[Different forms of potentials discharged by caudate nucleus neurons]

Background and evoked activities of the caudate neurons were recorded extracellularly in acute experiments on cats. Different forms of potentials were observed in background and evoked activity. They could be divided into three types: (a) simple full size action potentials; (b) prepotentials characterized by smaller amplitudes and slower decrement; (c) complex discharges consisting of simple potentials of smaller amplitude accompanied by slow positive-negative waves. Prepotentials were observed in background activity separately or as components of full size spikes. Frequency range of complex discharges was 0.5-1 per s. Prepotentials and full size potentials were arrested by slow waves of the complex discharges. The observations are discussed with regard to the origin of diverse forms of the potentials in the caudate nucleus neurons and compared to those made on the cerebellar Purkinje cells.