ELECTRIC RESPONSES DERIVED FROM THE SUPERIOR CERVICAL GANGLION WITH MICRO-ELECTRODES

Abstract

The electrical activity of the superior cervical ganglion of cats and rabbits was studied with micro-electrodes, a capacity-coupled, push-pull amplifier and a cathode-ray oscillograph. "Axon-like" spikes appear during preganglionic stimulation or as an injury discharge with micro-electrodes of 7 to 10[mu] apertures. The spikes are postsynaptic phenomena of all-or-none character with a duration of 1.5 to 2 msec. They are found dispersed over the time range corresponding to the standard ganglionic record. The brief duration, sharp localization and all-or-none character of the spikes recorded with the smallest micro-electrodes suggest that they are derived from single cells. The single-spike potentials during a successive stimuli and with an unaltered position of the micro-electrode shows variations of latency as great as 7 msec. In some cases the frequency of response is largely independent of the frequency of the preganglionic stimuli. The "axon-like" spike is followed by 1 negative and 2 positive after-potentials, the last being identical with the slow positive after-potential of the ganglionic record.