ABSTRACT
During instrumental alimentary conditioning in cats the speed of reflex stabilization depended on the correspondence between the dominant leg's lateralization and the side of the lever, which the animal had to press in response to the signal. When the lever was on the side of the dominant leg, the speed of the conditioning was greater than in the absence of such correspondence. Functional switching off (KCl) of the cortex of any hemisphere at the stage of reflex stabilization does not disturb the instrumental reaction. The switching off of the dominant hemisphere at the stage of stable reflex disturb the instrumental reaction, but has no effect on more simple forms of conditioned behaviour, e. g. run to the feeding through in response to the signal.