Early isolation produces enduring hyperactivity in the rat, but no effect upon spontaneous alternation

Abstract

Rearing rats in isolation between 23 and 45 days caused a lasting increase in photocell-cage activity, even if the animals were subsequently rehoused in social groups until 125 days of age. In contrast to its effects upon activity, isolation had no effect upon spontaneous alternation in a Y-maze. This dissociation argues for caution in relating hyperactivity and reduced alternation to a unitary deficit in an inhibitory system.