THE ACTIVITY OF THE PUPILLOCONSTRICTORY CENTERS

Abstract

The activity of the pupillo-constrictory centers has been investigated by recording the action potentials in the short ciliary nerve or in the centers of the cat.1) A. single active unit of the short ciliary nerve in the cat shows in most cases a tonic activity consisting of impulses of 4-10 per second. In the monkey similar activity is also recognized.2) The completely deafferenated pupillo-constrictory centers are enable to discharge spontaneous impulses similar to those before the isolation of the midbrain.3) The increased electrical activity of the short ciliary nerve, lasting for the duration of illumination and adapting slowly, is produced by the retinal light illumination. The more the intensity of the stimuli, the greater the impulse frequency becomes, and with the strong illumination the prolonged after-discharges are observed.