Premotor nonspiking neurons regulate coupling among motoneurons that innervate overlapping muscle fiber populatio

MARIANO RODRIGUEZ; CARLOS BERNARDO PEREZ ETCHEGOYEN; LIDIA SZCZUPAK

JOURNAL OF COMPARATIVE PHYSIOLOGY A-SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY

Springer Berlin

Lugar: Heidelberg; Año: 2008 vol. 95 p. 491 - 500

0340-7594

Recent work indicated that co-activity of diVerent motoneurons (MNs) in the leech can be regulated through a network that is centered on a pair of nonspiking (NS) neurons. Here, we investigate whether this eVect generalizes to diVerent types of MNs that display diVerential co-activity patterns in diVerent motor behaviors: the dorsal longitudinal excitors DE-3 and the dorsal and ventral excitors MN-L. The data indicates that both motoneurons are coupled to the NS neurons through rectifying junctions that are activated when the motoneuron membrane potential becomes more negative than that of the NS, and that they exert an inhibitory synaptic potential on NS via a polysynaptic pathway. In addition, DE-3 and MN-L are linked by junctions that allow mutual excitation but the transmission of excitatory signals from MN-L to DE-3 depended on NS membrane potential. The results support the view that NS neurons can play a central role in orchestrating the co-activity of MNs during motor behaviors.