CONVERGING ELECTRORECEPTOR CELLS IMPROVE SENSITIVITY AND TUNING

We studied the effect of convergent clustering of ampullary electrorec eptor organs on stimulus transduction and transmission in the catfish Icalurus melas by electrophysiologically recording primary afferent ac tivity of single ampullae (singlets) and pairs (doublers) innervated b y the same afferent. Doublers were twice as sensitive as singlets, and showed sharper tuning around the best frequency. The slope of the pha se curve in the doublers was slightly steeper than in the singlets. Th e spontaneous activity and scatter in interspike interval were not cor related with clustering. The implications of these findings for signal averaging in sensory neurons and their relevance for behaviour are di scussed. (C) 1997 IBRO. Published by Elsevier Science Ltd.