[Electrophysiologic study of descending effects of field 5b of the association cortex of the brain of the cat on the neurons of the ventroposterolateral nucleus of the thalamus].

Responses of 65 thalamic ventroposterolateral (VPL) nucleus neurons to stimulation of the associative cortex (area 5b) were studied in acute experiments on cats anesthetized with ketamine (25 mg/kg) and immobilized with myorelaxine (2 mg/kg). Neurons studied were identified on the basis of peculiarities of their responses evoked by primary somatosensory cortex and medial lemniscus stimulation. Three neurons responded to stimulation of the area 5b antidromically. Primary orthodromic excitation and inhibition were observed in 17 (26.2%) VPL neurons. The role of the area 5b descending influences on the somatosensory impulses transmission through VPL relay neurons is discussed.