The spontaneous discharge of impulses from the lateral-line nerves of trout and catfish has been examined.
1. Broken endings of nerve fibers supplying receptors of the lateral-lines of trout and catfish may be the source of a repetitive discharge of nerve impulses.
2. This injury discharge occurs more frequently in trout and may mask the spontaneous discharge from the receptor cells. Experiments indicate that the latter discharge is not the result of injury.
3. The injury discharge ceases in from 10 to 15 minutes. The spontaneous receptor discharge in trout may continue for an hour if the circulation remains intact. The receptor response also fails in from 10 to 15 minutes after failure of the circulation.
4. The receptor discharge, the injury discharge, or the summed discharges frequently become synchronized. The excitability of the fibers of the nerve trunk appears to vary synchronously, so that nerve impulses initiated in fibers from tactile receptors not contributing to the spontaneous discharge can be conducted only during the part of the cycle occupied by the spontaneous discharge.