mice, in contrast, needed 120 trials to reach learning criterion in an initial 2-odor discrimination task and also needed significantly more trials than the CD-1 mice in 3 of the 4 subsequent discrimination tasks. Further, the results showed that discrimination learning performance of both mouse strains was largely unaffected by the odor stimuli used. The results of the present study demonstrate differences between an outbred and an inbred strain of mice with regard to odor discrimination learning, a classical measure of cognitive performance in comparative psychology. Thus, they emphasize the need to be careful with generalizing statements as to cognitive or sensory abilities of Mus musculus when inbred strains of mice are used.

PMID: 26123553 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhWl6

Global Survey of Variation in a Human Olfactory Receptor Gene Reveals Signatures of Non-Neutral Evolution.

Related Articles

Global Survey of Variation in a Human Olfactory Receptor Gene Reveals Signatures of Non-Neutral Evolution.

Chem Senses. 2015 Sep;40(7):481-8

Authors: Hoover KC, Gokcumen O, Qureshy Z, Bruguera E, Savangsuksa A, Cobb M, Matsunami H

Abstract
Allelic variation at 4 loci in the human olfactory receptor gene OR7D4 is associated with perceptual variation in the sex steroid-derived odorants, androstenone, and androstadienone. Androstadienone has been linked with chemosensory identification whereas androstenone makes pork from uncastrated pigs distasteful ("boar taint"). In a sample of 2224 individuals from 43 populations, we identified 45 OR7D4 single nucleotide polymorphisms. Coalescent modeling of frequency-site-spectrum-based statistics identified significant deviation from neutrality in human OR7D4; individual populations with statistically significant deviations from neutrality include Gujarati, Beijing Han, Great Britain, Iberia, and Puerto Rico. Analysis of molecular variation values indicated statistically significant population differentiation driven mainly by the 4 alleles associated with androstenone perception variation; however, fixation values were low suggesting that genetic structure may not have played a strong role in creating these group divisions. We also studied OR7D4 in the genomes of extinct members of the human lineage: Altai Neandertal and Denisovan. No variants were identified in Altai but 2 were in Denisova, one of which is shared by modern humans and one of which is novel. A functional test of modern human and a synthesized mutant Denisova OR7D4 indicated no statistically significant difference in responses to androstenone between the 2 species. Our results suggest non-neutral evolution for an olfactory receptor gene.

PMID: 26072518 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1GnCcLt

Endocrine Modulation of Olfactory Responsiveness: Effects of the Orexigenic Hormone Ghrelin.

Related Articles

Endocrine Modulation of Olfactory Responsiveness: Effects of the Orexigenic Hormone Ghrelin.

Chem Senses. 2015 Sep;40(7):469-79

Authors: Loch D, Breer H, Strotmann J

Abstract
Finding food sources is a prerequisite for an acute food intake. This process is initiated by ghrelin released from X/A-like cells of the gastrointestinal tract. Because food finding often depends on olfaction, the question arises whether ghrelin may affect the responsiveness of the olfactory system. Monitoring odor-induced activation of the mouse olfactory epithelium via Egr1 expression revealed that after a nasal application of ghrelin, more sensory neurons responded upon odor exposure indicating an increased responsiveness. The higher reactivity of olfactory neurons was accompanied with an increased activity of receptor-specific glomeruli. In search for mechanisms underlying the ghrelin-mediated sensitization of olfactory neurons, it was shown that Ghsr1a, the ghrelin receptor gene, but not the hormone itself was expressed in the olfactory epithelium. Further analysis of isolated cells revealed that the receptor was in fact expressed in mature olfactory sensory neurons. Treatment with a ghrelin receptor antagonist abolished the ghrelin effect, strengthening the notion that ghrelin and its receptor are responsible for the enhanced neuronal responsiveness. In contrast to the effects of the "hunger" hormone ghrelin, the short-term "satiety" hormone PYY3-36 did not affect olfactory responsiveness. The results demonstrate that ghrelin, which signals acute hunger, renders the olfactory system more responsive to odors.

PMID: 26071307 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1L8cbE1

Normal Taste Acceptance and Preference of PANX1 Knockout Mice.

Related Articles

Normal Taste Acceptance and Preference of PANX1 Knockout Mice.

Chem Senses. 2015 Sep;40(7):453-9

Authors: Tordoff MG, Aleman TR, Ellis HT, Ohmoto M, Matsumoto I, Shestopalov VI, Mitchell CH, Foskett JK, Poole RL

Abstract
Taste compounds detected by G protein-coupled receptors on the apical surface of Type 2 taste cells initiate an intracellular molecular cascade culminating in the release of ATP. It has been suggested that this ATP release is accomplished by pannexin 1 (PANX1). However, we report here that PANX1 knockout mice do not differ from wild-type controls in response to representative taste solutions, measured using 5-s brief-access tests or 48-h two-bottle choice tests. This implies that PANX1 is unnecessary for taste detection and consequently that ATP release from Type 2 taste cells does not require PANX1.

PMID: 25987548 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3X3k

Why do we like sweet taste: A bitter tale?

Why do we like sweet taste: A bitter tale?

Physiol Behav. 2016 May 9;

Authors: Beauchamp GK

Abstract
Sweet is widely considered to be one of a small number of basic or primary taste qualities. Liking for sweet tasting substances is innate, although postnatal experiences can shape responses. The power of sweet taste to induce consumption and to motivate behavior is profound, suggesting the importance of this sense for many species. Most investigators presume that the ability to identify sweet molecules through the sense of taste evolved to allow organisms to detect sources of readily available glucose from plants. Perhaps the best evidence supporting this presumption are recent discoveries in comparative biology demonstrating that species in the order Carnivora that do not consume plants also do not perceive sweet taste due to the pseudogenization of a component of the primary sweet taste receptor. However, arguing against this idea is the observation that the sweetness of a plant, or the amount of easily metabolizable sugars contained in the plant, provides little quantitative indication of the plant's energy or broadly conceived food value. Here it is suggested that the perceptual ratio of sweet taste to bitter taste (a signal for toxicity) may be a better gauge of a plant's broadly conceived food value than sweetness alone and that it is this ratio that helps guide selection or rejection of a potential plant food.

PMID: 27174610 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhPpS

The Association Between Olfaction and Depression: A Systematic Review.

The Association Between Olfaction and Depression: A Systematic Review.

Chem Senses. 2016 May 11;

Authors: Kohli P, Soler ZM, Nguyen SA, Muus JS, Schlosser RJ

Abstract
Previous studies on the relationship between olfaction and depression have revealed mixed results. In addition, few have focused on the reciprocity of this association. The aim of this study is to combine depression and olfactory data in two separate patient populations to further understand their association. A systematic literature review was conducted using 3 online databases to identify studies correlating olfaction and depression in patients presenting with either primary depression or primary olfactory dysfunction. For the depressed population, weighted means and standard deviations for the Sniffin' Sticks Test and the 40-item Smell Identification Test were combined using 10 studies. For the olfactory dysfunction population, weighted means of Beck's Depression Inventory were combined using 3 studies. Independent t-tests were used to compare differences between groups. Comparing primary depressed patients with controls, depressed patients showed decreased scores in olfactory threshold (6.31±1.38 vs. 6.78±0.88, P = 0.0005), discrimination (12.05±1.44 vs. 12.66±1.36, P = 0.0073), identification (12.57±0.74 vs. 12.98±0.90, P < 0.0001), and 40-Item Smell Identification Test (35.31±1.91 vs. 37.41±1.45, P < 0.0001). In patients with primary olfactory dysfunction, Beck's Depression Inventory scores were significantly different between patients classified as normosmics, hyposmics and anosmics (5.21±4.73 vs. 10.93±9.25 vs. 14.15±5.39, P ≤ 0.0274 for all 3 comparisons). In conclusion, patients with depression have reduced olfactory performance when compared with the healthy controls and conversely, patients with olfactory dysfunction, have symptoms of depression that worsen with severity of smell loss.

PMID: 27170667 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3VbW

Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS).

Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS).

Chem Senses. 2016 May 11;

Authors: Hoffmann-Hensel SM, Freiherr J

Abstract
Priming describes the principle of modified stimulus perception that occurs due to a previously presented stimulus. Although we have begun to understand the mechanisms of crossmodal priming, the concept of intramodal olfactory priming remains relatively unexplored. Therefore, we applied positive and negative odors using respiration-triggered olfactory stimulation (RETROS), enabling us to record the skin conductance response (SCR) and breathing data without a crossmodal cueing error and measure reaction times (RTs) for olfactory tasks. RT, SCR, and breathing data revealed that negative odors were perceived significantly more arousing than positive ones. In a second experiment, 2 odors were applied during consecutive respirations. Here, we observed intramodal olfactory priming effects: A negative odor preceded by a positive odor was rated as more pleasant than when the same odor was preceded by a negative odor. Additionally, a longer identification RT was found for the second compared with the first odor. We interpret this as increased "perceptual load" due to incomplete first odor processing while the second odor was presented. Furthermore, intramodal priming can be considered a possible reason for the increase of identification RT. The use of RETROS led to these novel insights into olfactory processing beyond crossmodal interaction by providing a noncued unimodal olfactory test, and therefore, RETROS can be used in the experimental design of future olfactory studies.

PMID: 27170666 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhTWs

Why do we like sweet taste: A bitter tale?

Why do we like sweet taste: A bitter tale?

Physiol Behav. 2016 May 9;

Authors: Beauchamp GK

Abstract
Sweet is widely considered to be one of a small number of basic or primary taste qualities. Liking for sweet tasting substances is innate, although postnatal experiences can shape responses. The power of sweet taste to induce consumption and to motivate behavior is profound, suggesting the importance of this sense for many species. Most investigators presume that the ability to identify sweet molecules through the sense of taste evolved to allow organisms to detect sources of readily available glucose from plants. Perhaps the best evidence supporting this presumption are recent discoveries in comparative biology demonstrating that species in the order Carnivora that do not consume plants also do not perceive sweet taste due to the pseudogenization of a component of the primary sweet taste receptor. However, arguing against this idea is the observation that the sweetness of a plant, or the amount of easily metabolizable sugars contained in the plant, provides little quantitative indication of the plant's energy or broadly conceived food value. Here it is suggested that the perceptual ratio of sweet taste to bitter taste (a signal for toxicity) may be a better gauge of a plant's broadly conceived food value than sweetness alone and that it is this ratio that helps guide selection or rejection of a potential plant food.

PMID: 27174610 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhPpS

The Association Between Olfaction and Depression: A Systematic Review.

The Association Between Olfaction and Depression: A Systematic Review.

Chem Senses. 2016 May 11;

Authors: Kohli P, Soler ZM, Nguyen SA, Muus JS, Schlosser RJ

Abstract
Previous studies on the relationship between olfaction and depression have revealed mixed results. In addition, few have focused on the reciprocity of this association. The aim of this study is to combine depression and olfactory data in two separate patient populations to further understand their association. A systematic literature review was conducted using 3 online databases to identify studies correlating olfaction and depression in patients presenting with either primary depression or primary olfactory dysfunction. For the depressed population, weighted means and standard deviations for the Sniffin' Sticks Test and the 40-item Smell Identification Test were combined using 10 studies. For the olfactory dysfunction population, weighted means of Beck's Depression Inventory were combined using 3 studies. Independent t-tests were used to compare differences between groups. Comparing primary depressed patients with controls, depressed patients showed decreased scores in olfactory threshold (6.31±1.38 vs. 6.78±0.88, P = 0.0005), discrimination (12.05±1.44 vs. 12.66±1.36, P = 0.0073), identification (12.57±0.74 vs. 12.98±0.90, P < 0.0001), and 40-Item Smell Identification Test (35.31±1.91 vs. 37.41±1.45, P < 0.0001). In patients with primary olfactory dysfunction, Beck's Depression Inventory scores were significantly different between patients classified as normosmics, hyposmics and anosmics (5.21±4.73 vs. 10.93±9.25 vs. 14.15±5.39, P ≤ 0.0274 for all 3 comparisons). In conclusion, patients with depression have reduced olfactory performance when compared with the healthy controls and conversely, patients with olfactory dysfunction, have symptoms of depression that worsen with severity of smell loss.

PMID: 27170667 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3VbW

Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS).

Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS).

Chem Senses. 2016 May 11;

Authors: Hoffmann-Hensel SM, Freiherr J

Abstract
Priming describes the principle of modified stimulus perception that occurs due to a previously presented stimulus. Although we have begun to understand the mechanisms of crossmodal priming, the concept of intramodal olfactory priming remains relatively unexplored. Therefore, we applied positive and negative odors using respiration-triggered olfactory stimulation (RETROS), enabling us to record the skin conductance response (SCR) and breathing data without a crossmodal cueing error and measure reaction times (RTs) for olfactory tasks. RT, SCR, and breathing data revealed that negative odors were perceived significantly more arousing than positive ones. In a second experiment, 2 odors were applied during consecutive respirations. Here, we observed intramodal olfactory priming effects: A negative odor preceded by a positive odor was rated as more pleasant than when the same odor was preceded by a negative odor. Additionally, a longer identification RT was found for the second compared with the first odor. We interpret this as increased "perceptual load" due to incomplete first odor processing while the second odor was presented. Furthermore, intramodal priming can be considered a possible reason for the increase of identification RT. The use of RETROS led to these novel insights into olfactory processing beyond crossmodal interaction by providing a noncued unimodal olfactory test, and therefore, RETROS can be used in the experimental design of future olfactory studies.

PMID: 27170666 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhTWs

A Drosophila Gustatory Receptor Required for Strychnine Sensation.

Related Articles

A Drosophila Gustatory Receptor Required for Strychnine Sensation.

Chem Senses. 2015 Sep;40(7):525-33

Authors: Lee Y, Moon SJ, Wang Y, Montell C

Abstract
Strychnine is a potent, naturally occurring neurotoxin that effectively protects plants from animal pests by deterring feeding behavior. In insects, such as the fruit fly, Drosophila melanogaster, bitter-tasting aversive compounds are detected primarily through a family of gustatory receptors (GRs), which are expressed in gustatory receptor neurons. We previously described multiple GRs that eliminate the behavioral avoidance to all bitter compounds tested, with the exception of strychnine. Here, we report the identity of a strychnine receptor, referred to as GR47a. We generated a mutation in Gr47a and found that it eliminated strychnine repulsion and strychnine-induced action potentials. GR47a was narrowly tuned, as the responses to other avoidance compounds were unaffected in the mutant animals. This analysis supports an emerging model that Drosophila GRs fall broadly into two specificity classes-one class is comprised of core receptors that are broadly required, whereas the other class, which includes GR47a, consists of narrowly tuned receptors that define chemical specificity.

PMID: 26187906 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3QEX

Oleogustus: The Unique Taste of Fat.

Related Articles

Oleogustus: The Unique Taste of Fat.

Chem Senses. 2015 Sep;40(7):507-16

Authors: Running CA, Craig BA, Mattes RD

Abstract
Considerable mechanistic data indicate there may be a sixth basic taste: fat. However, evidence demonstrating that the sensation of nonesterified fatty acids (NEFA, the proposed stimuli for "fat taste") differs qualitatively from other tastes is lacking. Using perceptual mapping, we demonstrate that medium and long-chain NEFA have a taste sensation that is distinct from other basic tastes (sweet, sour, salty, and bitter). Although some overlap was observed between these NEFA and umami taste, this overlap is likely due to unfamiliarity with umami sensations rather than true similarity. Shorter chain fatty acids stimulate a sensation similar to sour, but as chain length increases this sensation changes. Fat taste oral signaling, and the different signals caused by different alkyl chain lengths, may hold implications for food product development, clinical practice, and public health policy.

PMID: 26142421 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhLGE

Odor Emotional Quality Predicts Odor Identification.

Related Articles

Odor Emotional Quality Predicts Odor Identification.

Chem Senses. 2015 Sep;40(7):517-23

Authors: Bestgen AK, Schulze P, Kuchinke L

Abstract
It is commonly agreed upon a strong link between emotion and olfaction. Odor-evoked memories are experienced as more emotional compared with verbal, visual, and tactile stimuli. Moreover, the emotional quality of odor cues increases memory performance, but contrary to this, odors are poor retrieval cues for verbal labels. To examine the relation between the emotional quality of an odor and its likelihood of identification, this study evaluates how normative emotion ratings based on the 3-dimensional affective space model (that includes valence, arousal, and dominance), using the Self-Assessment Manikin by Bradley and Lang (Bradley MM, Lang PJ. 1994. Measuring emotion: the Self-Assessment Manikin and the Semantic Differential. J Behav Ther Exp Psychiatry. 25(1):49-59.) and the Positive and Negative Affect Schedule (Watson D, Clark LA, Tellegen A. 1988. Development and validation of brief measures of positive and negative affect: the PANAS scales. J Pers Soc Psychol. 54(6):1063-1070.) predict the identification of odors in a multiple choice condition. The best fitting logistic regression model includes squared valence and dominance and thus, points to a significant role of specific emotional features of odors as a main clue for odor identification.

PMID: 26142420 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3QFc

Mice Lacking Pannexin 1 Release ATP and Respond Normally to All Taste Qualities.

Related Articles

Mice Lacking Pannexin 1 Release ATP and Respond Normally to All Taste Qualities.

Chem Senses. 2015 Sep;40(7):461-7

Authors: Vandenbeuch A, Anderson CB, Kinnamon SC

Abstract
Adenosine triphosphate (ATP) is required for the transmission of all taste qualities from taste cells to afferent nerve fibers. ATP is released from Type II taste cells by a nonvesicular mechanism and activates purinergic receptors containing P2X2 and P2X3 on nerve fibers. Several ATP release channels are expressed in taste cells including CALHM1, Pannexin 1, Connexin 30, and Connexin 43, but whether all are involved in ATP release is not clear. We have used a global Pannexin 1 knock out (Panx1 KO) mouse in a series of in vitro and in vivo experiments. Our results confirm that Panx1 channels are absent in taste buds of the knockout mice and that other known ATP release channels are not upregulated. Using a luciferin/luciferase assay, we show that circumvallate taste buds from Panx1 KO mice normally release ATP upon taste stimulation compared with wild type (WT) mice. Gustatory nerve recordings in response to various tastants applied to the tongue and brief-access behavioral testing with SC45647 also show no difference between Panx1 KO and WT. These results confirm that Panx1 is not required for the taste evoked release of ATP or for neural and behavioral responses to taste stimuli.

PMID: 26136251 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhWS8

Enhancement of Odor Sensitivity Following Repeated Odor and Visual Fear Conditioning.

Related Articles

Enhancement of Odor Sensitivity Following Repeated Odor and Visual Fear Conditioning.

Chem Senses. 2015 Sep;40(7):497-506

Authors: Parma V, Ferraro S, Miller SS, Åhs F, Lundström JN

Abstract
Odor detection sensitivity can be rapidly altered by fear conditioning; whether this effect is augmented over time is not known. The present study aimed to test whether repeated conditioning sessions induce changes in odor detection threshold as well as in conditioned responses and whether olfactory stimuli evoke stronger conditioned responses than visual stimuli. The repeated conditioning group participated in repeated sessions over 2 weeks whereas the single conditioning group participated in 1 conditioning session; both groups were presented with visual and olfactory stimuli, were paired with an electric shock (CS+) and 2 matched control stimuli not paired with shock (CS-) while olfactory detection threshold and skin conductance responses (SCRs) were measured before and after the last session. We found increased sensitivity for the CS+ odor in the repeated but not in the single conditioning group, consistent with changes in olfactory sensitivity following repeated aversive learning and of a similar magnitude to what has previously been demonstrated in the periphery. SCR to the visual and olfactory CS+ were similar between groups, indicating that sensory thresholds can change without corresponding change in conditioned responses. In conclusion, repeated conditioning increases detection sensitivity and reduces conditioned responses, suggesting that segregated processes influence perception and conditioned responses.

PMID: 26126729 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3VIS

Olfactory Discrimination Learning in an Outbred and an Inbred Strain of Mice.

Related Articles

Olfactory Discrimination Learning in an Outbred and an Inbred Strain of Mice.

Chem Senses. 2015 Sep;40(7):489-96

Authors: Laska M

Abstract
The present study compared olfactory discrimination learning in CD-1 mice, a widely used outbred strain of mice with that of C57BL/6J mice, one of the most widely used inbred mouse strains. Using an automated olfactometer and a standard operant conditioning procedure, I found that CD-1 mice needed 60 trials to reach learning criterion in an initial 2-odor discrimination task. They improved in learning speed in subsequent discrimination tasks in which either the rewarded or the unrewarded stimulus was replaced for a new stimulus. C57BL/6J mice, in contrast, needed 120 trials to reach learning criterion in an initial 2-odor discrimination task and also needed significantly more trials than the CD-1 mice in 3 of the 4 subsequent discrimination tasks. Further, the results showed that discrimination learning performance of both mouse strains was largely unaffected by the odor stimuli used. The results of the present study demonstrate differences between an outbred and an inbred strain of mice with regard to odor discrimination learning, a classical measure of cognitive performance in comparative psychology. Thus, they emphasize the need to be careful with generalizing statements as to cognitive or sensory abilities of Mus musculus when inbred strains of mice are used.

PMID: 26123553 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1WwhWl6

Global Survey of Variation in a Human Olfactory Receptor Gene Reveals Signatures of Non-Neutral Evolution.

Related Articles

Global Survey of Variation in a Human Olfactory Receptor Gene Reveals Signatures of Non-Neutral Evolution.

Chem Senses. 2015 Sep;40(7):481-8

Authors: Hoover KC, Gokcumen O, Qureshy Z, Bruguera E, Savangsuksa A, Cobb M, Matsunami H

Abstract
Allelic variation at 4 loci in the human olfactory receptor gene OR7D4 is associated with perceptual variation in the sex steroid-derived odorants, androstenone, and androstadienone. Androstadienone has been linked with chemosensory identification whereas androstenone makes pork from uncastrated pigs distasteful ("boar taint"). In a sample of 2224 individuals from 43 populations, we identified 45 OR7D4 single nucleotide polymorphisms. Coalescent modeling of frequency-site-spectrum-based statistics identified significant deviation from neutrality in human OR7D4; individual populations with statistically significant deviations from neutrality include Gujarati, Beijing Han, Great Britain, Iberia, and Puerto Rico. Analysis of molecular variation values indicated statistically significant population differentiation driven mainly by the 4 alleles associated with androstenone perception variation; however, fixation values were low suggesting that genetic structure may not have played a strong role in creating these group divisions. We also studied OR7D4 in the genomes of extinct members of the human lineage: Altai Neandertal and Denisovan. No variants were identified in Altai but 2 were in Denisova, one of which is shared by modern humans and one of which is novel. A functional test of modern human and a synthesized mutant Denisova OR7D4 indicated no statistically significant difference in responses to androstenone between the 2 species. Our results suggest non-neutral evolution for an olfactory receptor gene.

PMID: 26072518 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1GnCcLt

Endocrine Modulation of Olfactory Responsiveness: Effects of the Orexigenic Hormone Ghrelin.

Related Articles

Endocrine Modulation of Olfactory Responsiveness: Effects of the Orexigenic Hormone Ghrelin.

Chem Senses. 2015 Sep;40(7):469-79

Authors: Loch D, Breer H, Strotmann J

Abstract
Finding food sources is a prerequisite for an acute food intake. This process is initiated by ghrelin released from X/A-like cells of the gastrointestinal tract. Because food finding often depends on olfaction, the question arises whether ghrelin may affect the responsiveness of the olfactory system. Monitoring odor-induced activation of the mouse olfactory epithelium via Egr1 expression revealed that after a nasal application of ghrelin, more sensory neurons responded upon odor exposure indicating an increased responsiveness. The higher reactivity of olfactory neurons was accompanied with an increased activity of receptor-specific glomeruli. In search for mechanisms underlying the ghrelin-mediated sensitization of olfactory neurons, it was shown that Ghsr1a, the ghrelin receptor gene, but not the hormone itself was expressed in the olfactory epithelium. Further analysis of isolated cells revealed that the receptor was in fact expressed in mature olfactory sensory neurons. Treatment with a ghrelin receptor antagonist abolished the ghrelin effect, strengthening the notion that ghrelin and its receptor are responsible for the enhanced neuronal responsiveness. In contrast to the effects of the "hunger" hormone ghrelin, the short-term "satiety" hormone PYY3-36 did not affect olfactory responsiveness. The results demonstrate that ghrelin, which signals acute hunger, renders the olfactory system more responsive to odors.

PMID: 26071307 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1L8cbE1

Normal Taste Acceptance and Preference of PANX1 Knockout Mice.

Related Articles

Normal Taste Acceptance and Preference of PANX1 Knockout Mice.

Chem Senses. 2015 Sep;40(7):453-9

Authors: Tordoff MG, Aleman TR, Ellis HT, Ohmoto M, Matsumoto I, Shestopalov VI, Mitchell CH, Foskett JK, Poole RL

Abstract
Taste compounds detected by G protein-coupled receptors on the apical surface of Type 2 taste cells initiate an intracellular molecular cascade culminating in the release of ATP. It has been suggested that this ATP release is accomplished by pannexin 1 (PANX1). However, we report here that PANX1 knockout mice do not differ from wild-type controls in response to representative taste solutions, measured using 5-s brief-access tests or 48-h two-bottle choice tests. This implies that PANX1 is unnecessary for taste detection and consequently that ATP release from Type 2 taste cells does not require PANX1.

PMID: 25987548 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qk3X3k

A Neural Mechanism of Taste Perception Modulated by Odor Information

Taste perception is significantly affected by other sensory modalities such as vision, smell, and somatosensation. Such taste sensation elicited by integrating gustatory and other sensory information is referred to as flavor. Although experimental studies have demonstrated the characteristics of flavor perception influenced by other sensory modalities and the involved brain areas, it remains unknown how flavor emerges from the brain circuits. Of the involved brain areas, orbitofrontal cortex (OFC), as well as gustatory cortex (GC), plays a dominant role in flavor perception. We develop here a neural model of gustatory system which consists of GC and OFC networks and examine the neural mechanism of odor-induced taste perception. Using the model, we show that flavor perception is shaped by experience-dependent learning of foods with congruent taste–odor pairs, providing a unique representation of flavor through the interaction between OFC and GC neurons. Our model also shows that feedback signals from OFC to GC modulate the dynamic stability of taste attractors in GC, leading to the enhancement or suppression of taste responses by smells. Furthermore, modeling shows that spatial variability in GC activity evoked by tastants determines to what extent odor enhances congruent taste responses. The results suggest that flavor perception is deeply associated with dynamic stability of GC attractors through the interaction between GC and OFC.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1R1BhlJ

The Association Between Olfaction and Depression: A Systematic Review

Previous studies on the relationship between olfaction and depression have revealed mixed results. In addition, few have focused on the reciprocity of this association. The aim of this study is to combine depression and olfactory data in two separate patient populations to further understand their association. A systematic literature review was conducted using 3 online databases to identify studies correlating olfaction and depression in patients presenting with either primary depression or primary olfactory dysfunction. For the depressed population, weighted means and standard deviations for the Sniffin’ Sticks Test and the 40-item Smell Identification Test were combined using 10 studies. For the olfactory dysfunction population, weighted means of Beck’s Depression Inventory were combined using 3 studies. Independent t-tests were used to compare differences between groups. Comparing primary depressed patients with controls, depressed patients showed decreased scores in olfactory threshold (6.31±1.38 vs. 6.78±0.88, P = 0.0005), discrimination (12.05±1.44 vs. 12.66±1.36, P = 0.0073), identification (12.57±0.74 vs. 12.98±0.90, P < 0.0001), and 40-Item Smell Identification Test (35.31±1.91 vs. 37.41±1.45, P < 0.0001). In patients with primary olfactory dysfunction, Beck’s Depression Inventory scores were significantly different between patients classified as normosmics, hyposmics and anosmics (5.21±4.73 vs. 10.93±9.25 vs. 14.15±5.39, P ≤ 0.0274 for all 3 comparisons). In conclusion, patients with depression have reduced olfactory performance when compared with the healthy controls and conversely, patients with olfactory dysfunction, have symptoms of depression that worsen with severity of smell loss.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/27ftLzp

Intramodal Olfactory Priming of Positive and Negative Odors in Humans Using Respiration-Triggered Olfactory Stimulation (RETROS)

Priming describes the principle of modified stimulus perception that occurs due to a previously presented stimulus. Although we have begun to understand the mechanisms of crossmodal priming, the concept of intramodal olfactory priming remains relatively unexplored. Therefore, we applied positive and negative odors using respiration-triggered olfactory stimulation (RETROS), enabling us to record the skin conductance response (SCR) and breathing data without a crossmodal cueing error and measure reaction times (RTs) for olfactory tasks. RT, SCR, and breathing data revealed that negative odors were perceived significantly more arousing than positive ones. In a second experiment, 2 odors were applied during consecutive respirations. Here, we observed intramodal olfactory priming effects: A negative odor preceded by a positive odor was rated as more pleasant than when the same odor was preceded by a negative odor. Additionally, a longer identification RT was found for the second compared with the first odor. We interpret this as increased "perceptual load" due to incomplete first odor processing while the second odor was presented. Furthermore, intramodal priming can be considered a possible reason for the increase of identification RT. The use of RETROS led to these novel insights into olfactory processing beyond crossmodal interaction by providing a noncued unimodal olfactory test, and therefore, RETROS can be used in the experimental design of future olfactory studies.

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1T7oJLM

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides.

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides.

Proc Natl Acad Sci U S A. 2016 May 9;

Authors: Sukumaran SK, Yee KK, Iwata S, Kotha R, Quezada-Calvillo R, Nichols BL, Mohan S, Pinto BM, Shigemura N, Ninomiya Y, Margolskee RF

Abstract
The primary sweet sensor in mammalian taste cells for sugars and noncaloric sweeteners is the heteromeric combination of type 1 taste receptors 2 and 3 (T1R2+T1R3, encoded by Tas1r2 and Tas1r3 genes). However, in the absence of T1R2+T1R3 (e.g., in Tas1r3 KO mice), animals still respond to sugars, arguing for the presence of T1R-independent detection mechanism(s). Our previous findings that several glucose transporters (GLUTs), sodium glucose cotransporter 1 (SGLT1), and the ATP-gated K(+) (KATP) metabolic sensor are preferentially expressed in the same taste cells with T1R3 provides a potential explanation for the T1R-independent detection of sugars: sweet-responsive taste cells that respond to sugars and sweeteners may contain a T1R-dependent (T1R2+T1R3) sweet-sensing pathway for detecting sugars and noncaloric sweeteners, as well as a T1R-independent (GLUTs, SGLT1, KATP) pathway for detecting monosaccharides. However, the T1R-independent pathway would not explain responses to disaccharide and oligomeric sugars, such as sucrose, maltose, and maltotriose, which are not substrates for GLUTs or SGLT1. Using RT-PCR, quantitative PCR, in situ hybridization, and immunohistochemistry, we found that taste cells express multiple α-glycosidases (e.g., amylase and neutral α glucosidase C) and so-called intestinal "brush border" disaccharide-hydrolyzing enzymes (e.g., maltase-glucoamylase and sucrase-isomaltase). Treating the tongue with inhibitors of disaccharidases specifically decreased gustatory nerve responses to disaccharides, but not to monosaccharides or noncaloric sweeteners, indicating that lingual disaccharidases are functional. These taste cell-expressed enzymes may locally break down dietary disaccharides and starch hydrolysis products into monosaccharides that could serve as substrates for the T1R-independent sugar sensing pathways.

PMID: 27162343 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qdiPk6

Chemosensory Dysfunction in Alcohol-Related Disorders: A Joint Exploration of Olfaction and Taste.

Related Articles

Chemosensory Dysfunction in Alcohol-Related Disorders: A Joint Exploration of Olfaction and Taste.

Chem Senses. 2015 Nov;40(9):605-8

Authors: Brion M, de Timary P, Vander Stappen C, Guettat L, Lecomte B, Rombaux P, Maurage P

Abstract
Chemosensory (olfaction-taste) dysfunctions are considered as reliable biomarkers in many neurological and psychiatric states. However, experimental measures of chemosensory abilities are lacking in alcohol-dependence (AD) and Korsakoff Syndrome (KS, a neurological complication of AD), despite the role played by alcohol-related odors and taste in the emergence and maintenance of AD. This study thus investigated chemosensory impairments in AD and KS. Olfactory-gustatory measures were taken among 20 KS, 20 AD, and 20 control participants. Olfaction (odor detection-discrimination-identification) was assessed using the "Sniffin Sticks" battery and taste was measured using the "Taste Strips" task. Impairments were found for high-level olfaction in AD (odor discrimination) and KS (odor discrimination-identification), even after controlling for psychopathological comorbidities. Gustatory deficits were also observed in both groups, indexing a global deficit for chemosensory perception. Finally, the gradient of impairment between the successive disease stages for odor identification suggests that the hypothesis of a continuum between AD and KS regarding cognitive deficits can be generalized to chemosensory perception. AD and KS are thus characterized by deficits in chemosensory abilities, which could constitute a marker of the AD-KS transition. In view of its deleterious influence on everyday life, chemosensory dysfunction should also be taken into account in clinical settings.

PMID: 26354933 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1X0uK1C

The Insect Chemoreceptor Superfamily Is Ancient in Animals.

Related Articles

The Insect Chemoreceptor Superfamily Is Ancient in Animals.

Chem Senses. 2015 Nov;40(9):609-14

Authors: Robertson HM

Abstract
The insect chemoreceptor superfamily consists of 2 gene families, the highly diverse gustatory receptors (GRs) found in all arthropods with sequenced genomes and the odorant receptors that evolved from a GR lineage and have been found only in insects to date. Here, I describe relatives of the insect chemoreceptor superfamily, specifically the basal GR family, in diverse other animals, showing that the superfamily dates back at least to early animal evolution. GR-Like (GRL) genes are present in the genomes of the placozoan Trichoplax adhaerens, an anemone Nematostella vectensis, a coral Acropora digitifera, a polychaete Capitella teleta, a leech Helobdella robusta, the nematode Caenorhabditis elegans (and many other nematodes), 3 molluscs (a limpet Lottia gigantea, an oyster Crassostrea gigas, and the sea hare Aplysia californica), the sea urchin Strongylocentrotus purpuratus, and the sea acorn Saccoglossus kowalevskii. While some of these animals contain multiple divergent GRL lineages, GRLs have been lost entirely from other animal lineages such as vertebrates. GRLs are absent from the ctenophore Mnemiopsis leidyi, the demosponge Amphimedon queenslandica, and 2 available chaonoflagellate genomes, so it remains unclear whether this superfamily originated before or during animal evolution.

PMID: 26354932 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1OJph9u

Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

Related Articles

Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

Elife. 2015;4

Authors: Clare EL, Holderied MW

Abstract
Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an 'acoustic shadow' cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for 'acoustic camouflage' as an anti-predator defence mechanism.

PMID: 26327624 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/24KDT0N

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides.

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides.

Proc Natl Acad Sci U S A. 2016 May 9;

Authors: Sukumaran SK, Yee KK, Iwata S, Kotha R, Quezada-Calvillo R, Nichols BL, Mohan S, Pinto BM, Shigemura N, Ninomiya Y, Margolskee RF

Abstract
The primary sweet sensor in mammalian taste cells for sugars and noncaloric sweeteners is the heteromeric combination of type 1 taste receptors 2 and 3 (T1R2+T1R3, encoded by Tas1r2 and Tas1r3 genes). However, in the absence of T1R2+T1R3 (e.g., in Tas1r3 KO mice), animals still respond to sugars, arguing for the presence of T1R-independent detection mechanism(s). Our previous findings that several glucose transporters (GLUTs), sodium glucose cotransporter 1 (SGLT1), and the ATP-gated K(+) (KATP) metabolic sensor are preferentially expressed in the same taste cells with T1R3 provides a potential explanation for the T1R-independent detection of sugars: sweet-responsive taste cells that respond to sugars and sweeteners may contain a T1R-dependent (T1R2+T1R3) sweet-sensing pathway for detecting sugars and noncaloric sweeteners, as well as a T1R-independent (GLUTs, SGLT1, KATP) pathway for detecting monosaccharides. However, the T1R-independent pathway would not explain responses to disaccharide and oligomeric sugars, such as sucrose, maltose, and maltotriose, which are not substrates for GLUTs or SGLT1. Using RT-PCR, quantitative PCR, in situ hybridization, and immunohistochemistry, we found that taste cells express multiple α-glycosidases (e.g., amylase and neutral α glucosidase C) and so-called intestinal "brush border" disaccharide-hydrolyzing enzymes (e.g., maltase-glucoamylase and sucrase-isomaltase). Treating the tongue with inhibitors of disaccharidases specifically decreased gustatory nerve responses to disaccharides, but not to monosaccharides or noncaloric sweeteners, indicating that lingual disaccharidases are functional. These taste cell-expressed enzymes may locally break down dietary disaccharides and starch hydrolysis products into monosaccharides that could serve as substrates for the T1R-independent sugar sensing pathways.

PMID: 27162343 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qdiPk6

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides.

Taste cell-expressed α-glucosidase enzymes contribute to gustatory responses to disaccharides.

Proc Natl Acad Sci U S A. 2016 May 9;

Authors: Sukumaran SK, Yee KK, Iwata S, Kotha R, Quezada-Calvillo R, Nichols BL, Mohan S, Pinto BM, Shigemura N, Ninomiya Y, Margolskee RF

Abstract
The primary sweet sensor in mammalian taste cells for sugars and noncaloric sweeteners is the heteromeric combination of type 1 taste receptors 2 and 3 (T1R2+T1R3, encoded by Tas1r2 and Tas1r3 genes). However, in the absence of T1R2+T1R3 (e.g., in Tas1r3 KO mice), animals still respond to sugars, arguing for the presence of T1R-independent detection mechanism(s). Our previous findings that several glucose transporters (GLUTs), sodium glucose cotransporter 1 (SGLT1), and the ATP-gated K(+) (KATP) metabolic sensor are preferentially expressed in the same taste cells with T1R3 provides a potential explanation for the T1R-independent detection of sugars: sweet-responsive taste cells that respond to sugars and sweeteners may contain a T1R-dependent (T1R2+T1R3) sweet-sensing pathway for detecting sugars and noncaloric sweeteners, as well as a T1R-independent (GLUTs, SGLT1, KATP) pathway for detecting monosaccharides. However, the T1R-independent pathway would not explain responses to disaccharide and oligomeric sugars, such as sucrose, maltose, and maltotriose, which are not substrates for GLUTs or SGLT1. Using RT-PCR, quantitative PCR, in situ hybridization, and immunohistochemistry, we found that taste cells express multiple α-glycosidases (e.g., amylase and neutral α glucosidase C) and so-called intestinal "brush border" disaccharide-hydrolyzing enzymes (e.g., maltase-glucoamylase and sucrase-isomaltase). Treating the tongue with inhibitors of disaccharidases specifically decreased gustatory nerve responses to disaccharides, but not to monosaccharides or noncaloric sweeteners, indicating that lingual disaccharidases are functional. These taste cell-expressed enzymes may locally break down dietary disaccharides and starch hydrolysis products into monosaccharides that could serve as substrates for the T1R-independent sugar sensing pathways.

PMID: 27162343 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1qdiPk6

Chemosensory Dysfunction in Alcohol-Related Disorders: A Joint Exploration of Olfaction and Taste.

Related Articles

Chemosensory Dysfunction in Alcohol-Related Disorders: A Joint Exploration of Olfaction and Taste.

Chem Senses. 2015 Nov;40(9):605-8

Authors: Brion M, de Timary P, Vander Stappen C, Guettat L, Lecomte B, Rombaux P, Maurage P

Abstract
Chemosensory (olfaction-taste) dysfunctions are considered as reliable biomarkers in many neurological and psychiatric states. However, experimental measures of chemosensory abilities are lacking in alcohol-dependence (AD) and Korsakoff Syndrome (KS, a neurological complication of AD), despite the role played by alcohol-related odors and taste in the emergence and maintenance of AD. This study thus investigated chemosensory impairments in AD and KS. Olfactory-gustatory measures were taken among 20 KS, 20 AD, and 20 control participants. Olfaction (odor detection-discrimination-identification) was assessed using the "Sniffin Sticks" battery and taste was measured using the "Taste Strips" task. Impairments were found for high-level olfaction in AD (odor discrimination) and KS (odor discrimination-identification), even after controlling for psychopathological comorbidities. Gustatory deficits were also observed in both groups, indexing a global deficit for chemosensory perception. Finally, the gradient of impairment between the successive disease stages for odor identification suggests that the hypothesis of a continuum between AD and KS regarding cognitive deficits can be generalized to chemosensory perception. AD and KS are thus characterized by deficits in chemosensory abilities, which could constitute a marker of the AD-KS transition. In view of its deleterious influence on everyday life, chemosensory dysfunction should also be taken into account in clinical settings.

PMID: 26354933 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1X0uK1C

The Insect Chemoreceptor Superfamily Is Ancient in Animals.

Related Articles

The Insect Chemoreceptor Superfamily Is Ancient in Animals.

Chem Senses. 2015 Nov;40(9):609-14

Authors: Robertson HM

Abstract
The insect chemoreceptor superfamily consists of 2 gene families, the highly diverse gustatory receptors (GRs) found in all arthropods with sequenced genomes and the odorant receptors that evolved from a GR lineage and have been found only in insects to date. Here, I describe relatives of the insect chemoreceptor superfamily, specifically the basal GR family, in diverse other animals, showing that the superfamily dates back at least to early animal evolution. GR-Like (GRL) genes are present in the genomes of the placozoan Trichoplax adhaerens, an anemone Nematostella vectensis, a coral Acropora digitifera, a polychaete Capitella teleta, a leech Helobdella robusta, the nematode Caenorhabditis elegans (and many other nematodes), 3 molluscs (a limpet Lottia gigantea, an oyster Crassostrea gigas, and the sea hare Aplysia californica), the sea urchin Strongylocentrotus purpuratus, and the sea acorn Saccoglossus kowalevskii. While some of these animals contain multiple divergent GRL lineages, GRLs have been lost entirely from other animal lineages such as vertebrates. GRLs are absent from the ctenophore Mnemiopsis leidyi, the demosponge Amphimedon queenslandica, and 2 available chaonoflagellate genomes, so it remains unclear whether this superfamily originated before or during animal evolution.

PMID: 26354932 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1OJph9u

Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

Related Articles

Acoustic shadows help gleaning bats find prey, but may be defeated by prey acoustic camouflage on rough surfaces.

Elife. 2015;4

Authors: Clare EL, Holderied MW

Abstract
Perceptual abilities of animals, like echolocating bats, are difficult to study because they challenge our understanding of non-visual senses. We used novel acoustic tomography to convert echoes into visual representations and compare these cues to traditional echo measurements. We provide a new hypothesis for the echo-acoustic basis of prey detection on surfaces. We propose that bats perceive a change in depth profile and an 'acoustic shadow' cast by prey. The shadow is more salient than prey echoes and particularly strong on smooth surfaces. This may explain why bats look for prey on flat surfaces like leaves using scanning behaviour. We propose that rather than forming search images for prey, whose characteristics are unpredictable, predators may look for disruptions to the resting surface (acoustic shadows). The fact that the acoustic shadow is much fainter on rougher resting surfaces provides the first empirical evidence for 'acoustic camouflage' as an anti-predator defence mechanism.

PMID: 26327624 [PubMed - indexed for MEDLINE]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/24KDT0N

Daphnia magna's sense of competition: intra-specific interactions (ISI) alter life history strategies and increase metals toxicity.

Daphnia magna's sense of competition: intra-specific interactions (ISI) alter life history strategies and increase metals toxicity.

Ecotoxicology. 2016 May 5;

Authors: Gust KA, Kennedy AJ, Melby NL, Wilbanks MS, Laird J, Meeks B, Muller EB, Nisbet RM, Perkins EJ

Abstract
This work investigates whether the scale-up to multi-animal exposures that is commonly applied in genomics studies provides equivalent toxicity outcomes to single-animal experiments of standard Daphnia magna toxicity assays. Specifically, we tested the null hypothesis that intraspecific interactions (ISI) among D. magna have neither effect on the life history strategies of this species, nor impact toxicological outcomes in exposure experiments with Cu and Pb. The results show that ISI significantly increased mortality of D. magna in both Cu and Pb exposure experiments, decreasing 14 day LC50 s and 95 % confidence intervals from 14.5 (10.9-148.3) to 8.4 (8.2-8.7) µg Cu/L and from 232 (156-4810) to 68 (63-73) µg Pb/L. Additionally, ISI potentiated Pb impacts on reproduction eliciting a nearly 10-fold decrease in the no-observed effect concentration (from 236 to 25 µg/L). As an indication of environmental relevance, the effects of ISI on both mortality and reproduction in Pb exposures were sustained at both high and low food rations. Furthermore, even with a single pair of Daphnia, ISI significantly increased (p < 0.05) neonate production in control conditions, demonstrating that ISI can affect life history strategy. Given these results we reject the null hypothesis and conclude that results from scale-up assays cannot be directly applied to observations from single-animal assessments in D. magna. We postulate that D. magna senses chemical signatures of conspecifics which elicits changes in life history strategies that ultimately increase susceptibility to metal toxicity.

PMID: 27151402 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1UHaaTE

Daphnia magna's sense of competition: intra-specific interactions (ISI) alter life history strategies and increase metals toxicity.

Daphnia magna's sense of competition: intra-specific interactions (ISI) alter life history strategies and increase metals toxicity.

Ecotoxicology. 2016 May 5;

Authors: Gust KA, Kennedy AJ, Melby NL, Wilbanks MS, Laird J, Meeks B, Muller EB, Nisbet RM, Perkins EJ

Abstract
This work investigates whether the scale-up to multi-animal exposures that is commonly applied in genomics studies provides equivalent toxicity outcomes to single-animal experiments of standard Daphnia magna toxicity assays. Specifically, we tested the null hypothesis that intraspecific interactions (ISI) among D. magna have neither effect on the life history strategies of this species, nor impact toxicological outcomes in exposure experiments with Cu and Pb. The results show that ISI significantly increased mortality of D. magna in both Cu and Pb exposure experiments, decreasing 14 day LC50 s and 95 % confidence intervals from 14.5 (10.9-148.3) to 8.4 (8.2-8.7) µg Cu/L and from 232 (156-4810) to 68 (63-73) µg Pb/L. Additionally, ISI potentiated Pb impacts on reproduction eliciting a nearly 10-fold decrease in the no-observed effect concentration (from 236 to 25 µg/L). As an indication of environmental relevance, the effects of ISI on both mortality and reproduction in Pb exposures were sustained at both high and low food rations. Furthermore, even with a single pair of Daphnia, ISI significantly increased (p < 0.05) neonate production in control conditions, demonstrating that ISI can affect life history strategy. Given these results we reject the null hypothesis and conclude that results from scale-up assays cannot be directly applied to observations from single-animal assessments in D. magna. We postulate that D. magna senses chemical signatures of conspecifics which elicits changes in life history strategies that ultimately increase susceptibility to metal toxicity.

PMID: 27151402 [PubMed - as supplied by publisher]

from #ΓεύσηΌσφρηση via xlomafota13 on Inoreader http://ift.tt/1UHaaTE