THE DEVELOPMENT OF SWIMMING BEHAVIOR IN THE NEUROLOGICAL MUTANT WEAVER MOUSE

Weaver (wv/wv) mice have well-specified ontogenetic defects in both th e cerebellum and striatum, but have not previously been evaluated syst ematically for patterns of motor development. In this study, the effec ts of the weaver mutation were evaluated through an examination of swi mming behavior over the first 3 postnatal weeks. Detailed movement ana lyses of individual limb movements as well as interlimb coordination w ere used to evaluate the effects of the weaver mutation. Weaver mutant mice displayed a developmental lag in terms of swimming style relativ e to controls. They also displayed a generalized slowness in limb move ments during the swim, which correlated with the developmental onset o f use of a particular limb during the swim. However, basic motor patte rns in weaver swimming continue to exhibit good overall coordination t hrough the 3rd postnatal week, even though locomotor ataxia has become pronounced by this time. Our results indicate that specific and limit ed alterations in movement can be traced to very early in development (postnatal Day 3) in weaver mutant mice, a time at which the earliest biochemical and neuroanatomical deficits in these animals have been es tablished. Our results also emphasize the need for systematic contextu al analyses of movement to understand interlocking processes both in m ovement ontogeny and its disorders. (C) 1996 John Wiley & Sons, Inc.