Radial-maze learning by lines of taste-aversion-prone and taste-aversion-resistant rats

Abstract

Lines of taste-aversion-prone and tas"te-aversion-resistant rats have been developed through 22 generations of bidirectional selective breeding for efficient or inefficient taste-aversion conditionability. The present study compared these two lines on food-reinforced foraging in a radialarm maze. The lines, although not identical on all measures taken, were equally adept at learning the maze. This finding supports prior indications that selective breeding has exerted an effect on learning that is highly specific to taste-aversion conditionability. Therefore, the genetically based line differences in taste-aversion conditionability cannot be attributed to a genetic difference in general learning aptitude.Nausea-based conditioned taste aversions (CT As) are acquired efficiently by rats and humans (Garcia, 1989). Nevertheless, considerable individual variability in CT A is observed within each species. For humans, individual differences in taste-aversion (T A) conditionability may modulate the effectiveness of nausea-based consummatory aversion treatments of alcohol and drug dependence (Elkins, 1980(Elkins, , 1991. Additionally, individual differences in CT A propensities may influence cancer patients' development of aversions to foods consumed in association with chemotherapy-induced nausea (Bernstein, 1978).The rat has been advanced as a useful T A learning model of nausea-based consummatory aversion therapies (Elkins, 1980;Logue, 1985). In an attempt to clarify possible genetic contributions to individual differences in T A learning propensities, Elkins (1986) undertook a program of CT A-based bidirectional selective breeding of SpragueDawley-derived rats. Selection was initiated at each of the two extremes of T A conditionability in randomly bred stock. At approximately 90 days of age, nonsibling matings were effected between the best learners and between the poorest learners of a cyclophosphamide-induced CT A to a normally preferred saccharin solution.An overview of the CT A methodology, which is detailed elsewhere (Elkins, 1986), is as follows: Fluiddeprived rats ingest a normally palatable saccharin solution and then are injected with cyclophosphamide. Cy- clophosphamide produces nausea in humans (Bernstein, 1978) and, presumably, elicits some comparable experience within rats, as indicated by its effectiveness as a T A conditioning agent. After a 3-day recovery period from the acute effects of cyclophosphamide, the rats begin 15 days of preference testing. During this assessment, they have contInuous access to the saccharin solution and to plain tap water. A daily preference score is computed that indicates the percentage to which ingestion of the saccharin solution contributes to total daily fluid intake . A subject's mean saccharin preference score, averaged over an interval of at least 3 days, has been the behavioral index of breeder selection.Line differences in T A conditionability appeared within the 2nd selected (S-2) generation (Elkins, 1986). Ongoing selection across 22 additional generations has p...

Genotype modulates age‐related alterations in sensitivity to the aversive effects of ethanol: an eight inbred strain analysis of conditioned taste aversion

“…Elkins et al (1992) observed that the selectively bred taste aversion prone (TAP) rats displayed a stronger ethanol-induced CTA response than taste aversion resistant (TAR) rats, despite the fact that ethanol CTA response was not a condition for selection. The TAP and TAR lines display similar abilities in other general learning paradigms, such as radial arm maze and bar pressing for food (Hobbs et al 1993;Orr et al 1997Orr et al , 2004.…”

High– and Low–Alcohol‐Preferring Mice Show Differences in Conditioned Taste Aversion to Alcohol

“…This hypothesis is supported by results of studies that have shown rats selectively bred for high CTA (taste aversion-prone rats) to the emetic agent, cyclophosphamide, demonstrate greater CTA to a wide variety of pharmacological agents, including alcohol (Elkins et al, 1992), and demonstrate decreased consumption and preference for alcohol than do their counterparts selectively bred for low CTA (taste aversionresistant rats) (Orr et al, 1997). Notably, these lines do not differ in other learning tasks that involve a motivational component, which indicates that the line differences in CTA sensitivity are not due to differences in general learning ability (Elkins, 1986;Hobbs and Elkins, 1983;Hobbs et al, 1993). It might be useful to test this hypothesis in HAP and LAP mice to determine whether the observed line differences in CTA are specific to alcohol or perhaps reflect differences in a general susceptibility to acquire CTA.…”

Conditioned taste aversion learning

“…For example, Elkins, Walters, and Orr 160 (see also Elkins 161 ) selectively bred animals from a population of Sprague–Dawley rats that developed either strong (taste aversion prone [TAP]) or weak (taste aversion resistant [TAR]) cyclophosphamide‐induced aversions. In later investigations, TAP and TAR rats were examined for differences in behaviors, such as rotation‐induced CTAs, ethanol‐induced loss of righting reflex and CTA, and radial arm maze learning, 160,162,163 to determine what other behaviors possibly correlated with an increased or decreased sensitivity to develop cyclophosphamide‐induced CTAs. Interestingly, these strains did not show reliable differences in standard learning preparations, such as the radial arm maze and bar pressing for food pellets, but they did show differences in cocaine‐ and ethanol‐induced CTAs, with TAP rats displaying more robust aversions with both of these drugs 160,164 .…”