PEN‐FIELD BEHAVIOUR IN RATS: EFFECTS OF HANDLING, SEX AND REPEATED TESTING

Abstract

The effects of pre‐weaning handling, sex and repeated testing on the open‐field behaviour of rats were consistent with existing reports and with the interpretation of the defecation and ambulation measures as inversely related indices of emotionality. The main finding replicated a report that although handled rats increase their ambulation with repeated testing in a fashion concordant with the observed drop in defecation, non‐handled rats show an initial decline followed by an increase. This latter effect is interpreted in terms of fear‐motivated escape behaviour on trial one, since non‐handled rats confine their activity largely to the periphery of the field on this trial and their exploration of an object placed in the centre of the field increases over trials in accordance with theoretical expectations.