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Dissociable onset of cognitive and motivational dysfunctions following neonatal lesions of the ventral hippocampus in rats.

Publication Type:

Journal Article

Source:

Behav Neurosci, Volume 122, Issue 3, p.629-42 (2008)

Keywords:

Age Factors, Analysis of Variance, Animals, Animals, Newborn, Choice Behavior, Cognition Disorders, Female, Hippocampus, Male, Maze Learning, Motivation, Pregnancy, Rats, Rats, Sprague-Dawley, Reaction Time, Reinforcement (Psychology)

Abstract:

This research examined cognitive and motivational processes at different developmental stages in rats with neonatal ventral hippocampus (VH) lesions, an approach used to model schizophrenia. In Experiment 1, performance in a T-maze alternation task was assessed on postnatal days (PNDs) 22 and 23. VH-lesioned rats displayed a severe deficit relative to controls. In Experiment 2, behaviorally naive rats were tested for spontaneous alternation at PND 29. Alternation was intact in VH-lesioned rats only when successive alternations were separated by >5 s. In Experiment 3, motivation was tested in a cost-benefit T-maze task and in a saccharine-water preference test. Between PNDs 22-37, behaviorally naive rats with neonatal VH lesions displayed weaker saccharine preference than controls, but the 2 groups did not differ on the cost-benefit task. At adulthood, between PNDs 56-72, the difference on saccharine preference persisted and an impairment on the cost-benefit task emerged. Overall, these results suggest that working memory deficits observed at the weaning stage were not secondary to spontaneous alternation or motivation dysfunctions.

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