Effects of medial thalamic damage on initiation of movement and learning

Rats with large medial thalamic lesions fail to avoid shock but perform relatively well in a shock-motivated brightness-discrimination task. The rats are slow to initiate exploratory behavior and slow to move from a small unfamiliar platform to a familiar table placed 3 in. away, although they perform normally when movements have begun. The results suggest that the medial thalamus plays a role in the triggering of movement apart from any role it may have in learning or the coordination of movement.