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Alan C. Spector - One of the best experts on this subject based on the ideXlab platform.
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extensive lesions in rat insular cortex significantly disrupt Taste sensitivity to nacl and kcl and slow salt Discrimination learning
PLOS ONE, 2015Co-Authors: Ginger D. Blonde, Michelle B Bales, Alan C. SpectorAbstract:While studies of the gustatory cortex (GC) mostly focus on its role in Taste aversion learning and memory, the necessity of GC for other fundamental Taste-guided behaviors remains largely untested. Here, rats with either excitotoxic lesions targeting GC (n = 26) or sham lesions (n = 14) were assessed for postsurgical retention of a presurgically LiCl-induced conditioned Taste aversion (CTA) to 0.1M sucrose using a brief-access Taste generalization test in a gustometer. The same animals were then trained in a two-response operant Taste detection task and psychophysically tested for their salt (NaCl or KCl) sensitivity. Next, the rats were trained and tested in a NaCl vs. KCl Taste Discrimination task with concentrations varied. Rats meeting our histological inclusion criterion had large lesions (resulting in a group averaging 80% damage to GC and involving surrounding regions) and showed impaired postsurgical expression of the presurgical CTA (LiCl-injected, n = 9), demonstrated rightward shifts in the NaCl (0.54 log10 shift) and KCl (0.35 log10 shift) psychometric functions, and displayed retarded salt Discrimination acquisition (n = 18), but eventually learned and performed the Discrimination comparable to sham-operated animals. Interestingly, the degree of deficit between tasks correlated only modestly, if at all, suggesting that idiosyncratic differences in insular cortex lesion topography were the root of the individual differences in the behavioral effects demonstrated here. This latter finding hints at some degree of interanimal variation in the functional topography of insular cortex. Overall, GC appears to be necessary to maintain normal Taste sensitivity to NaCl and KCl and for salt Discrimination learning. However, higher salt concentrations can be detected and discriminated by rats with extensive damage to GC suggesting that the other resources of the gustatory system are sufficient to maintain partial competence in these tasks, supporting the view that such basic sensory-discriminative Taste functions involve distributed processes among central gustatory structures.
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Learning-based recovery from perceptual impairment in salt Discrimination after permanently altered peripheral gustatory input
American journal of physiology. Regulatory integrative and comparative physiology, 2010Co-Authors: Ginger D. Blonde, Enshe Jiang, Mircea Garcea, Alan C. SpectorAbstract:Rats lacking input to the chorda tympani (CT) nerve, a facial nerve branch innervating anterior tongue Taste buds, show robust impairments in salt Discrimination demonstrating its necessity. We tested the sufficiency of the CT for salt Taste Discrimination and whether the remaining input provided by the greater superficial petrosal (GSP) nerve, a facial nerve branch innervating palatal Taste buds, or by the glossopharyngeal (GL) nerve, innervating posterior tongue Taste buds, could support performance after extended postsurgical testing. Rats presurgically trained and tested in a two-response operant task to discriminate NaCl from KCl were subjected to sham surgery or transection of the CT (CTx), GL (GLx), or GSP (GSPx), alone or in combination. While initially reduced postsurgically, performance by rats with an intact GSP after CTx + GLx increased to normal over 6 wk of testing. Rats with CTx + GSPx consistently performed near chance levels. In contrast, rats with GSPx + GLx were behaviorally normal. A subset of rats subjected to sham surgery and exposed to lower concentrations during postsurgical testing emulating decreased stimulus intensity after neurotomy showed no significant impairment. These results demonstrate that CTx changes the perceptual nature of NaCl and/or KCl, leading to severe initial postsurgical impairments in discriminability, but a “new” Discrimination can be relearned based on the input of the GSP. Despite losing ∼75% of their Taste buds, rats are unaffected after GSPx + GLx, demonstrating that the CT is not only necessary, but also sufficient, for maintaining salt Taste Discrimination, notwithstanding the unlikely contribution of the small percentage of Taste receptors innervated by the superior laryngeal nerve.
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rewiring the gustatory system specificity between nerve and Taste bud field is critical for normal salt Discrimination
Brain Research, 2010Co-Authors: Alan C. Spector, Ginger D. Blonde, Enshe Jiang, Mircea GarceaAbstract:Abstract Forty years have passed since it was demonstrated that a cross-regenerated gustatory nerve in the rat tongue adopts the stimulus–response properties of the Taste receptor field it cross-reinnervates. Nevertheless, the functional consequences of channeling peripheral Taste signals through inappropriate central circuits remain relatively unexplored. Here we tested whether histologically confirmed cross-regeneration of the chorda tympani nerve (CT) into the posterior tongue in the absence of the glossopharyngeal nerve (GL) (CT-PostTongue) or cross-regeneration of the GL into the anterior tongue in the absence of the CT (GL-AntTongue) would maintain presurgically trained performance in an operant NaCl vs. KCl Taste Discrimination task in rats. Before surgery all groups were averaging over 90% accuracy. Oral amiloride treatment dropped performance to virtually chance levels. During the first week after surgery, sham-operated rats, GL-transected rats, and rats with regenerated CTs displayed highly competent Discrimination performance. In contrast, CT-transected rats were severely impaired (59% accuracy). Both the CT-PostTongue and the GL-AntTongue groups were impaired to a similar degree as CT-transected rats. These initially impaired groups improved their performance over the weeks of postsurgical testing, suggesting that the rats were capable of relearning the task with discriminable signals in the remaining Taste nerves. This relearned performance was dependent on input from amiloride-sensitive receptors likely in the palate. Overall, these results suggest that normal competence in a salt Discrimination task is dependent on the Taste receptor field origin of the input as well as the specific nerve transmitting the signals to its associated circuits in the brain.
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Taste Discrimination between nacl and kcl is disrupted by amiloride in inbred mice with amiloride insensitive chorda tympani nerves
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2005Co-Authors: Shachar Eylam, Alan C. SpectorAbstract:The amiloride-sensitive salt transduction pathway is thought to be critical for the Discrimination between sodium and nonsodium salts in rodents. In rats, lingual application of amiloride appears t...
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the effect of amiloride on operantly conditioned performance in an nacl Taste detection task and nacl preference in c57bl 6j mice
Behavioral Neuroscience, 2002Co-Authors: Shachar Eylam, Alan C. SpectorAbstract:A 2-response operant Taste Discrimination procedure, modified to assess Taste sensitivity in water-restricted C57BL/6J mice, revealed a detection threshold of 0.065 M sodium chloride. Amiloride increased the threshold by approximately 1 log10 unit. These results are the first to demonstrate the necessity of the amiloride-sensitive Taste transduction pathway in the normal detection of low concentrations of sodium chloride in mice and provide a functional context in which to evaluate electrophysiological findings. Two-bottle preference tests performed with these mice and additional naive mice revealed only marginal, if any, effects of amiloride on salt intake behavior, highlighting the importance of considering the relative attributes and limitations of different behavioral assays of Taste function.
Hisashi Ogawa - One of the best experts on this subject based on the ideXlab platform.
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Neuronal activities in the monkey primary and higher-order gustatory cortices during a Taste Discrimination delayed GO/NOGO task and after reversal
Neuroscience Research, 2003Co-Authors: Hirotoshi Ifuku, Shin Ichi Hirata, Tamio Nakamura, Hisashi OgawaAbstract:Abstract The correlation between different gustatory areas in the frontal operculum, orbitofrontal area, and insula and the representation of different aspects of cues during a salt–water Discrimination delayed GO/NOGO task was studied in a Japanese monkey. Four groups were identified among 169 neurons responding to cues before/after task reversal. Group I ( n =78) responded to the physicochemical nature of the cue, Group II ( n =8) responded to both the physicochemical nature of the cue and the subsequent behavior, Group III ( n =51) (three subgroups) produced discharges related to the subsequent behavior, and Group IV ( n =32) produced non-differential responses probably related to attention. The primary gustatory areas (area G and the oral part of area 3) almost exclusively contained Group I neurons, whereas the so-called secondary gustatory areas (the PrCO and area 12) contained most of the Group III neurons. Group IIIc showed discharges accelerating to the LED onset, probably representing preparation for subsequent behavior, and the response differed between the PrCO and area 12. The PrCO also contained Group IV neurons. The primary gustatory areas process pure gustatory signals, whereas the PrCO and area 12 may be involved in gustatory perception, attention, or behavior.
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neuronal activity in the monkey fronto opercular and adjacent insular prefrontal cortices during a Taste Discrimination go nogo task response to cues
Neuroscience Research, 2001Co-Authors: Shinichi Ito, Hirotoshi Ifuku, Miki Ohgushi, Hisashi OgawaAbstract:Abstract The neural coding of Taste information in the fronto-opercular cortex (Fop) and the orbitofrontal area (OFA) was investigated by recording neural activities in monkeys performing a NaCl–water Discrimination GO/NOGO task. Responses to GO (NaCl) and NOGO cues (water) were recorded from 160 neurons, of which 118 differentially responded to two cues (differential, Dif neurons), and 42 showed the same response (non-differential, ND neurons). Differential neurons included equal numbers of GO- and NOGO-dominant subtypes. Dif and ND neurons may code for different cues, e.g., Taste and touch, as shown by our previous study [Jpn. J. Physiol. 44 (1994) 141]. The response latency of neurons in the exposed Fop was distributed with two modes, one at the shortest bin (100 ms) and one at the bin of 400–800 ms, but neurons in the buried Fop and OFA all had long latency. Such a difference between the two cortical groups of neurons suggests different roles in Taste Discrimination tasks. Most neurons did not show changes in the discharges or latency with varying concentrations of NaCl. The results indicate that neurons in the areas surveyed code for Taste information differently in the task-performing state compared with the non-behaving state examined in previous studies.
James H Woods - One of the best experts on this subject based on the ideXlab platform.
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further characterization of the quinine Taste Discrimination stimulus in rhesus monkeys effects of inter trial interval number and distribution of test stimuli
Behavioural Pharmacology, 1999Co-Authors: Jeffrey A Vivian, Tina L Sumpter, James H WoodsAbstract:: The purpose of the current investigation was to characterize further the Taste discriminative stimulus properties of quinine. Using a food-maintained two-choice (quinine and water) Discrimination paradigm, the effects of varying inter-trial intervals, and the number and distribution of test stimuli were examined in rhesus monkeys (Macaca mulatta). Monkeys were trained to respond under a chain schedule of reinforcement (FR5B-fluid, FR30B-food) with a 60-s inter-trial interval. Interestingly, the quinine Discrimination remained invariant across all the conditions tested: alterations in inter-trial interval (0, 15, 30, 45, 60 s), alterations in the number of test stimuli (six at quarter-log unit increments [0.1-1 mg/ml] versus 10 at quarter-log unit increments [0.01-1 mg/ml]), and alterations in the distribution of the test stimuli (quarter-log unit increments [0.1-0.1 mg/ml] versus half-log unit increments [0.01-1 mg/ml]) failed to alter the quinine discriminative stimulus (ED50s ranged from 0.18-0.29 mg/ml). Furthermore, incorrect lever selections were very rare (less than 12% of all test sessions), independent of test stimuli order (i.e. quinine followed by water trials, water followed by quinine trials), and independent of the progress through the test session (i.e. incorrect lever selections were consistent--approximately one error for every 10 trials--within early, middle and late portions of the session). These results demonstrate the reliability and robustness of the quinine Taste discriminative stimulus in rhesus monkeys and provide further validation for the experimental paradigm.
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training and characterization of a quinine Taste Discrimination in rhesus monkeys
Psychopharmacology, 1999Co-Authors: J Aspen, M B Gatch, James H WoodsAbstract:There is a limited amount of information available about Taste as a discriminative stimulus in non-human primates. The objective of this study was to establish a bitter Taste (quinine sulfate) as a cue for lever selection and food reward in rhesus monkeys. Training took place in a series of steps that culminated in a schedule in which five lip contacts on a spout produced either quinine solution or water, followed by an opportunity to earn a food pellet by completing 20 presses on one of two levers. Responses on one of the levers resulted in food delivery if the solution contained quinine; responses on the other lever resulted in food delivery if the solution was water. A single session consisted of 100 randomly ordered Taste trials with a 60-s interval between each trial. All of the animals acquired the Discrimination, and the lowest quinine concentration that maintained consistent behavior was 0.3 mg/ml. To assess the specificity of the Discrimination, compounds from other human Taste categories were tested. A series of compounds that are detected as "bitter" by humans (caffeine, 1.5x10(-3) M; strychnine, 9x10(-4) M; PTC, 6x10(-5) M, denatonium benzoate, 2.24x10(-4) M; and urea, 3.0x10(-1) M) produced full generalization to the quinine sulfate discriminative stimulus, while "sweet" (sucrose, 2.9x10(-2) M) and "salty" (sodium chloride, 1.4 M) stimuli did not. There was individual variation among animals in response to "sour" compounds; acetic acid did not generalize to quinine, but HCl acid produced full generalization in one of three animals. These results suggest that a "bitter" Taste cue is controlling the quinine Discrimination.
Ginger D. Blonde - One of the best experts on this subject based on the ideXlab platform.
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extensive lesions in rat insular cortex significantly disrupt Taste sensitivity to nacl and kcl and slow salt Discrimination learning
PLOS ONE, 2015Co-Authors: Ginger D. Blonde, Michelle B Bales, Alan C. SpectorAbstract:While studies of the gustatory cortex (GC) mostly focus on its role in Taste aversion learning and memory, the necessity of GC for other fundamental Taste-guided behaviors remains largely untested. Here, rats with either excitotoxic lesions targeting GC (n = 26) or sham lesions (n = 14) were assessed for postsurgical retention of a presurgically LiCl-induced conditioned Taste aversion (CTA) to 0.1M sucrose using a brief-access Taste generalization test in a gustometer. The same animals were then trained in a two-response operant Taste detection task and psychophysically tested for their salt (NaCl or KCl) sensitivity. Next, the rats were trained and tested in a NaCl vs. KCl Taste Discrimination task with concentrations varied. Rats meeting our histological inclusion criterion had large lesions (resulting in a group averaging 80% damage to GC and involving surrounding regions) and showed impaired postsurgical expression of the presurgical CTA (LiCl-injected, n = 9), demonstrated rightward shifts in the NaCl (0.54 log10 shift) and KCl (0.35 log10 shift) psychometric functions, and displayed retarded salt Discrimination acquisition (n = 18), but eventually learned and performed the Discrimination comparable to sham-operated animals. Interestingly, the degree of deficit between tasks correlated only modestly, if at all, suggesting that idiosyncratic differences in insular cortex lesion topography were the root of the individual differences in the behavioral effects demonstrated here. This latter finding hints at some degree of interanimal variation in the functional topography of insular cortex. Overall, GC appears to be necessary to maintain normal Taste sensitivity to NaCl and KCl and for salt Discrimination learning. However, higher salt concentrations can be detected and discriminated by rats with extensive damage to GC suggesting that the other resources of the gustatory system are sufficient to maintain partial competence in these tasks, supporting the view that such basic sensory-discriminative Taste functions involve distributed processes among central gustatory structures.
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Learning-based recovery from perceptual impairment in salt Discrimination after permanently altered peripheral gustatory input
American journal of physiology. Regulatory integrative and comparative physiology, 2010Co-Authors: Ginger D. Blonde, Enshe Jiang, Mircea Garcea, Alan C. SpectorAbstract:Rats lacking input to the chorda tympani (CT) nerve, a facial nerve branch innervating anterior tongue Taste buds, show robust impairments in salt Discrimination demonstrating its necessity. We tested the sufficiency of the CT for salt Taste Discrimination and whether the remaining input provided by the greater superficial petrosal (GSP) nerve, a facial nerve branch innervating palatal Taste buds, or by the glossopharyngeal (GL) nerve, innervating posterior tongue Taste buds, could support performance after extended postsurgical testing. Rats presurgically trained and tested in a two-response operant task to discriminate NaCl from KCl were subjected to sham surgery or transection of the CT (CTx), GL (GLx), or GSP (GSPx), alone or in combination. While initially reduced postsurgically, performance by rats with an intact GSP after CTx + GLx increased to normal over 6 wk of testing. Rats with CTx + GSPx consistently performed near chance levels. In contrast, rats with GSPx + GLx were behaviorally normal. A subset of rats subjected to sham surgery and exposed to lower concentrations during postsurgical testing emulating decreased stimulus intensity after neurotomy showed no significant impairment. These results demonstrate that CTx changes the perceptual nature of NaCl and/or KCl, leading to severe initial postsurgical impairments in discriminability, but a “new” Discrimination can be relearned based on the input of the GSP. Despite losing ∼75% of their Taste buds, rats are unaffected after GSPx + GLx, demonstrating that the CT is not only necessary, but also sufficient, for maintaining salt Taste Discrimination, notwithstanding the unlikely contribution of the small percentage of Taste receptors innervated by the superior laryngeal nerve.
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rewiring the gustatory system specificity between nerve and Taste bud field is critical for normal salt Discrimination
Brain Research, 2010Co-Authors: Alan C. Spector, Ginger D. Blonde, Enshe Jiang, Mircea GarceaAbstract:Abstract Forty years have passed since it was demonstrated that a cross-regenerated gustatory nerve in the rat tongue adopts the stimulus–response properties of the Taste receptor field it cross-reinnervates. Nevertheless, the functional consequences of channeling peripheral Taste signals through inappropriate central circuits remain relatively unexplored. Here we tested whether histologically confirmed cross-regeneration of the chorda tympani nerve (CT) into the posterior tongue in the absence of the glossopharyngeal nerve (GL) (CT-PostTongue) or cross-regeneration of the GL into the anterior tongue in the absence of the CT (GL-AntTongue) would maintain presurgically trained performance in an operant NaCl vs. KCl Taste Discrimination task in rats. Before surgery all groups were averaging over 90% accuracy. Oral amiloride treatment dropped performance to virtually chance levels. During the first week after surgery, sham-operated rats, GL-transected rats, and rats with regenerated CTs displayed highly competent Discrimination performance. In contrast, CT-transected rats were severely impaired (59% accuracy). Both the CT-PostTongue and the GL-AntTongue groups were impaired to a similar degree as CT-transected rats. These initially impaired groups improved their performance over the weeks of postsurgical testing, suggesting that the rats were capable of relearning the task with discriminable signals in the remaining Taste nerves. This relearned performance was dependent on input from amiloride-sensitive receptors likely in the palate. Overall, these results suggest that normal competence in a salt Discrimination task is dependent on the Taste receptor field origin of the input as well as the specific nerve transmitting the signals to its associated circuits in the brain.
Eugene R. Delay - One of the best experts on this subject based on the ideXlab platform.
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monosodium glutamate and sweet Taste Discrimination between the Tastes of sweet stimuli and glutamate in rats
Chemical Senses, 2004Co-Authors: Beth R Heyer, Carol C Taylorburds, Jeremiah D Mitzelfelt, Eugene R. DelayAbstract:Generalization of a conditioned Taste aversion (CTA) is based on similarities in Taste qualities shared by the aversive substance and another Taste substance. CTA experiments with rats have found that an aversion to a variety of sweet stimuli will crossgeneralize with monosodium glutamate (MSG) when amiloride, a sodium channel blocker, is added to all solutions to reduce the Taste of sodium. These findings suggest that the glutamate anion elicits a sweet Taste sensation in rats. CTA experiments, however, generally do not indicate whether two substances have different Taste qualities. In this study, Discrimination methods in which rats focused on perceptual differences were used to determine if they could distinguish between the Tastes of MSG and four sweet substances. As expected, rats readily discriminated between two natural sugars (sucrose, glucose) and two artificial sweeteners (saccharin, SC45647). Rats also easily discriminated between MSG and glucose, saccharin and, to a lesser extent, SC45647 when the Taste of the sodium ion of MSG was reduced by the addition of amiloride to all solutions, or the addition of amiloride to all solutions and NaCl to each sweet stimulus to match the concentration of Na + in the MSG solutions. In contrast, reducing the cue function of the Na+ ion significantly decreased their ability to discriminate between sucrose and MSG. These results suggest that the sweet qualities of glutamate Taste is not as dominate a component of glutamate Taste as CTA experiments suggest and these qualities are most closely related to the Taste qualities of sucrose. The findings of this study, in conjunction with other research, suggest that sweet and umami afferent signaling may converge through a Taste receptor with a high affinity for glutamate and sucrose or a downstream transduction mechanism. These data also suggest that rats do not necessarily perceive the Tastes of these sweet stimuli as similar and that these sweet stimuli are detected by multiple sweet receptors.
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Glutamate Taste: Discrimination between the Tastes of glutamate agonists and monosodium glutamate in rats.
Chemical senses, 2004Co-Authors: Eugene R. Delay, G. M. Sewczak, J. R. Stapleton, Stephen D. RoperAbstract:Taste aversion studies have demonstrated that rats conditioned to avoid monosodium glutamate (MSG) with amiloride added to reduce the intensity of the sodium component of MSG Taste, generalize this aversion to aspartic acid and to L-AP4, but not to ionotropic glutamate receptor agonists. That is, MSG, L-AP4 and aspartate have similar Tastes to rats. However, conditioned Taste aversion methods are unable to show to what extent the Tastes of two substances are different. If two substances activate the same afferent processes (e.g. Taste receptors), they are likely to produce the same Tastes, but if they activate different afferent processes, the subject may detect differences between the Tastes of the substances. In this study, rats were tested to determine if they could discriminate between the Tastes of these agonists and MSG. We also established the detection thresholds for NMDA, aspartic acid and L-AP4, with and without amiloride (a sodium channel antagonist). Taste threshold values were 1–4 mM for NMDA and aspartic acid and 0.5–2.5 µM for L-AP4. None were affected by 30 µM amiloride. Rats could readily distinguish between the Tastes of MSG and NMDA but they had difficulty discriminating between the Tastes of aspartic acid and MSG. Rats could also easily distinguish between 10–100 mM MSG and 0.01–5 mM L-AP4. However, in two separate experiments error rates increased significantly when L-AP4 concentrations were between 10–100 mM, indicating that the Tastes of L-AP4 and MSG were similar at these concentrations.
