Spontaneous and evoked activity of neurons in deep structures of the brain during their anodal polarization

The influence of anodal polarization on the spontaneous activity of neurons in the caudate nucleus, medial geniculate body, and the median center of the thalamus and on the evoked impulse activity of neurons in the medial geniculate body was investigated during auditory stimulation. The impulse activity was recorded extracellularly with glass and metallic microelectrodes. Nichrome polarizing electrodes of 0.2 mm diameter with an uninsulated tip of 0.3 mm were inserted into the foregoing structures in a packet. Current parameters evoking the reversible suppression of spontaneous and evoked neuronal activity were determined: 300-500 microA during exposure for 1-3 min at a distance of up to 3 mm from the polarizing electrode. After the cessation of polarization, a prolonged aftereffect was observed: The inhibition of evoked discharges lasted 4-10 min, and the evoked impulse responses disappeared for 5-20 min.