Frontal lobe and motivation of learned behavior.

Dorsal prefrontal lesions in dogs elicit hyperreactivity in instrumental discrimination and perseveration in trained serial action pattern. Lateral premotor injury causes hyporeactivity in instrumental discrimination and prolongation of activity in the trained serial action pattern. When the dorsal prefrontal area was injured together with the premotor region the result was again hyporeactivity in instrumental discrimination and prolongation of activity in the trained serial action pattern. Instrumental discrimination and behavior in the serial action pattern changed in the same direction after a dorsal preffontal lesion and in fasting, or after lateral premotor injury and satiation, respectively.