Sensomotor Organization of Motor Acts in the Cockroach <Emphasis Type="Italic">Periplaneta americana</Emphasis>

The experimental data are presented which indicate modulating effects of different sensor inputs on impulse activity of identified motoneurons included in the neuronal module regulating walking rhythm in the American cockroach Periplaneta americana. At a light stimulation of complex eyes in the cup and α-lobe of mushroom bodies (MB) and in the adjacent neuropil there are revealed neurons differentiated by their ability to reproduce stimulation rhythm, by the latent period of impulse response, and by intensity of summation effect in the case of bimodal stimulation—light and tactile. Data of extracellular marking of these neurons with cobalt ions are presented, which indicate the existence of direct connections between MB and optic lobes in the American cockroach protocerebrum. There are discussed morphological and electrophysiological characteristics of the system of descending dorsal connective fibers that participate in transmission of descending influences of head ganglia on segmental motor centers as well as functional unity of associative structures of the subesophageal ganglion that integrate interganglionary and neuronal modules if the III thoracic ganglion that form as a whole the hierarchically organized distributed system.__________Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 3, 2005, pp. 247–253.Original Russian Text Copyright © 2005 by Lapitskii, Nikitin.To the 100-anniversary of A.K. Voskresenskaya