Reduced reelin protein synthesis in ventral hippocampus of isolation reared Wistar rats accompanies impaired avoidance conditioning.

Given that suppressed reelin protein synthesis is associated with cognitive dysfunction in both rodents and humans, we examined the ontogeny of these deficits in rats reared in isolation as a basis for understanding developmental emergence of neuropsychiatric illness. Isolation rearing exerted minimal effects on spatial learning other than to inhibit the transient learning improvement observed in social reared rats at postnatal day 60. By contrast, at postnatal day 80, animals reared in isolation were significantly impaired in an avoidance conditioning paradigm, a deficit that correlated with suppressed reelin synthesis restricted to the ventral aspect of the dentate gyrus. These findings suggest that environmental factors alone can impair forms of cognitive development with relevant region-specific dysfunctional plasticity.