LAMINA-VII NEURONS ARE RHYTHMICALLY ACTIVE DURING LOCOMOTOR-LIKE ACTIVITY IN THE NEONATAL RAT SPINAL-CORD

The midsagittally-sectioned lumbar spinal cord with thoracic segments intact retains the capacity for locomotor-like activity. Intracellular recordings were used to characterize the activity and concurrently la bel lumbar neurons in lamina VII, an area previously implicated in the generation of locomotion. Sharp electrodes were shown to preferential ly impale larger neurons. These neurons undergo rhythmic voltage oscil lations, presumably synaptically driven, during locomotor-like activit y induced by bath application of N-methyl-D-aspartate and 5-hydroxytry ptamine. This supports the hypothesis that synaptic activity recruits neurons in lamina VII that are associated with locomotor behavior.