DIFFERENT EFFECTS OF THE MOTOR CORTEX LES IONS ON PRECISE AVOIDANCE AND ESCAPE REACTIONS IN DOGS

Effects of ablation of the forelimb area in the motor cortex on the pr ecise liftings of this limb were studied. Even inaccurate avoidance re actions to the sound signal did not recover spontaneously. In the cour se of retraining unregular reactions of insufficient amplitude could b e easily recovered but the precise reactions (both fast continuous and slow discontinuous) did not recover at least for half a year after th e ablation. On the contraty, the fast precise escape reactions (to the shock applied to the ''working'' limb and eliciting its unconditioned flexion) remained essentially unchanged, i. a. the ability to stop mo vement in the correct (previously learnt) position persisted. The abil ity to fix position of the flexed limb retained but in was less perfec t and did not improve. The ability to overcome unconditioned flexion ( in order to perform discontinuous extensor escape reaction) was severe ly and continuously (for a year) decreased. Visually guided placings o f the forepaw on a holded out hand of an experimenter recovered essent ially spontaneously and almost completely during a month.