Autonomous Rhythmical Activity of Sense Organs

Abstract

LIKE the lateral-line organs of fishes and the receptors of the semicircular canals of the dogfish¹, the nerves supplying the ampullæ of Lorenzini in elasmobranch fishes exhibit a spontaneous discharge of impulses. The receptors of the lateral line can be excited to a higher frequency of discharge by a flow of fluid in the canal², and although there is no evidence that such a flow can actually occur except when artificially produced, the possibility cannot be entirely ruled out that some unidentified mechanical agency external to the receptor is responsible for the maintenance of a permanent state of excitation. Hoagland³, indeed, has argued that the spontaneous activity of lateral-line organs is due to a ciliary activity of the hair cells. It is therefore especially significant that a capsule containing a group of ampullæ of Lorenzini, with the nerve supplying it, can be isolated from a pithed ray, and can continue to discharge impulses spontaneously for more than 24 hours.