Behavioral effects of manipulation during different stages in the development of mice.

Abstract

C57B1/10J mice received shock or handling at either 1, 8, 15, 23, 30, 40, or 55 days of age. They were tested in an open field at 60 days and in an avoidance learning task at 85 days. A curvilinear trend existed with 23 and 30 day groups exhibiting highest defecation and reaching avoidance criterion fastest. No difference was found between shocked and handled Ss, although treated Ss had significantly higher defecation scores and superior avoidance scores than nontreated controls. The data tend to support the critical period hypothesis and suggest that these early treatments serve to increase later arousal.