Effect of practice on paw preference in a reaching task in cats.

Paw preference and performance were analyzed in twelve male adult cats during early and late practice of a complex visuo-motor reaching task towards a moving target. A strong bias towards left paw use was seen early in training: 80.7% of the trials being performed with the left paw, and left pawed cats (n = 11) significantly outnumbered right pawed cats (n = 1). After practice, a shift was observed towards right paw use, in that, overall, the proportion of trials executed using the left paw fell to 71.4%. Moreover two of the left pawed cats modified strongly their preference: one shifted to exclusive use of the right paw while the other one became ambidextrous. In non exclusive cats the comparison of visuo-motor scores for left and right paws during late practice showed that the usage of the paw which is both faster and more accurate had increased during training whether or not that paw was initially the preferred one. Furthermore, for cats where no systematic performance advantage was seen (i.e. one paw was faster, the other one more accurate) there was a shift towards ambidextry. As a conclusion, the results confirm a bias towards left paw use in cats performing a complex reaching task, and show that this bias is weakened by practice. The left hemisphere could take more importance when the new visuo-motor activity becomes progressively a well routinized one.