Prefrontal lesions and avoidance reflex differentiation in dogs.

The effects of bilateral partial prefrontal lesions on go-no go differentiation with symmetrical or asymmetrical reinforcement trained by the avoidance procedure were investigated. Moderate impairment of these tasks was observed after large lateral or medial prefrontal lesions, while severe impairment after a deep incision of the fibers in the specific prefrontal region. It is suggested that the mechanism of avoidance differentiation is of a symmetrical type, which is directly related to the "motor act differentiation" but not to the drive-no drive differentiation.