[Participation of neurons from symmetrical parts of the sensomotor cortex in conditioned reflex activity].

Spike activity of the symmetrical points of the sensorimotor cortex was studied in the course of formation and extinction of a defensive conditioned reflex in cats. In the process of pairings the impulse responses in the hemisphere contralateral to the paw stimulated with electric current (reinforcement) increased, and were inhibited in the ipsilateral hemisphere. Extinction of the reflex or functional switching off of the contralateral hemisphere restored the conditioned reactions of the ipsilateral hemisphere neurones. An assumption has been made that conditioned connections appear in both hemispheres, but under ordinary conditions the reactions are ensured by the dominating (in learning) hemisphere. If it is switched off, a duplicate conditioned connection appears in the other hemisphere, as one of the mechanisms providing for the reliability of manifestation of the conditioned relfex.