Caudate stimulation prolongs latency of acoustically and visually signalled reaching in rats

Latencies of acoustically and visually signalled lateralized ballistic reaching were examined in rats with implanted electrodes in the caudate nuclei (Cd). Single pulse stimulation of Cd coinciding with CS onset increased the reach latency from 180 to 300 ms. Stimulation of Cd contralateral to the preferred forepaw was more disruptive than stimulation of ipsilateral Cd and the interference threshold was lower for Cd stimuli applied 100 ms after CS onset. Since reaching latencies were only moderately prolonged (by 85 ms) after electrolytic lesion of ipsilateral dentate nucleus. Cd stimulation does not only disrupt cerebellar preprogramming, but has a more general interfering effect.