SPATIAL PROCESSING AND EMOTIONALITY IN AGED NMRI MICE - A MULTIVARIATE-ANALYSIS

The goal of this study was to investigate possible relationships betwe en different aspects of behavioural decline in aged (17 months) NMRI m ice by a multivariate analysis. These mice presented defects in spatia l processing both in place learning in a Morris-type water maze and in spontaneous alternation in a Y-maze, as well as showing changes in th eir behaviour in the elevated plus maze test of fear/anxiety and open- field ambulation. Data were first factor analysed and then correlated on the basis of variable factor scores. The results showed clearly tha t age-related behavioural changes were independent of each other excep t between open-field activity measured over 6 min and spatial learning indices in the Morris-type water maze, in that mice performing poorly in the latter were more active in the open field, and between the rat io open/total arms visited in the elevated plus maze task and locomoto r activity during the first 2 min of the open-field test. It is propos ed that the notion of an allocentric or locale system cannot be applie d unitarily to both spatial learning and spontaneous alternation defec ts, and that activity levels in the aged mice are task dependent and r eflect different underlying factors.