Taste Aversion Learning Research Articles

Orexin-1 receptor antagonist in central nucleus of the amygdala attenuates the acquisition of flavor-taste preference in rats

Previous studies demonstrated that the intracerebroventricular administration of SB-334867-A, a selective antagonist of orexin OX1R receptors, blocks the acquisition of saccharin-induced conditioned flavor preference (CFP) but not LiCl-induced taste aversion learning (TAL). Orexinergic fibers from the lateral hypothalamus end in the central nucleus of the amygdala (CeA), which expresses orexin OX1R receptors. Taste and sensory inputs also are present in CeA, which may contribute to the development of taste learning. This study analyzed the effect of two doses (1.5 and 6μg/0.5μl) of SB-334867-A administered into the CeA on flavor–taste preference induced by saccharin and on TAL induced by a single administration of LiCl (0.15M, 20ml/kg, i.p.). Outcomes indicate that inactivation of orexinergic receptors in the CeA attenuates flavor–taste preference in a two-bottle test (saccharin vs. water). Intra-amygdalar SB-334867-A does not affect gustatory processing or the preference for the sweet taste of saccharin given that SB-334867-A- and DMSO-treated groups (control animals) increased the intake of the saccharin-associated flavor across training acquisition sessions. Furthermore, SB-334867-A in the CeA does not block TAL acquisition ruling out the possibility that functional inactivation of OX1R receptors interferes with taste processing. Orexin receptors in the CeA appear to intervene in the association of a flavor with orosensory stimuli, e.g., a sweet and pleasant taste, but could be unnecessary when the association is established with visceral stimuli, e.g., lithium chloride. These data suggest that orexinergic projections to the CeA may contribute to the reinforcing signals facilitating the acquisition of taste learning and the change in hedonic evaluation of the taste, which would have important implications for the OX1R-targeted pharmacological treatment of eating disorders.

Running-based pica in rats. Evidence for the gastrointestinal discomfort hypothesis of running-based taste aversion

Voluntary running in an activity wheel establishes aversion to paired taste in rats. A proposed mechanism underlying this taste aversion learning is gastrointestinal discomfort caused by running. We tested this hypothesis by measuring the pica behavior (kaolin clay intake) of rats, because it is known that rats engage in pica behavior after various nausea-inducing treatments including irradiation, motion sickness, and injection of emetic drugs such as lithium chloride (LiCl). Following a demonstration of the already-known phenomenon of LiCl-based pica in Experiment 1, we successfully showed running-based pica behavior in Experiment 2 where the running treatment was compared with a non-running control treatment (i.e., confinement in a locked wheel). These results suggest that not only LiCl but also running induces nausea in rats, supporting the gastrointestinal discomfort hypothesis of running-based taste aversion learning.

Sensory Cortical Population Dynamics Uniquely Track Behavior across Learning and Extinction

Neural responses in many cortical regions encode information relevant to behavior: information that necessarily changes as that behavior changes with learning. Although such responses are reasonably theorized to be related to behavior causation, the true nature of that relationship cannot be clarified by simple learning studies, which show primarily that responses change with experience. Neural activity that truly tracks behavior (as opposed to simply changing with experience) will not only change with learning but also change back when that learning is extinguished. Here, we directly probed for this pattern, recording the activity of ensembles of gustatory cortical single neurons as rats that normally consumed sucrose avidly were trained first to reject it (i.e., conditioned taste aversion learning) and then to enjoy it again (i.e., extinction), all within 49 h. Both learning and extinction altered cortical responses, consistent with the suggestion (based on indirect evidence) that extinction is a novel form of learning. But despite the fact that, as expected, postextinction single-neuron responses did not resemble "naive responses," ensemble response dynamics changed with learning and reverted with extinction: both the speed of stimulus processing and the relationships among ensemble responses to the different stimuli tracked behavioral relevance. These data suggest that population coding is linked to behavior with a fidelity that single-neuron coding is not.

High-resolution lesion-mapping strategy links a hot spot in rat insular cortex with impaired expression of taste aversion learning

Gustatory cortex (GC), an assemblage of taste-responsive neurons in insular cortex, is widely regarded as integral to conditioned taste aversion (CTA) retention, a link that has been primarily established using lesion approaches in rats. In contrast to this prevailing view, we found that even the most complete bilateral damage to GC produced by ibotenic acid was insufficient to disrupt postsurgical expression of a presurgical CTA; nor were such lesions sufficient to disrupt postsurgical acquisition and initial expression of a second CTA. However, some rats with lesions were significantly impaired on these tests. Further examination of all conditioned rats with lesions, regardless of the lesion topography, revealed a significant positive association between damage in the posterior portion of GC and especially within adjacent posterior regions of insular cortex. Accordingly, we developed a high-resolution lesion-mapping program that permitted the overlay of the individual lesion maps from rats with CTA impairments to produce a groupwise aggregate lesion map. Comparison of this map with one derived from the unimpaired counterparts indicated a specific lesion "hot spot" associated with CTA deficits that included the most posterior end of GC and overlying granular layer and encompassed an area provisionally referred to in the literature as visceral cortex. Thus, the detailed mapping of the lesion in behaviorally defined subgroups of rats allowed us to exploit the variability in performance to uncloak an important potential component of the functional topography of insular cortex; such an approach could have general applicability to other brain structure-function endeavors as well.

Running-based taste aversion learning in five strains of rats

Although it is well known that voluntary wheel running works as an effective unconditioned stimulus to cause conditioned taste aversion (CTA) in several strains of rats, there is no study that explores strain differences in running-based CTA. The present study examines this issue with regard to five frequently used rat strains. Experiment 1 compared Sprague–Dawley versus Wistar rats from two suppliers, with the target taste being salty (NaCl+MSG) and then sweet (saccharin). Experiments 2, 3, and 4 tested rats of Wistar versus Long-Evans, Lewis versus Fischer, and Sprague–Dawley versus Lewis strains, respectively, with sweet and then salty solutions. None of the experiments showed any reliable strain differences in the strength of running-based CTA, suggesting the robustness of this learning phenomenon.

Excitotoxic lesion of the hippocampus of Wistar rats disrupts the circadian control of the latent inhibition of taste aversion learning

Previous experiments have shown that changes in the time of day between taste pre-exposure and conditioning prevent the latent inhibition of conditioning taste aversion. The effect of these changes in circadian context between pre-exposure and conditioning on the magnitude of the learned aversion appears to be similar to the effect of changes in spatial context on this type of learning. To elucidate the brain areas involved in this circadian dependence of latent inhibition of conditioning taste aversion, the effect of excitotoxic lesions of the hippocampus, a region related to spatial-contextual modulation in this learning process, was analyzed. The latent inhibition of conditioning taste aversion in animals with hippocampal lesions, that were pre-exposed and conditioned to the same or different time of day, was compared with the response of animals exposed to either conditions (“same” or “different”) but had undergone amygdala lesions or sham lesions. The results showed that selective dorsal hippocampus lesion eliminated the circadian dependence of latent inhibition of taste aversion. A change in the time of day between pre-exposure and conditioning did not prevent latent inhibition in animals with hippocampal lesions. In contrast, this change prevented latent inhibition in the amygdala-lesioned and sham groups. These findings suggest that the hippocampus contains a selective mechanism that modulates the contextual dependency of the latent inhibition of conditioning taste aversion without interfering with the effect of taste pre-exposure itself. This study may help to understand the possible common involvement of the hippocampus in different types of contextual control of associative learning.

A history of morphine-induced taste aversion learning fails to affect morphine-induced place preference conditioning in rats

Drugs of abuse have both rewarding and aversive effects, as indexed by the fact that they support place preferences and taste aversions, respectively. In the present study, we explored whether having a history with the aversive effects of morphine (via taste aversion conditioning) impacted the subsequent rewarding effects of morphine, as measured in the place preference design. In Experiment 1, rats were exposed to a taste aversion procedure in which saccharin was followed by morphine. Place preference conditioning was then initiated in which animals were injected with morphine and placed on one side of a two-chambered apparatus. Animals with a taste aversion history acquired place preferences to the same degree as controls without such a history, suggesting that morphine's affective properties condition multiple effects, dependent on the specific stimuli present during conditioning. To determine whether these results were a reflection of processes operating in traditional associative conditioning, in a modified blocking procedure, place preference conditioning was attempted in the presence of a taste previously associated with morphine (Exp. 2). Under these conditions, animals still acquired morphine-induced place preferences comparable to those of animals without a morphine or conditioning history. These results are consistent with the position that drugs of abuse have multiple stimulus effects (positive and negative) that are differentially associated with specific stimuli (environmental and taste) that drive different behavioral responses (approach and avoidance).

Effects of group II and III metabotropic glutamate receptor ligands on conditioned taste aversion learning

Metabotropic glutamate (mGlu) receptors impact learning and memory. Although some evidence indicates the importance of these receptors in conditioned taste aversion (CTA), the subtype-specific involvement of mGlu receptors in this associative learning task remains to be determined. These experiments examined the effects of (1R,4R,5S,6R)-4-amino-2-oxabicyclo[3.1.0]hexane-4,6-dicarboxylic acid (LY379268), a selective group II mGlu receptor agonist, cis-2-[[(3,5-dichlorophenyl)amino]carbonyl]cyclohexanecarboxylic acid (VU0155041), a mGlu4 positive allosteric modulator, N,N′-dibenzhydrylethane-1,2-diamine (AMN082), a mGlu7 allosteric agonist, and 6-(4-methoxyphenyl)-5-methyl-3-(4-pyridinyl)-isoxazolo[4,5-c]pyridin-4(5H)-one (MMPIP), a mGlu7 negative allosteric modulator, on the acquisition of CTA using male Sprague-Dawley rats. Systemic injections of LY379268, AMN082, and MMPIP prior to conditioning decreased the acquisition of CTA, revealing that mGlu2/3 and mGlu7 are involved in CTA learning.

Nonreinforced flavor exposure attenuates the effects of conditioned taste aversion on both flavor consumption and cue palatability

Nonreinforced exposure to a cue tends to attenuate subsequent conditioning with that cue-an effect referred to as latent inhibition (LI). In the two experiments reported here, we examined LI effects in the context of conditioned taste aversion by examining both the amount of consumption and the microstructure of the consummatory behavior (in terms of the mean size of lick clusters). The latter measure can be taken to reflect affective responses to, or the palatability of, the solution being consumed. In both experiments, exposure to a to-be-conditioned flavor prior to pairing the flavor with nausea produced by lithium chloride attenuated both the reduction in consumption and the reduction in lick cluster sizes typically produced by taste aversion learning. In addition, we observed a tendency (especially in the lick cluster measure) for nonreinforced exposure to reduce neophobic responses to the test flavors. Taken together, these results reinforce the suggestion from previous experiments using taste reactivity methods that LI attenuates the effects of taste aversion on both consumption and cue palatability. The present results also support the suggestion that the failure in previous studies to see concurrent LI effects on consumption and palatability was due to a context specificity produced by the oral taste infusion methods required for taste reactivity analyses. Finally, the fact that the pattern of extinction of conditioned changes in consumption and in lick cluster sizes was not affected by preexposure to the cue flavors suggests that LI influenced the quantity but not the quality of conditioned taste aversion.

Gene Network Analysis in Amygdala following Taste Aversion Learning in Rats.

Conditioned taste aversion (CTA) is an adaptive behavior that benefits survival of animals including humans and also serves as a powerful model to study the neural mechanisms of learning. Memory formation is a necessary component of CTA learning and involves neural processing and regulation of gene expression in the amygdala. Many studies have been focused on the identification of intracellular signaling cascades involved in CTA, but not late responsive genes underlying the long-lasting behavioral plasticity. In this study, we explored in silico experiments to identify persistent changes in gene expression associated with CTA in rats. We used oligonucleotide microarrays to identify 248 genes in the amygdala regulated by CTA. Pathway Studio and IPA software analyses showed that the differentially expressed genes in the amygdala fall in diverse functional categories such as behavior, psychological disorders, nervous system development and function, and cell-to-cell signaling. Conditioned taste aversion is a complex behavioral trait which involves association of visceral and taste inputs, consolidation of taste and visceral information, memory formation, retrieval of stored information, and extinction phase. In silico analysis of differentially expressed genes is therefore necessary to manipulate specific phase/stage of CTA to understand the molecular insight.

PKM-ζ is not required for hippocampal synaptic plasticity, learning and memory.

Long-term potentiation (LTP), a well-characterized form of synaptic plasticity, has long been postulated as a cellular correlate of learning and memory. Although LTP can persist for long periods of time, the mechanisms underlying LTP maintenance, in the midst of ongoing protein turnover and synaptic activity, remain elusive. Sustained activation of the brain-specific protein kinase C (PKC) isoform protein kinase M-ζ (PKM-ζ) has been reported to be necessary for both LTP maintenance and long-term memory. Inhibiting PKM-ζ activity using a synthetic zeta inhibitory peptide (ZIP) based on the PKC-ζ pseudosubstrate sequence reverses established LTP in vitro and in vivo. More notably, infusion of ZIP eliminates memories for a growing list of experience-dependent behaviours, including active place avoidance, conditioned taste aversion, fear conditioning and spatial learning. However, most of the evidence supporting a role for PKM-ζ in LTP and memory relies heavily on pharmacological inhibition of PKM-ζ by ZIP. To further investigate the involvement of PKM-ζ in the maintenance of LTP and memory, we generated transgenic mice lacking PKC-ζ and PKM-ζ. We find that both conventional and conditional PKC-ζ/PKM-ζ knockout mice show normal synaptic transmission and LTP at Schaffer collateral-CA1 synapses, and have no deficits in several hippocampal-dependent learning and memory tasks. Notably, ZIP still reverses LTP in PKC-ζ/PKM-ζ knockout mice, indicating that the effects of ZIP are independent of PKM-ζ.

Involvement of Insulin-Like Peptide in Long-Term Synaptic Plasticity and Long-Term Memory of the Pond SnailLymnaea stagnalis

The pond snail Lymnaea stagnalis is capable of learning taste aversion and consolidating this learning into long-term memory (LTM) that is called conditioned taste aversion (CTA). Previous studies showed that some molluscan insulin-related peptides (MIPs) were upregulated in snails exhibiting CTA. We thus hypothesized that MIPs play an important role in neurons underlying the CTA-LTM consolidation process. To examine this hypothesis, we first observed the distribution of MIP II, a major peptide of MIPs, and MIP receptor and determined the amounts of their mRNAs in the CNS. MIP II was only observed in the light green cells in the cerebral ganglia, but the MIP receptor was distributed throughout the entire CNS, including the buccal ganglia. Next, when we applied exogenous mammalian insulin, secretions from MIP-containing cells or partially purified MIPs, to the isolated CNS, we observed a long-term change in synaptic efficacy (i.e., enhancement) of the synaptic connection between the cerebral giant cell (a key interneuron for CTA) and the B1 motor neuron (a buccal motor neuron). This synaptic enhancement was blocked by application of an insulin receptor antibody to the isolated CNS. Finally, injection of the insulin receptor antibody into the snail before CTA training, while not blocking the acquisition of taste aversion learning, blocked the memory consolidation process; thus, LTM was not observed. These data suggest that MIPs trigger changes in synaptic connectivity that may be correlated with the consolidation of taste aversion learning into CTA-LTM in the Lymnaea CNS.

Odor-mediated taste learning requires dorsal hippocampus, but not basolateral amygdala activity

Mediated learning is a unique cognitive phenomenon in which mental representations of physically absent stimuli enter into associations with directly-activated representations of physically present stimuli. Three experiments investigated the functional physiology of mediated learning involving the use of odor–taste associations. In Experiments 1a and 1b, basolateral amygdala lesions failed to attenuate mediated taste aversion learning. In Experiment 2, dorsal hippocampus inactivation impaired mediated learning, but left direct learning intact. Considered with past studies, the results implicate the dorsal hippocampus in mediated learning generally, and suggest a limit on the importance of the basolateral amygdala.

Assessment of dopaminergic involvement in cocaine‐induced conditioned taste aversions

Although cocaine induces conditioned taste aversions (CTA), little is known about the mechanisms underlying this effect. It has been suggested that cocaine's actions as a nonselective monoamine transport inhibitor may be mediating this suppression. Given the role of dopamine (DA) in cocaine reward, this neurotransmitter system is of particular interest. The present experiments used direct pharmacological antagonism (with the DA antagonist haloperidol) to determine a role, if any, of DA in the induction of CTAs by cocaine. Following the determination of behaviorally active doses of haloperidol with no aversive effects on their own (Experiment 1), animals were given 1 mg/kg haloperidol prior to various doses of cocaine in a taste aversion procedure (Experiment 2). Under these conditions, haloperidol blocked cocaine‐induced CTAs (at the 18 and 32 mg/kg doses). These results suggest that DA has a role in cocaine‐induced CTAs. These data are discussed in the context of previous work demonstrating roles for both norepinephrine and serotonin in cocaine‐induced taste aversion learning as well as current research investigating DA transporter inhibitors and cocaine within the cross‐drug preexposure preparation.

Odor-avoidance or odor-preference induced by amphetamine in the infant rat depending on the dose and testing modality

By the second postnatal week of life infant rats can acquire taste avoidance induced by amphetamine. Psychostimulant drugs supports appetitive and aversive learning in adult rats. Their appetitive effects are more likely to become associated with contextual cues, while the aversive ones have been consistently found in taste aversion learning. To explain this paradox, it has been proposed that rats would avoid a taste that predicts a change in their homeostasis because this species cannot vomit. In this study we assessed the motivational properties of amphetamine in preweanling rats by means of an odor conditioning preparation, which enables the analysis of the hedonic value of the memory by means of a consumption test or in terms of locomotor approach to the odor. Results indicate that regardless of the amphetamine dose (1 or 5mg/kg), when animals were evaluated in the intake test, subjects avoided the odor. However, the outcome in the locomotor avoidance test varied as a function of the amphetamine dose. Rats trained with the low dose (1mg/kg) showed odor preference, while the highest amphetamine dose (5mg/kg) induced odor avoidance. When LiCl was employed as an unconditioned stimulus (US), rats showed avoidance in the intake and locomotor activity tests. These data indicate that amphetamine, like other drugs of abuse, supports appetitive conditioning in preweanling rats. Interestingly, infant rats expressed conditioned odor avoidance or preference depending on the dose and testing modality. Results were discussed considering current theories of avoidance learning induced by rewarding drugs.

Effects of an activity-based anorexia procedure on within-session changes in nose-poke responding

This study tested the effects of an activity-based anorexia (ABA) procedure on within-session changes in responding. In the ABA group (N=8), rats were given a 60-min feeding session and allowed to run in a running wheel for the remainder of each day. During the daily 60-min feeding session, each nose-poke response was reinforced by a food pellet. In the control group (N=8), rats experienced the same procedure except that the wheel was locked and thus rats could not run. The experiment lasted for 6 days. Rats in the ABA group consumed less and lost more body weight than those in the control group. Within-session decreases in nose-poke responding were steeper for ABA than control rats. In addition, response rates were well described as linear functions of the cumulative number of reinforcers in both groups (r2s>.96). The regression lines for the ABA group had steeper slopes and smaller x-axis intercepts than those for the control group. However, the y-axis intercepts of the regression lines were similar for the two groups. These effects were different from the effects of taste-aversion learning induced by post-session wheel running (Aoyama, 2007), suggesting a different mechanism in each preparation.

Impaired associative taste learning and abnormal brain activation in kinase-defective eEF2K mice

Memory consolidation is defined temporally based on pharmacological interventions such as inhibitors of mRNA translation (molecular consolidation) or post-acquisition deactivation of specific brain regions (systems level consolidation). However, the relationship between molecular and systems consolidation are poorly understood. Molecular consolidation mechanisms involved in translation initiation and elongation have previously been studied in the cortex using taste-learning paradigms. For example, the levels of phosphorylation of eukaryotic elongation factor 2 (eEF2) were found to be correlated with taste learning in the gustatory cortex (GC), minutes following learning. In order to isolate the role of the eEF2 phosphorylation state at Thr-56 in both molecular and system consolidation, we analyzed cortical-dependent taste learning in eEF2K (the only known kinase for eEF2) ki mice, which exhibit reduced levels of eEF2 phosphorylation but normal levels of eEF2 and eEF2K. These mice exhibit clear attenuation of cortical-dependent associative, but not of incidental, taste learning. In order to gain a better understanding of the underlying mechanisms, we compared brain activity as measured by MEMRI (manganese-enhanced magnetic resonance imaging) between eEF2K ki mice and WT mice during conditioned taste aversion (CTA) learning and observed clear differences between the two but saw no differences under basal conditions. Our results demonstrate that adequate levels of phosphorylation of eEF2 are essential for cortical-dependent associative learning and suggest that malfunction of memory processing at the systems level underlies this associative memory impairment.

The unconditioned stimulus pre‐exposure effect in preweanling rats in taste aversion learning: Role of the training context and injection cues

The unconditioned stimulus pre-exposure effect (US-PE) refers to the interference paradigm in which acquisition of the conditioned response is retarded due to prior experience with the US. Most studies analyzing the psychological mechanisms underlying this effect have been conducted with adult rats. The most widely accepted hypothesis explains this effect as a contextual blocking effect. Contextual cues associated with the US block the conditioned stimulus (CS)-US association during conditioning. The modulatory role of a context devoid of distinctive olfactory attributes is not observable until approximately PD23 in rats, including modulation of interference paradigms such as latent inhibition or extinction. In this study, we analyzed US-PE in preweanling rats along with the role of the training context in this effect in terms of conditioned taste aversion preparation. Pre-exposure to LiCl before conditioning retarded the acquisition of taste aversion. The US-PE was observed in preweanling rats when, during pre-exposure, subjects were exposed to the conditioning context, and this effect was not attenuated either by the administration of the US in a familiar environment (Experiment 1a), or by the presence of an alternative, more salient context during pre-exposure (Experiment 1b). Additionally, the US-PE was still observed when the route by which the US was administered was changed between the pre-exposure and conditioning phases (Experiment 2a) as well as when the injection cues were removed during conditioning (Experiment 2b). These experiments show a strong US-PE in preweanling rats and fail to support the contextual blocking hypothesis, at least in this stage of ontogeny.

Serial overshadowing of taste aversion learning by stimuli preceding the target taste

Three experiments tested whether events taking place before a rat has access to a target taste, sucrose, can proactively interfere with the acquisition of a sucrose aversion when sucrose is followed by a lithium chloride injection. Using a serial overshadowing procedure with various delays before lithium injection, proactive interference by a taste (Experiments 1 and 3) and by a novel context (Experiment 2) was found following two conditioning sessions, but not after a single conditioning session. Conversely, overshadowing by a taste given after the target was detectable after a single conditioning trial (Experiment 3) and, thus, indicated that retroactive interference involves a process different from that producing proactive interference. A simulation confirmed that the results are consistent with a modified Rescorla and Wagner (1972) interpretation of Revusky's (1971) concurrent interference theory of delay learning.

Relationship between learning ability and starvation status in taste aversion learning of a pond snail

Event Abstract Back to Event Relationship between learning ability and starvation status in taste aversion learning of a pond snail Etsuro Ito1*, Koichi Mita1, Dai Hatakeyama1, Ryuichi Okada1, Mika Morikawa1, Yuki Sakamoto1, Miki Yamagishi1 and Akiko Okuta2 1 Tokushima Bunri University, Kagawa School of Pharmaceutical Science, Japan 2 Kyoto University, Graduate School of Science, Japan The pond snail Lymnaea stagnalis acquires taste aversion learning and maintains it as a long-term memory (LTM) referred to as conditioned taste aversion. In the present study, we examined the relationship among learning ability, starvation period and hemolymph glucose concentration in taste aversion learning. One-day mild starvation improves the learning score and keeps good LTM, but 5-day heavy starvation failed the snails to learn the taste aversion. During this 5-day starvation period, the hemolymph glucose concentration appeared to decrease. On the other hand, when we injected glucose into the abdominal cavity or fed sucrose to 1-day mild starved snails for a short period, the snails showed worse scores than the case of no injection or ingestion. Further, when mammalian insulin was injected into snails with a complete bellyful of food, the hemolymph glucose concentration decreased and the learning score and LTM were improved. The number of insulin-like receptors in the Lymnaea brain was not changed by taste aversion learning. These results showed that learning ability depends on the starvation period and the hemolymph glucose concentration and that learning ability can be controlled by direct manipulation of hemolymph glucose concentration or injection of insulin in taste aversion learning of Lymnaea. Keywords: Lymnaea, conditioned taste aversion, Glucose, Insulin, Starvation Conference: Tenth International Congress of Neuroethology, College Park. Maryland USA, United States, 5 Aug - 10 Aug, 2012. Presentation Type: Poster (but consider for Participant Symposium) Topic: Learning, Memory and Behavioral Plasticity Citation: Ito E, Mita K, Hatakeyama D, Okada R, Morikawa M, Sakamoto Y, Yamagishi M and Okuta A (2012). Relationship between learning ability and starvation status in taste aversion learning of a pond snail. Conference Abstract: Tenth International Congress of Neuroethology. doi: 10.3389/conf.fnbeh.2012.27.00088 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 18 Apr 2012; Published Online: 07 Jul 2012. * Correspondence: Prof. Etsuro Ito, Tokushima Bunri University, Kagawa School of Pharmaceutical Science, Sanuki, 769-2193, Japan, eito@waseda.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Etsuro Ito Koichi Mita Dai Hatakeyama Ryuichi Okada Mika Morikawa Yuki Sakamoto Miki Yamagishi Akiko Okuta Google Etsuro Ito Koichi Mita Dai Hatakeyama Ryuichi Okada Mika Morikawa Yuki Sakamoto Miki Yamagishi Akiko Okuta Google Scholar Etsuro Ito Koichi Mita Dai Hatakeyama Ryuichi Okada Mika Morikawa Yuki Sakamoto Miki Yamagishi Akiko Okuta PubMed Etsuro Ito Koichi Mita Dai Hatakeyama Ryuichi Okada Mika Morikawa Yuki Sakamoto Miki Yamagishi Akiko Okuta Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.