Multiple Gate Mechanisms Underlying Hierarchical Control of Behavior

Abstract

Behavioral acts are hierarchically organized so that a higher-order act either suppresses or facilitates lower-order ones to be released by specific sensory stimuli. By applying intracellular techniques to an unanesthetized whole-animal preparation, we analyzed neurophysiological mechanisms underlying the facilitatory control of uropod steering reflex during walking in crayfish. The descending sensory-motor pathway was found to be controlled by a multiple gate mechanism in which the sensory signals are amplified by a cascade of interneurons and transmitted to the uropod motor system only when the animal is engaged in walking. The gating signal is, at least partly, mediated by premotor nonspiking interneurons.