PRIMARY AFFERENT DEPOLARIZATIONS OF SENSORY ORIGIN WITHIN CONTACT-SENSITIVE MECHANORECEPTIVE AFFERENTS OF A CRAYFISH LEG

Marchand, A. R., W.J.P. Barnes, and D. Cattaert. Primary afferent depolarizations of sensory origin within contact-sensitive mechanoreceptive afferents of a crayfish leg: properties, quantal analysis, and role in presynaptic integration. J. Neurophysiol. 77: 3340–3354, 1997. Recordings from the central branches of single identified dactyl sensory afferent (DSA) neurons in a crayfish in vitro preparation were performed to study modifications of the sensory message occurring before the first central synapse. These afferents comprised hairs and force-sensitive mechanoreceptors with phasic and phasotonic response characteristics in the terminal segment (dactyl) of the crayfish leg. More than one afferent spike size was often observed in intracellular recordings from these afferents, thus indicating the presence of electrical coupling between the central processes of DSA fibers. Additionally, in identified DSA fibers with large spike sizes, primary afferent depolarizations (PADs) of up to 15 mV were observed, ...