A Missing Piece of Occupational Therapy Education: Attitudes About Sex.

Following a lecture on sexual health and function, occupational therapy students were surveyed regarding their past sex education and their comfort level with the topic of sex. Students indicated a lack of sexual education received from parents/guardians and a prevalence of fear-based education from formal or informal sources. Results reflected a significant increase in students' perceived comfort level with the topic following the lecture from a provider trained and certified in sexual health. As sexuality falls within the domain of occupational therapy, these results suggest a need for comprehensive sex education taught to students by qualified instructors.

Recognizing Taste: Coding Patterns Along the Neural Axis in Mammals.

The gustatory system encodes information about chemical identity, nutritional value, and concentration of sensory stimuli before transmitting the signal from taste buds to central neurons that process and transform the signal. Deciphering the coding logic for taste quality requires examining responses at each level along the neural axis-from peripheral sensory organs to gustatory cortex. From the earliest single-fiber recordings, it was clear that some afferent neurons respond uniquely and others to stimuli of multiple qualities. There is frequently a "best stimulus" for a given neuron, leading to the suggestion that taste exhibits "labeled line coding." In the extreme, a strict "labeled line" requires neurons and pathways dedicated to single qualities (e.g., sweet, bitter, etc.). At the other end of the spectrum, "across-fiber," "combinatorial," or "ensemble" coding requires minimal specific information to be imparted by a single neuron. Instead, taste quality information is encoded by simultaneous activity in ensembles of afferent fibers. Further, "temporal coding" models have proposed that certain features of taste quality may be embedded in the cadence of impulse activity. Taste receptor proteins are often expressed in nonoverlapping sets of cells in taste buds apparently supporting "labeled lines." Yet, taste buds include both narrowly and broadly tuned cells. As gustatory signals proceed to the hindbrain and on to higher centers, coding becomes more distributed and temporal patterns of activity become important. Here, we present the conundrum of taste coding in the light of current electrophysiological and imaging techniques at several levels of the gustatory processing pathway.

Overlapping Representation of Primary Tastes in a Defined Region of the Gustatory Cortex.

Both physiological and imaging approaches have led to often-disparate conclusions about the organization of taste information in gustatory cortex (GC). In this study, we used neuroanatomical and imaging approaches to delineate the likely area of insular cortex given to gustatory function and to characterize taste responses within this delineated area in female and male C57BL/6J mice. Anterograde tracers were injected into the taste thalamus (the medial parvicellular portion of the ventral posterior medial division, VPMpc) of mice and the thalamic terminal field was investigated across the cortex. Working within the delineated area, we used two-photon imaging to measure basic taste responses in >780 neurons in layer 2/3 located just posterior to the middle cerebral artery. A nonbiased, hierarchical cluster analysis revealed multiple clusters of cells responding best to either individual or combinations of taste stimuli. Taste quality was represented in the activity of taste-responsive cells; however, there was no apparent spatial organization of primary taste qualities in this region.SIGNIFICANCE STATEMENT Recent studies investigating taste coding within the gustatory cortex have reported highly segregated, taste-specific regions containing only narrowly tuned cells responding to a single taste separated by large non-taste-coding areas. However, focusing on the center of this area, we found a large number of taste responsive cells ranging from narrowly to broadly responsive with no apparent local spatial organization. Further, population analysis reveals that activity in the neuronal population in this area appears to be related to measures of taste quality or hedonics.

Mice perceive synergistic umami mixtures as tasting sweet.

Previous electrophysiological investigation shows that combinations of compounds classified by humans as umami-tasting, such as glutamate salts and 5'-ribonucleotides, elicit synergistic responses in neurons throughout the rodent taste system and produce a pattern that resembles responses to sweet compounds. The current study tested the hypothesis that a synergistic mixture of monopotassium glutamate (MPG) and inositol monophosphate (IMP) possesses perceptual similarity to sucrose in mice. We estimated behavioral similarity among these tastants and the individual umami compounds using a series of conditioned taste aversion (CTA) tests, a procedure that measures whether a CTA formed to one stimulus generalizes to another. Our primary finding was that a CTA to a synergistic mixture of MPG + IMP generalizes to sucrose, and vice-versa. This indicates umami synergistic mixtures are perceived as having a sweet, or at least sucrose-like, taste to mice. Considering other recent studies, our data argue strongly in favor of multiple receptor mechanisms for umami detection, and complexity in taste perception models for rodents.

Head and Neck Ultrasound Utilization Rates: 2012 to 2019.

Objective: We measured utilization of clinician-performed head and neck ultrasound among otolaryngologists, endocrinologists, and general surgeons, using Medicare Provider Utilization and Payment Data. Study Design: Retrospective analysis of Medicare billing database. Setting: University. Methods: For each year, the files were filtered to include 4 provider types: Diagnostic Radiology (DR), Endocrinology (ENDO), General Surgery (GS), and Otolaryngology (OTO). Billable procedures are listed by Healthcare Common Procedure Coding System code and a filter was applied to include 76536 Ultrasound, soft tissues of the head and neck. Results: In 2019, OTOs submitted charges for 2.1% of all head and neck diagnostic ultrasounds (76536) performed on Medicare beneficiaries. For each year 2012 to 2019, DRs submitted the most charges, followed by ENDOs, and then OTO and GS. Charges for all groups increased in a proportional manner across the 8-year period. 14.5% of OTOs submitted more than 100 charges apiece during 2019, that is, "super users." The percentage of super users within each specialty increased from 2012 to 2019. Overall, the data support an ever-increasing use of head and neck ultrasound (HNUS) among all provider types. Conclusion: Even with increased use among OTOs, this specialty only accounted for a small percentage of head & neck diagnostic ultrasounds performed on Medicare beneficiaries in 2019. Changes in volume of nonradiology point-of-care HNUS was not associated with changes in DR volume. A greater proportion of OTOs than DRs are "super users" among the ultrasound users within their specialty, performing more than 100 exams/year. Level of Evidence: V.

Sweet-bitter and umami-bitter taste interactions in single parabrachial neurons in C57BL/6J mice.

We investigated sweet-bitter and umami-bitter mixture taste interactions by presenting sucrose or umami stimuli mixed with quinine hydrochloride (QHCl) while recording single-unit activity of neurons in the parabrachial nucleus (PbN) of urethane-anesthetized C57BL/6J mice. A total of 70 taste-responsive neurons were classified according to which stimulus evoked the greatest net response (36 sucrose-best, 19 NaCl-best, 6 citric acid-best, and 9 QHCl-best). Although no neurons responded best to monopotassium glutamate (MPG) or inosine 5'-monophosphate (IMP), the combination of these two stimuli evoked a synergistic response (i.e., response > 120% of the sum of the component responses) in all sucrose-best and some NaCl-best neurons (n = 43). Adding QHCl to sucrose or MPG + IMP resulted in suppression of the response (responses to mixture < responses to the more effective component) in 41 of 43 synergistic neurons. Neurons showing QHCl suppression were classified into two types: an "MS1" type (n = 27) with suppressed responses both to sucrose and MPG + IMP and an "MS2" type (n = 14) that showed suppressed responses only to sucrose. No neuron displayed suppressed responses to MPG or IMP alone. The suppression ratio (1 - mixture response/sucrose or MPG + IMP response) of sucrose and MPG + IMP in MS1 neurons had a weak positive correlation (r = 0.36). The pattern of reconstructed recording sites of neuron types suggested chemotopic organization in the PbN. Although a peripheral basis for QHCl suppression has been demonstrated, our results suggest that convergence in the PbN plays a role in shaping responses to taste mixtures.

Gustatory neural responses to umami stimuli in the parabrachial nucleus of C57BL/6J mice.

Umami is considered to be the fifth basic taste quality and is elicited by glutamate. The mouse is an ideal rodent model for the study of this taste quality because of evidence that suggests that this species, like humans, may sense umami-tasting compounds as unique from other basic taste qualities. We performed single-unit recording of taste responses in the parabrachial nucleus (PbN) of anesthetized C57BL/6J mice to investigate the central representation of umami taste. A total of 52 taste-responsive neurons (22 sucrose-best, 19 NaCl-best, 5 citric acid-best, and 6 quinine-best) were recorded from stimulation period with a large panel of basic and umami-tasting stimuli. No neuron responded best to monopotassium glutamate (MPG) or inosine 5'-monophosphate (IMP), suggesting convergence of input in the central nervous system. Synergism induced by an MPG-IMP mixture was observed in all sucrose-best and some NaCl-best neurons that possessed strong sensitivity to sucrose. In more than half of sucrose-best neurons, the MPG-IMP mixture evoked stronger responses than those elicited by their best stimulus. Furthermore, hierarchical cluster analysis and multidimensional analysis indicated close similarity between sucrose and the MPG-IMP mixture. These results strongly suggest the mixture tastes sweet to mice, a conclusion consistent with previous findings that show bidirectional generalization of conditioned taste aversion between sucrose and umami mixtures, and suppression of taste responses to both sucrose and mixtures by the antisweet polypeptide gurmarin in the chorda tympani nerve. The distribution pattern of reconstructed recording sites of specific neuron types suggested chemotopic organization in the PbN.

The impact of familiarity on cortical taste coding.

The role of the gustatory region of the insular cortex in mediating associative taste learning, such as conditioned taste aversion, has been well studied. However, while associative learning plays a role in some taste behaviors, such as avoiding toxins, animals often encounter taste stimuli in their natural environment without explicit consequences. This type of inconsequential experience with sensory stimuli has been studied in other sensory systems, generally with the finding that neuronal responses habituate with repeated sensory exposure. This study sought to determine the effect of taste familiarity on population taste coding in the mouse gustatory cortex (GC). Using microendoscope calcium imaging, we studied the taste responses of visually identifiable neurons over 5 days of taste experience, during which animals could freely choose to consume taste stimuli. We found that the number of active cells in the insular cortex, as well as the number of cells characterized as taste-responsive, significantly decreased as animals became familiar with taste stimuli. Moreover, the magnitude of taste-evoked excited responses increased while inhibited responses decreased with experience. By tracking individual neurons over time, we identified a subpopulation of stable neurons present on all days of the taste familiarity paradigm and further characterized their taste coding properties. The population-level response across these stable cells was distinct for each taste quality when taste stimuli were novel, but population responses for readily consumed stimuli became more correlated as the stimuli became familiar. Overall, these results highlight the effects of familiarity on both taste-specific and non-taste responses in the gustatory cortex.

Decrease in sweet taste in rats after gastric bypass surgery.

BACKGROUND: The literature contains evidence that Roux-en-Y gastric bypass (RYGB) surgery has an effect in humans on taste and preference for carbohydrate-rich foods. This study tested the hypothesis that RYGB affects sweet taste behavior using a rat model. METHODS: Male Sprague-Dawley rats underwent either RYGB or sham surgery. Then 4 weeks after surgery, the rats were given taste-salient, brief-access lick tests with a series of sucrose concentrations. RESULTS: The RYGB rats, but not the sham rats, lost weight over the 5-week postoperative period. The RYGB rats showed a significant decrease in mean licks for the highest concentration of sucrose (0.25-1.0 mol/l) but not for the low concentrations of sucrose or water. CONCLUSIONS: The findings showed that RYGB surgery affected sweet taste behavior in rats, with postsurgical rats having lower sensitivity or avidity for sucrose than sham-treated control rats. This finding is similar to human reports that sweet taste and preferences for high-caloric foods are altered after bypass surgery.

Rethinking the role of taste processing in insular cortex and forebrain circuits.

Over the years, many approaches towards studying the taste-responsive area of insular cortex have focused on how basic taste information is represented, and how lesions or silencing of this area impact taste-focused behaviors. Here, we review and highlight recent studies that imply that insular cortex does not contain a "primary" taste cortex in the traditional sense. Rather, taste is employed in concert with other internal and external sensory modalities by highly interconnected regions of insular cortex to guide ingestive decision-making, especially in context of estimating risk and reward. In rodent models, this may best be seen in context of foraging behaviors, which require flexibility and are dependent on learning and memory processes.

Quality of life in obese patients after thyroidectomy for goiter.

BACKGROUND: Compressive symptoms are common in thyroid disease. Many studies have focused on the size of the gland and its effects on patients. However, few have taken into account the body mass of the patient. The aim of our study was to examine whether or not a patient's body mass index (BMI) influences symptomatic outcomes following thyroid surgery for benign disease. METHODS: We conducted a prospective analysis evaluating 60 patients that underwent thyroidectomy for benign goiter (single or multinodular) disease. Patients were classified as obese, overweight, or normal based on BMI. Pre- and post-operative surveys were administered including the MRC breathlessness scale, M.D. Anderson Dysphagia Inventory (MDADI), and the ThyPRO quality of life questionnaire to evaluate dysphagia, dyspnea, and quality of life respectively. RESULTS: Patients classified as obese (n=37) scored significantly worse pre-operatively on MRC, MDADI, and ThyPRO surveys when compared to overweight (n=13) or normal weight (n=10) counterparts. Subjects in the obese group, but not the other groups, showed post-surgical improvement on both the MRC and MDADI surveys (P<0.0001). Similarly, obese subjects showed significant improvement on all 11 domains of the ThyPRO survey following surgery (P<0.0001), and overall degree of improvement was highly correlated with BMI among all subjects (r=0.60; P=0.0005). CONCLUSIONS: Obesity, as determined by BMI, is a critical factor to consider in the alleviation of compressive symptoms before and after thyroidectomy for goiter. Our analysis of survey data indicates obese subjects have increased benefit of surgery compared to their lighter counterparts.

Cerebellar cortical output encodes temporal aspects of rhythmic licking movements and is necessary for normal licking frequency.

Rodents consume water by performing stereotypic, rhythmic licking movements that are believed to be controlled by brainstem pattern-generating circuits. Previous work has shown that synchronized population activity of inferior olive neurons was phase-locked to the licking rhythm in rats, suggesting a cerebellar involvement in temporal aspects of licking behavior. However, what role the cerebellum has in licking behavior and whether licking is represented in the high-frequency simple spike output of Purkinje cells remains unknown. We recorded Purkinje cell simple and complex spike activity in awake mice during licking, and determined the behavioral consequences of loss of cerebellar function. Mouse cerebellar cortex contained a multifaceted representation of licking behavior encoded in the simple spike activities of Purkinje cells distributed across Crus I, Crus II and lobus simplex of the right cerebellar hemisphere. Lick-related Purkinje cell simple spike activity was modulated rhythmically, phase-locked to the lick rhythm, or non-rhythmically. A subpopulation of lick-related Purkinje cells differentially represented lick interval duration in their simple spike activity. Surgical removal of the cerebellum or temporary pharmacological inactivation of the cerebellar nuclei significantly slowed the licking frequency. Fluid licking was also less efficient in mice with impaired cerebellar function, indicated by a significant decline in the volume per lick fluid intake. The gross licking movement appeared unaffected. Our results suggest a cerebellar role in modulating the frequency of the central pattern-generating circuits controlling fluid licking and in the fine coordination of licking, while contributing little to the coordination of the gross licking movement.

Variation in nicotine consumption in inbred mice is not linked to orosensory ability.

Genetic studies of nicotine addiction in mice have utilized the oral self-administration model. However, it is unclear if strain differences in nicotine consumption are influenced by variation in bitter taste sensitivity. We measured both nicotine consumption and nicotine brief-access licking behavior in several commonly used inbred strains of mice that were previously shown to differ in nicotine consumption. A/J (A), C57BL/6J (B6), and DBA/2J (D2) mice were given a 2-bottle choice test with a single concentration of nicotine (75 microg/ml; nicotine vs. water). Mice of these strains were also tested with a range of nicotine concentrations (5-400 microg/ml) using a brief-access test, which measures orosensory response and minimizes postingestive effects. Although B6 mice consumed more 75-microg/ml nicotine than A or D2 mice in the 2-bottle test, these strains did not differ in level of aversion to nicotine when tested with the brief-access procedure. Strain differences in orosensory response to nicotine were not found; yet, differences emerged during the 2-bottle tests. This study provides evidence that variation in intake level of nicotine is likely not due to differences in taste or trigeminal sensitivity but likely due to postingestive factors.

Orosensory responsiveness to and preference for hydroxide-containing salts in mice.

Historically, taste researchers have considered the possibility that the gustatory system detects basic compounds, such as those containing the hydroxide ion, but evidence for an "alkaline taste" has not been strong. We found that, in 48 h, 2-bottle preference tests, C3HeB/FeJ (C3) mice showed a preference for Ca(OH)(2), whereas SWR/J (SW) mice showed avoidance. Strain differences were also apparent to NaOH but not CaCl(2). Follow-up studies showed that the strain difference for Ca(OH)(2) was stable over time (Experiment 2) but that C3 and SW mice did not differ in their responses to Ca(OH)(2) or NaOH in brief-access tests, where both mice avoided high concentrations of these compounds (Experiment 3). In order to assess the perceived quality of Ca(OH)(2), mice were tested in 2 taste aversion generalization experiments (Experiments 4 and 5). Aversions to Ca(OH)(2) generalized to NaOH but not CaCl(2) in both strains, suggesting that the generalization was based on the hydroxide ion. Both strains also generalized aversions to quinine, suggesting the possibility that the hydroxide ion has a bitter taste quality to these mice, despite the preference shown by C3 mice to middle concentrations in long-term tests.

Sweet and bitter taste stimuli activate VTA projection neurons in the parabrachial nucleus.

This study investigated neural projections from the parabrachial nucleus (PBN), a gustatory and visceral processing area in the brainstem, to the ventral tegmental area (VTA) in the midbrain. The VTA contains a large population of dopaminergic neurons that have been shown to play a role in reward processing. Anterograde neural tracing methods were first used to confirm that a robust projection from the caudal PBN terminates in the dorsal VTA; this projection was larger on the contralateral side. In the next experiment, we combined dual retrograde tracing from the VTA and the gustatory ventral posteromedial thalamus (VPMpc) with taste-evoked Fos protein expression, which labels activated neurons. Mice were stimulated through an intraoral cannula with sucrose, quinine, or water, and PBN sections were processed for immunofluorescent detection of Fos and retrograde tracers. The distribution of tracer-labeled PBN neurons demonstrated that the populations of cells projecting to the VTA or VPMpc are largely independent. Quantification of cells double labeled for Fos and either tracer demonstrated that sucrose and quinine were effective in activating both pathways. These results indicate that information about both appetitive and aversive tastes is delivered to a key midbrain reward interface via direct projections from the PBN.

The effect of intrathyroidal versus intraperitoneal bevacizumab on thyroid volume and vasculature flow in a rat model.

BACKGROUND: Several clinical conditions increase thyroid gland vascularity, impacting surgical blood loss. Bevacizumab has been observed to reduce thyroid function, possibly through its effect on gland angiogenesis. This study aimed to determine if bevacizumab has any effect on thyroid vascularity as measured by gland volume and superior thyroid artery (STA) flow velocity in the normal rat thyroid. METHODS: Sixteen adult female Sprague-Dawley rats were placed under general anesthesia to measure baseline thyroid gland characteristics. A Vevo 2100 high-frequency ultrasound with 40 mHz transducer was used to obtain STA flow measurements and thyroid gland dimensions. Four rats served as controls. Six rats received intrathyroidal (IT) injections and 6 received intraperitoneal (IP) injections of bevacizumab (4-5 mg/kg). After two weeks ultrasound measurements were repeated. RESULTS: Pretreatment animals displayed similar thyroid volume and vascularity. Thyroid volume decreased (62.583 vs. 42.161, P=0.004) after IP administration of bevacizumab, and blood flow measurements did not change [peak velocity 75.896 vs. 76.7, P=0.96, average velocity 45.748 vs. 43.867, P=0.88, or resistivity index (RI) 30.345 vs. 25.32, P=0.60]. IT bevacizumab did not change thyroid volume (55.229 vs. 58.16, P=0.64). The average peak (73.191 vs. 100.589 cm/s, P=0.03) and mean (45.047 vs. 62.843 m/s, P=0.03) velocities were increased, but did not differ in the RI (0.619 vs. 0.632, P=0.82). No differences were noted on VEGF or CD 31 immunohistochemical analysis. CONCLUSIONS: Single systemic administration of bevacizumab appears to decrease thyroid volume without an effect on STA flow, VEGF or CD31 staining. These preliminary findings support further study of pharmacologic intervention in thyroid conditions characterized by increased angiogenesis and vascularity, such as iodine deficiency, Graves disease, and hypothyroidism.

Gastric bypass surgery in rats produces weight loss modeling after human gastric bypass.

BACKGROUND: The study of the mechanisms of weight loss after bariatric surgery requires an animal model that mimics the human procedure and subsequent weight loss. A rat model eliminates the cognitive efforts associated with human weight loss and gain. METHODS: A technique for gastric bypass (Roux-en-Y gastric bypass [RYGB]) was developed in Sprague-Dawley rats. A 1- to 2-cc pouch is created from the uppermost stomach using a linear stapler. A 10-cm biliopancreatic limb and 15-cm Roux limb are anastomosed side to side with running nonabsorbable suture. The gastrojejunostomy is created with a single layer of running nonabsorbable suture. Four rats underwent RYGB. Weight loss was compared to four sham rats that had a midline incision and left 60 min with an open abdomen before closure. RESULTS: RYGB rats lost an average of 16.5% body weight (BW) at 1 week, 22% BW at 2 weeks, 20% BW at 3 weeks, and 11% BW at 4 weeks. The RYGB rat's weight was basically level after 4 weeks. The shams lost an average of 4% BW at 1 week, 1% BW at 2 weeks, and 0% BW at 3 weeks and gained an average of 2% at weeks. Subjectively, the RYGB rats were less interested in chow and frequently had chow left in their cage. CONCLUSION: A Sprague-Dawley rat model for gastric bypass has been developed and yields approximately 11% BW loss. This will allow investigators to objectively view factors associated with weight loss without the confounding cognitive factors in humans.

Genetic analysis of tongue size and taste papillae number and size in recombinant inbred strains of mice.

Quantitative trait loci (QTLs) analysis has been used to examine natural variation of phenotypes in the mouse somatosensory cortex, hippocampus, cerebellum, and amygdala. QTL analysis has also been utilized to map and identify genes underlying anatomical features such as muscle, organ, and body weights. However, this methodology has not been previously applied to identification of anatomical structures related to gustatory phenotypes. In this study, we used QTL analysis to map and characterize genes underlying tongue size, papillae number, and papillae area. In a set of 43 BXD recombinant inbred (RI) mice (n = 111) and 2 parental strains (C57BL/6J and DBA/2J; n = 7), we measured tongue length, width, and weight. In a subset of 23 BXD RI mice and the parental mice, we measured filiform and fungiform papillae number and fungiform papillae area. Using QTL linkage analysis (through WebQTL), we detected 2 significant and noninteracting QTLs influencing tongue length on chromosomes 5 and 7. We also found a significant QTL on chromosome 19 underlying fungiform papillae area and a suggestive QTL on chromosome 2 linked to fungiform papillae number. From these QTLs, we identified a number of candidate genes within the QTL intervals that include SRY-box containing gene, nebulin-related anchoring protein, and actin-binding LIM protein 1. This study is an important first step in identifying genetic factors underlying tongue size, papillae size, and papillae number using QTL analysis.

Validation of ultrasound as a diagnostic tool to assess vocal cord motion in an animal feasibility study.

BACKGROUND: Post-thyroidectomy dysphonia can result from recurrent laryngeal nerve (RLN) injury. Confirmation of postoperative recurrent nerve function has prompted many surgeons to advocate laryngoscopic examination. Indirect and flexible laryngoscopy permit visualization of vocal cord motion, but not all thyroid surgeons are skilled in these techniques. Indirect laryngoscopy has a significant failure rate due to gag reflexes or anatomical obstruction. Flexible fiberoptic laryngoscopy, the current gold standard, allows reliable visualization of the cords, but perioperative examination is not always feasible for lack of equipment or training. Recent studies suggest vocal fold ultrasound as an alternative to flexible laryngoscopy. It offers the advantages of being non-invasive and painless without radiation exposure or sedation. Whereas ultrasound has been compared to laryngoscopy in the clinical setting, there remains a need for correlation of laryngeal ultrasound results with known neurophysiology in the normal and injured state. An animal model was proposed that reproduces neck surgery-associated recurrent nerve injury. The model allowed simultaneous recording of laryngeal endoscopy and transcutaneous high-resolution ultrasound during stimulation of intact and injured RLNs. METHODS: One RLN was injured in each of 4 rats. Rats were kept anesthetized during the fiberoptic examination and laryngeal ultrasound procedures. Following surgery and subsequent imaging the rats were given a lethal anesthetic dose. Results of both imaging modalities were compared to the presence or absence of neuromuscular action potential following stimulation of the recurrent nerve. RESULTS: The investigators observed a 100% correlation between endoscopic and ultrasonographic assessments. CONCLUSIONS: This study validated the clinical use of diagnostic ultrasound in vocal cord dysfunction in a rodent model.

Behavioral genetics and taste.

This review focuses on behavioral genetic studies of sweet, umami, bitter and salt taste responses in mammals. Studies involving mouse inbred strain comparisons and genetic analyses, and their impact on elucidation of taste receptors and transduction mechanisms are discussed. Finally, the effect of genetic variation in taste responsiveness on complex traits such as drug intake is considered. Recent advances in development of genomic resources make behavioral genetics a powerful approach for understanding mechanisms of taste.