CHEMICAL AND ELECTRICAL SYNAPSES IN RECURRENT INHIBITORY CIRCUITS THAT CONTROL MOTOR OUTPUT

LIDIA SZCZUPAK

WASHINGTON

Simposio; ELECTRICAL SYNAPSES; 2017

JANELIA FARM, HHMI

Recurrent inhibition is a network mechanism by which the activity of motoneurons (MNs) exerts a negative feedback control onto other motoneurons, constraining their output level. In the leech nervous system this function is centered on a pair of nonspiking (NS) premotor neurons that form a tight network composed of electrical and chemical synapses. The pair of NS neurons is electrically coupled to all the excitatory MNs via rectifying junctions that are active when the transjunctional potential is negative at the NS side. In addition, MNs are connected to NS via hyperpolarizing chemical synapses. By virtue of this network, activation of MNs transmits inhibitory signals to other MNs that modulate the execution of motor patterns.