Reinforcing effect of stimulation of the mesocerebral region of the brain of the edible snail.

Two regions of the brain of the edible snail were stimulated. The spontaneous movements, either opening or closing, of the opening of the mantle cavity served as the signal for the stimulation. The stimulation of the region of the mesocerebrum of the edible snail in a semi-intact preparation may serve as a positive reinforcement of intercurrent behavior, while stimulation of the rostral portion of the parietal ganglia may serve as a negative reinforcement. Depending upon whether the movement itself or its absence is reinforced, the change in the intercurrent behavior may change sign.