Abstract
The activity of the cilio-spinal centers has been investigated by recording the action potentials in the long ciliary nerve of the cat.
1) A single active unit of the long ciliary nerve shows a tonic activity consisting of impulses of 1-2/sec.
2) The cilio-spinal centers isolated completely from other central nervous systems and the afferent nerves are able to discharge autochthonous impulses.
3) The impulse discharge from the isolated cilio-spinal centers is inhibited by intravenous administration of adrenalin, but accelerated by asphyxia.
4) The spontaneous discharges led from some fibers of the long ciliary nerve are reflexly inhibited by retinal light illumination, and the inhibitory response becomes remarkable with the increase of the light stimulus, whereas the impulse discharge led from other fibers remains unchanged. The former is the fiber innervating the radial muscles of the iris and the latter is probably the fiber innervating the ocular arteries.
