Biomedical subjects

S W Kiefer

Publications and source records attributed to S W Kiefer.

18 recordsLinked to original sources

PubMed1992

Taste avoidance, but not aversion, learning in rats lacking gustatory cortex.

Control rats rapidly learned to avoid drinking either a sucrose solution (Experiment 1) or a NaCl solution (Experiment 2) when the taste was paired with illness. These rats also produced aversive reactivity to each of these solutions in a taste reactivity test. Rats that lacked gustatory cortex (GC) learned to avoid drinking sucrose and NaCl, albeit at a slower rate than control rats. GC rats failed to display aversive reactivity to these tastes. The GC rats did show normal aversive reactivity to a strong quinine HCl solution during additional tests. It is suggested that the avoidance developed by GC rats did not entail a palatability shift of the conditional stimulus as it did in control rats. This altered learning strategy may account for the consistent learning deficits found in GC rats trained to avoid tastes.

Animals↗

PubMed1991

Odor cue mediation of alcohol aversion learning in rats lacking gustatory neocortex.

Normal rats presented with a 5% alcohol solution followed by lithium chloride-induced illness quickly learned to avoid drinking alcohol. After training, the rats also avoided drinking water in the presence of the alcohol odor alone, whether tested immediately or 1 month later. In Experiment 1, rats with gustatory neocortex (GN) ablations also developed strong alcohol aversions when the alcohol solution was paired with illness. They also showed normal avoidance of drinking in the presence of the alcohol odor alone when tested soon after training. In Experiment 2, when normal rats were trained to avoid alcohol, given GN ablations, and then tested for retention 1 month later, avoidance of drinking water in the presence of the odor alone was significant but attenuated somewhat in relation to trained control rats. These data support the hypothesis that rats lacking GN partially acquire alcohol aversions by using odor cues and confirm that associative learning is intact in these rats despite the fact that GN rats display significant deficits in aversion learning when only tastes are paired with illness.

Alcohol Drinking↗

PubMed1990

Taste reactivity in alcohol preferring and nonpreferring rats.

Taste reactivity tests were used to examine the orofacial responses of alcohol preferring (P) rats and alcohol nonpreferring (NP) rats to the taste of alcohol. In the initial exposure, naive rats were tested for reactivity to five concentrations of alcohol (5%, 10%, 20%, 30%, and 40% v/v), water, and one solution each of sucrose and quinine. A two-bottle consumption test was then given for a 3-week period to allow the rats access to 10% alcohol. After the preference test, a second taste reactivity test was done using the same solutions as in the initial reactivity test. The results indicated no significant differences in taste reactivity between P rats and NP rats on the initial exposure, except that NP rats made significantly more mouth movements. During the two-bottle tests, consumption of alcohol by P rats was consistently higher than that of NP rats across all test days. On the second taste reactivity test, P rats showed an increase in the number of ingestive responses and a decrease in the number of aversive responses to alcohol. NP rats' taste reactivity to alcohol remained unchanged from Exposure 1 to Exposure 2. P rats' and NP rats' responses to sucrose and quinine did not change from Exposure 1 to Exposure 2. It was concluded that there were no innate taste response differences between P and NP rats to alcohol but that following alcohol experience, P rats showed a significant increase in ingestive responses and a concomitant decrease in aversive responses to the taste of alcohol.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗

PubMed1989

Taste reactivity to alcohol in rats.

Rats were infused intraorally with 4 concentrations of ethanol (3%, 6%, 9%, and 12%), and their subsequent oral, facial, and bodily responses were videotaped and analyzed. Naive rats did not display significant changes in ingestive-type responding over the concentrations tested. A significant increase in aversive responses was noted, with the largest number of aversive responses found with the 12% solution. Initial reactivity failed to predict subsequent consumption when rats were given free access to the same alcohol concentrations during 2-bottle tests. Reactivity testing after the period of alcohol access indicated that only the aversive responding changed significantly from the initial reactivity, with rats showing fewer aversive responses. The results indicated how the taste of alcohol is perceived by naive rats and how this perception is changed after consummatory experience with alcohol.

Alcohol Drinking↗

PubMed1988

Alcohol aversion generalization in rats: specific disruption of taste and odor cues with gustatory neocortex or olfactory bulb ablations.

Rats with ablations of the gustatory neocortex (Experiment 1) and rats with olfactory bulb ablations (Experiment 2) were compared with normal rats for aversion generalization to both single taste solutions (sucrose, sodium chloride, quinine hydrochloride, hydrochloric acid) and compound taste solutions (pairs of the four single tastants) following alcohol aversion training. All rats acquired equal and strong alcohol aversions. Control rats showed consistent aversion generalization to both the sucrose + quinine and the sucrose + hydrochloric acid solutions; no significant generalization occurred to the single tastants except a weak generalization to sucrose in Experiment 2. Rats with gustatory neocortical ablations failed to show aversion generalization to any of the taste solutions. Rats with olfactory bulbectomies displayed the same aversion generalization functions as control rats but exhibited significantly faster extinction of the alcohol aversion than did the trained control rats. Results from the present experiments suggest that during alcohol aversion learning, rats lacking gustatory neocortex use odor cues (no taste generalization), whereas rats lacking olfactory bulbs utilize taste cues (normal taste generalization).

Afferent Pathways↗

PubMed1987

Cessation of male rat copulatory behavior using illness as punishment: facilitation with a novel odor.

Two experiments were conducted to examine learned copulatory avoidance in male rats. One group of males was presented with receptive females that had been sprayed with a 2% almond solution, and the other group was presented with nonalmond odorous, receptive females. Following each test, males were made ill with lithium chloride (LiCl) by intragastric intubation or intraperitoneal injection. Results showed that male rats presented with almond-odorous females developed significant avoidance of copulatory behavior. Conditioning in males exposed to receptive females without the almond odor developed little, if any, avoidance. In Experiment 2, it was found that route of LiCl administration was not a factor in the results.

Animals↗

PubMed1986

Flavor-illness aversions: the role of the amygdala in the acquisition of taste-potentiated odor aversions.

In the present experiments the role of the amygdaloid complex and its specific nuclei were tested in the conditioning of taste potentiated odor aversions. In the first experiment two groups of rats were given either large electrolytic lesions in the amygdala (AMX) or sham operations (SH). Postoperatively, these rats were trained to avoid either a taste, an odor, or a taste-odor compound using LiCl illness. Subsequent tests with odor and taste alone showed that the SH group developed strong taste and odor aversions; however, the AMX group failed to display either an odor or taste aversion. In the second experiment, another four groups of rats received either lesions in the medial and basomedial nuclei (M), central nuclei (C), lateral and basolateral (L), or sham operations (SH). The results from postoperative conditioning showed that all groups had strong taste and odor aversions, except group L which displayed a significant disruption of odor aversion learning. In conclusion, these data indicate that the amygdala is involved in the acquisition of taste, odor and potentiated odor aversions learning. Moreover, it is demonstrated that the lateral and/or basolateral nuclei are particularly involved in the development of potentiated odor aversions learning.

Amygdala↗

PubMed1985

Ingestive responses to homeostatic challenges in rats with ablations of the anterolateral neocortex.

Because rats with either anterolateral neocortical or lateral hypothalamic (LH) damage initially display similar feeding and drinking deficits and recovery patterns, the possibility that anterolateral neocortical ablations would also produce similar chronic ingestive impairments to glucoprivic and hydrational challenges was examined. In general, rats with anterolateral neocortical ablations exhibited normal feeding responses to food deprivation and glucoprivation induced by insulin or moderate doses of 2-deoxy-D-glucose (2-DG), but their response to a high dose (500 mg/kg) of 2-DG was impaired. These animals also drank normally in response to hypertonic saline injections and following water deprivation, but only if food was available during the test session, results indicating that they drank prandially. Results indicate that although the anterolateral neocortex and LH are anatomically related, these brain regions appear to be functionally dissimilar in terms of the regulation of ingestion.

Animals↗

PubMed1985

Neural mediation of conditioned food aversions.

The above discussion is only a brief review of what is known about the neural mediation of conditioned food aversions. Although several other approaches were not mentioned (e.g. biochemical studies), one can still appreciate the value of the aversion paradigm for providing important information about neural mechanisms in learning and memory. A theoretical approach that may be valuable in understanding brain function in conditioned food aversion data is Hughlings Jackson's hierarchical notions of nervous organization. Hedonic responses to food stimuli appear to be brainstem reflexes. On top of these are rostral brain structures that add greater complexity to the consummatory behavior of the organism. An important aspect of this complexity is reflected in an animal's ability to form conditioned food aversions, a process undoubtedly tied intimately to particular neural mechanisms.

Afferent Pathways↗

PubMed1982

Flavor-illness aversions: gustatory neocortex ablations disrupt taste but not taste-potentiated odor cues.

Two experiments evaluated the contribution of the gustatory neocortex (GN) to the potentiation of odor by taste during illness-induced aversions in rats. In Experiment 1, rats lacking GN and control rats were given an odor, a taste, or an odor-taste compound cue followed by intragastric gavage of lithium chloride. Prior to conditioning, neophobia for flavored solutions was absent in rats with GN lesions. After pairing with LiCl, GN rats developed normal conditioned odor aversions (Experiment 1B), whereas conditioned taste aversions were attenuated (Experiment 1A) or totally blocked (Experiment 1B). Potentiation of odor by taste after compound conditioning was evident in both control and GN rats, although GN lesions attenuated the effect slightly in Experiment 1B. In Experiment 2, normal rats were given compound conditioning to induce potentiated odor aversions and then given GN lesions prior to tests with the odor and taste components. Taste aversion retention was disrupted totally by GN ablation; potentiated odor aversions were retained by both groups, although the GN group extinguished faster. Gustatory neocortex ablations produced differential effects on odor and taste, disrupting taste memorial and associative processes but leaving odor conditioning and the potentiation of odor by taste processes relatively unaffected. Integrity of the GN apparently is not necessary for the acquisition or retention of potentiation odor aversions.

Animals↗

PubMed1977

Absence of differential associative responses to novel and familiar taste stimuli in rats lacking gustatory neocortex.

Rats lacking gustatory neocortex (n = 24) and normal rats (n = 24) were familiarized to either hydrochloric acid (10(-1.6) M) or quinine hydrochloride (10(-4) M) solutions during free-drinking trials. They were trained subsequently to avoid either the familiar or the novel taste stimulus, using a balanced design, by pairing the to-be-associated taste with ip injections of apomorphine hydrochloride. Balanced, nonpaired presentations of the other taste solution and water were presented also. Normal rats more efficiently learned to avoid the novel compared with the familiar taste. Rats with gustatory neocortex lesions did not differentiate novel from familiar tastes. They learned aversions to both in a manner highly similar to the aversion learning of familiar tastes by the normal group. Therefore, rats lacking gustatory neocortex displayed an associative deficiency, relative to normal, only when they were trained on novel stimuli. This observation supports an earlier suggestion that gustatory neocortex lesions disrupt the conditionability of taste stimuli by reducing or eliminating responses to taste novelty. This suggestion is supported further by the absence of a "neophobic" response in the operated rats to the first presentation of a taste stimulus.

Animals↗

PubMed1974

Target structure and echo spectral discrimination by echolocating bats.

Echolocating bats can use sonar to discriminate among targets which reflect echoes differing in spectral distribution of energy but not in overall intensity. They can detect differences smaller than 1 millimeter in fine target structure. Bats may be capable of classifying targets from echo spectral signatures and might thus be able to distinguish among flying insect prey by sonar.

Animals↗

PubMedDate not supplied

Neocortical involvement in the acquisition and retention of learned alcohol aversions in rats.

In one experiment, rats lacking gustatory neocortex (GN) were compared with control (both normal and control lesion) rats in the acquisition of a learned alcohol aversion. In a second experiment, the effect of GN ablations on preoperatively learned alcohol aversions was examined. Results showed that rats lacking GN both learned and retained alcohol aversions in a normal manner. These same GN rats, however, extinguished the alcohol aversions significantly faster than controls. These results are in contrast to previous data which indicated that the integrity of the GN was necessary for normal acquisition and retention of learned taste aversions. It is suggested that the odor qualities present in the alcohol stimulus account for the relatively normal performance of GN rats.

Alcohol Drinking↗

PubMedDate not supplied

Learned alcohol aversions in rats: gustatory and olfactory components.

The gustatory and olfactory basis of learned alcohol aversions was examined by testing rats with either gustatory neocortex ablations, olfactory bulb ablations, or a combination of both ablations. In the first experiment operated rats were compared with control rats in the acquisition of a learned alcohol aversion. In the second experiment, the effect of ablations on preoperatively-learned alcohol aversions was examined. Rats lacking gustatory neocortex learned and retained alcohol aversions normally although these rats extinguished the aversions faster than normal rats. Olfactory bulb ablation alone failed to disrupt normal aversion learning but completely eliminated retention of a previously acquired aversion. Combination ablations produced severe deficits both in acquisition and retention of learned alcohol aversions. The results indicate that, besides having gustatory qualities, the odor quality of alcohol is important in determining the associative and memorial characteristics of alcohol.

Animals↗

PubMedDate not supplied

Neural and behavioral responsivity to ethyl alcohol as a tastant.

Three experiments were designed to study the sensory properties of ethyl alcohol (EtOH) in the rat. In Experiment 1, a conditioned taste aversion (CTA) was produced to 3%, 6% or 9% EtOH. None of these aversions generalized to any of the 4 basic tastants. However, rats in the 6% and 9% EtOH groups did generalize the CTA to a mixture of sucrose-QHCl but not to a mixture of NaCl-HCl. In Experiment 2, a CTA was produced to 6% EtOH and animals were then tested with all 6 combinations of the basic tastants. The CTA was found to generalize significantly to sucrose-QHCl and marginally to sucrose-HCl. In Experiment 3, single unit responses to gustatory stimuli were recorded in the nucleus of the tractus solitarius. Solutions of NaCl, HCl, sucrose, QHCl, 6% and 9% EtOH were bathed over the rostral tongue through a plastic flow chamber. Approximately half of the units responded to 9% EtOH. Analysis of the across-unit patterns of response revealed a weak relationship between responses to EtOh and sucrose in the first 1.0 sec of response.

Animals↗

PubMedDate not supplied

Alcohol preference in rats lacking gustatory neocortex.

Ingestion of alcohol solutions (in concentrations from 0.5 to 12% v/v) was examined in three experiments where rats lacking gustatory neocortex (GN) were compared with intact and control lesion rats. Two experiments tested alcohol consumption during a restricted schedule of fluid access with one or two bottle tests. The last experiment involved testing with continuous access to water and alcohol solutions in two bottle tests. Subgroups of rats in each experiment were presented with either an ascending or descending order of concentrations. In all experiments, GN rats consumed less total fluid during testing (relative to control rats). In general, GN rats exhibited similar patterns of alcohol consumption as that found in control rats. Where differences between GN rats and control rats were found, GN rats consumed more alcohol than control rats during tests with restricted fluid access. During continuous fluid access, however, no significant differences between GN rats and control rats were found.

Alcohol Drinking↗

PubMedDate not supplied

Similarity of taste reactivity responses to alcohol and sucrose mixtures in rats.

The orofacial responses of rats following infusion of taste solutions were examined in two experiments. In the first experiment, naive rats were presented with a 6% alcohol solution and three sucrose mixtures (sucrose combined with quinine hydrochloride, hydrochloric acid, and sodium chloride, respectively) on separate trials and the resulting taste reactivity was examined. The only difference among the solutions was that alcohol elicited a significantly larger number of aversive responses (e.g., gapes, passive drips) than the sucrose mixtures. In the second experiment, naive rats were trained to avoid 6% alcohol using standard conditioned aversion procedures; rats were then tested for reactivity to the three sucrose mixtures and the alcohol solution. With the alcohol solution, trained rats displayed significantly fewer ingestive responses and significantly more aversive responses than control rats. The response of trained rats to the sucrose + quinine solution was similar to that of alcohol: fewer ingestive responses and more aversive responses than control rats. The number of aversive responses to the alcohol and the sucrose + quinine mixture by the trained rats did not differ significantly. Reactivity to the sucrose + hydrochloric acid and sucrose + sodium chloride solutions did not differ between trained rats and control rats. The results suggest that a sucrose + quinine solution has a perceived taste (as revealed by elicited orofacial reflexes) similar to alcohol and that the sucrose mixture is avoided by rats with alcohol aversions because it is unpalatable.

Animals↗

PubMedDate not supplied

Evaluating the palatability of alcohol for rats with measures of taste reactivity, consumption, and lick rate.

In two experiments, rats were presented with water and six concentrations of alcohol (0.5%, 3%, 6%, 9%, 12%, and 15%, v/v) under conditions of mild fluid deprivation. Their responses were measured using taste reactivity (fluids infused directly into the mouth), consumption, and lick rate (both in a voluntary drinking situation). Results in both experiments showed that the number of overall ingestive responses was relatively high and consistent across all alcohol concentrations and water; aversive responding was low for all solutions. During one-bottle, 10-min tests, rats consumed the three lowest concentrations of alcohol (0.5%, 3%, and 6%) and water at an equal level. There was an abrupt drop in the amount of alcohol consumed at 9% and a continued decrease at the two highest concentrations. Lick rates for alcohol (measured only in Experiment 2) fell into three general patterns: 0.5%, 3%, and 6% produced almost identical, negatively accelerating curves consistently above that of water which was linear; lick rates for 9% and 12% rose initially but, at approximately 2 min, became flat; the 15% solution produced a low lick rate throughout the 5-min period. There were significant correlations between lick rate and amount consumed but, contrary to expectations, no significant correlations were found between taste reactivity and the other two measures (consumption and lick rate). These results suggest that taste reactivity to alcohol solutions may be reflective of processes different from those that regulate licking behavior or actual consumption.

Alcohol Drinking↗