Effect of a Nonspiking Neuron on Motor Patterns of the Leech

MARIANO JULIÁN RODRIGUEZ; RODRIGO JULIÁN ALVAREZ; LIDIA SZCZUPAK

JOURNAL OF NEUROPHYSIOLOGY

AMER PHYSIOLOGICAL SOC

Lugar: Bethesda; Año: 2012 vol. 107 p. 1917 - 1924

0022-3077

@font-face { font-family: "Times New Roman"; }@font-face { font-family: "Arial"; }p.MsoNormal, li.MsoNormal, div.MsoNormal { margin: 0in 0in 0.0001pt; text-align: justify; line-height: 150%; font-size: 12pt; font-family: "Times New Roman"; }table.MsoNormalTable { font-size: 10pt; font-family: "Times New Roman"; }div.Section1 { page: Section1; } Premotor and motoneurons could play regulatory roles in motor control. We have investigated the role of a premotor nonspiking (NS) neuron of the leech nervous system in two locomotive patterns: swimming and crawling. The NS neuron is coupled through rectifying electrical junctions to all the excitatory motoneurons examined. In addition, activation of motoneurons evokes chemically mediated inhibitory responses in NS. During swimming and crawling, the NS membrane potential (VmNS) oscillated phase-locked to the motor output. Hyperpolarization or depolarization of NS had no effect on swimming, but hyperpolarization of NS slowed down the crawling activity and decreased the motoneuron firing frequency. Depolarization of NS increased the motoneuron activity and, at stages where the crawling pattern was fading, depolarization of NS reinstated it. Future work will determine if NS is actually a member of the central pattern generator or a regulatory element.