Electrophysiological Characterization of V2a Interneurons and Their Locomotor-Related Activity in the Neonatal Mouse Spinal Cord

• DOI: 10.1523/jneurosci.4849-09.2010
• Publication Date: 2010-01-06T17:32:42Z
• Authors: Guisheng Zhong; Steven Droho; Steven A. Crone; Shelby Dietz; Alex C. Kwan; Watt W. Webb; Kamal Sharma; Ronald M. Harris-...
• Keywords: Tonic (physiology); Interneuron

The V2a class of Chx10-expressing interneurons has been implicated in frequency-dependent control left–right phase during locomotion the mouse. We have used Chx10::CFP mouse line to further investigate properties and locomotion-related activity isolated neonatal spinal cord. can be divided into three classes, based on their tonic, phasic, or delayed-onset responses step depolarization. Electrical coupling is found only between neurons same helps synchronize neuronal within class. Serotonin (5-HT) excites tonic by depolarizing increasing membrane input resistance, with no significant effects action potential properties, a mechanism distinct from 5-HT excitation commissural interneurons. During NMDA-/5-HT-induced locomotor-like activity, patch-clamp recordings two-photon calcium imaging experiments show that approximately half fire rhythmically ventral root-recorded motor activity; rhythmic fired one cycle, either ipsilateral contralateral L2 root bursts. percentage firing increases higher-frequency fictive locomotion, they become significantly more locomotor cycle; this may help explain shift Chx10::DTA mice, which lack these neurons. Our results together data accompanying paper (Dougherty Kiehn, 2009) reinforce earlier proposals are components hindlimb central pattern generator, helping organize coordination