Microelectrode study of accessory optic tract in the rabbit

Abstract

Microelectrodes were used to study the physiological properties of single units from the posterior accessory optic tract-transpeduncular tract in the rabbit. Both on and on-off elements were isolated in the nucleus of the transpeduncular tract. Only one off element was isolated. Intermittent photic stimulation was found to evoke a unique sequence of responses from the accessory optic system. The units gave a good response to the low rates of stimulation, decreased or stopped firing at the intermediate rates, and resumed firing at still higher rates of stimulation. The nucleus of the transpeduncular tract was found to receive its activation from elements in the central part of the retina. Recordings from elements of the nucleus of the posterior accessory optic tract showed that their physiological properties were very similar to those of the nucleus of the transpeduncular tract.