Polarization of caudate nucleus and excitability of neurons in motorsensory cortex.

Responses of neurons in the anterior sigmoid gyrus of the cat were found to be characterized by depolarization when the dorsal portion of the caudate nucleus was anodally polarized in reference to the ventral portion. Hyperpolarization responses were recorded when the dorsal portion of the caudate was cathodally polarized. The threshold of the hyperpolarization response was higher than the threshold of the depolarization response. These responses were synaptically evoked and might have been the result of spatial and temporal activation of the cells and fibers in the caudate nucleus and its related structures.