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Biomedical subjects

C Guenaire

Publications and source records attributed to C Guenaire.

8 recordsLinked to original sources
PubMed1986

Psychophysiological profiles of the Roman strains of rats.

Male rats of the Roman High and Roman Low Avoidance strains were submitted to four principal behavioral tests: food-motivated acquisition of bar-pressing in Skinner box, delayed reinforced alternation, locomotor activity in a "multibox apparatus," conditioned suppression, and two biological measures: blood pressure and brain octopamine level. Performances of RLA and RHA rats were significantly different in each behavioral test. Blood pressure was higher in RHA, but the difference only approached the 0.05 threshold. As previously reported, brain octopamine levels of RHA rats were significantly higher than those of RLA. A multivariate treatment (analysis of correspondences) was applied to the data of 10 behavioral tests. The main factor extracted by this treatment clearly separated the two strains. Among the variables which best differentiate RHA and RLA rats, several do not involve stress (working memory, acquisition of bar-pressing, and locomotor activity).

Animals↗
PubMed1985

Differential acquisition of a "working memory" task by the Roman strains of rats.

Twenty-eight male rats of the Roman strains-fourteen RHA (Roman High Avoidance) and fourteen RLA (Roman Low Avoidance)-were submitted to a positively reinforced task, the delayed reinforced alternation test (DRA), in a T-maze. Performances of RLA rats were significantly better than those of RHA; RLA rats also had higher VTE (vicarious trial and error) and spontaneous alternation (SA) scores. These data confirm the fact that RLA may acquire positively reinforced learning as rapidly, or even more rapidly, than RHA rats, and that the differences in active avoidance behavior between these strains depend more on differential freezing behavior than on learning and memory capacities. Since the delayed reinforced alternation is considered as a working memory test, our results suggest that the Roman strains could be used as a genetic model for the neurobiological study of this form of memory.

Animals↗
PubMed1983

Brain octopamine and strain differences in avoidance behavior.

According to recent research, a significant relationship seems to exist between brain contents of p-octopamine and two-way avoidance responding in rats. Levels of this amine in hypothalamus and brainstem are higher in rats from the Roman High Avoidance (RHA) strain than in rats from the Roman Low Avoidance (RLA) strain. Intracerebroventricular administration of p-octopamine facilitates avoidance responding. The present paper reports the behavioral and neurochemical effects of p-octopamine administration on rats from the Roman strains. This treatment has no significant effect on cerebral levels of catecholamines, but it temporarily suppresses the strain differences in p-octopamine levels. In parallel, it also suppresses the strain differences in two-way avoidance conditioning, its facilitatory effect being much greater in RLA than in RHA rats. Avoidance behavior appears to be a useful model for the study of octopamine functions in the mammalian brain.

Animals↗
PubMed1983

Octopamine and locomotor activity of rats.

Intracerebroventricular administration of P-octopamine (OA) had opposite effects on locomotor activity depending on whether or not the rats were subjected to uncontrollable electric shocks. In unshocked rats, OA produced a large decrease in locomotor activity, but when the rats were subjected to unsignalled and uncontrollable electric shocks, a significant increase in locomotor activity resulted. The latter effect was observed either when the shocks were applied during the measurement of locomotor activity or when they were applied the day before (conditioned suppression paradigm). These results support the hypothesis of a neuromodulation of central noradrenergic transmission by octopamine.

Animals↗
PubMed1983

Two-way avoidance behavior of the roman rat strains following brain lesions.

Rats of the Roman strains, Roman High Avoidance (RHA), Roman Low Avoidance (RLA) and Roman Control Avoidance (RCA) were submitted to 5 conditioning sessions in a two-way shuttle box; the sessions were separated by a 24 hr-interval. Two indices were computed: a within-session progression index W and an inter-session progression index I. Index W was comparable in all three strains; index I was strongly negative in RLA and equal to zero or slightly positive in RHA rats. Lesion of the hippocampal commissure (HC) significantly facilitated CAR acquisition in RLA by making index I less negative: performances of RCA and RHA rats were unaffected. Lesions of the centro medianum parafascicularis nuclei of the thalamus (CM) significantly impaired acquisition of CAR in RCA and RHA by making index I more negative; performances of RLA rats were unaffected. Neither lesion altered index W. These results support the "freezing hypothesis" in the explanation of the Roman strain differences. They are in agreement with recent data on the emotional characteristics of the Roman strains and on the role of octopamine in avoidance behavior.

Animals↗
PubMed1982

[Spatial discrimination with thermal reinforcement in the young rat. (author's transl)].

Infant rats, because of their deficient thermoregulation, are very reactive to thermal stimuli. In our experiences, four to ten day old animals were trained a discriminative locomotor response between two places of a symmetrical device. A correct choice was reinforced by a 30-35 degree air stream during twenty seconds. One hundred and forty Wistar rats (male and female) were submitted to a twenty trial acquisition session (intertrial interval = 20 seconds). Those who reached a 70% correct criterion were trained to reverse their initial discrimination. Spontaneous alternation and "vicarious trial and errors" (VTE) were systematically observed. Percentages of correct responses in the two tests increased with age and reached a maximum in nine and ten day old rats. This increase was mainly due to a decrease of percentages of incorrect responses. Spontaneous alternation rate also progressed with age but did not reach adult level. VTE appeared in nine day old rats and were highly positively correlated with correct responses.

Aging↗
PubMed1982

[Operant conditioning with thermal reinforcement in the newborn rat].

In previous experiments, we studied the acquisition of instrumental locomotor responses reinforced by thermal stimuli, in one to ten-day-old rats. In these tasks, there was a precise topographic relation between the behavior to be conditioned and the reinforcement. In the experiment reported in the present paper, one to eight-day-old rats were tested in an operant conditioning task, where the operant (OP) was a non locomotor behavior, the raising of the head. At each day of age, two paired groups were compared: a "contingent" (C) and a "non contingent" (NC) group. Each OP (satisfying an amplitude criterion) of a C rat was reinforced by the application of a 30-35 degrees C air-stream during ten seconds. The NC rat of the same pair received the same number of air-streams during the session, but these stimuli were unrelated to its behavior. The duration of the session was ten minutes. Mean frequency of OP was higher in C than in NC groups, at one, two, six, seven and eight day of age. Absence of significant differences between C and NC groups at three, four and five days of age could be due to the competition between OP and the emerging locomotor behavior.

Animals↗