Fig. 3.

Voltage traces recorded intracellularly from hip-flexor (VP-HP) motor neuron (top trace in A) and hip-extensor (HR-KF) motor neuron (top trace in B) during normal fictive rostral scratch and during hip-extensor deletion fictive rostral scratch. In A and B, ENG recordings are from the monoarticular knee-extensor nerve (FT-KE; second trace), hip-flexor nerve (VP-HP; third trace), and hip-extensor nerve (HR-KF; bottom trace). A: hip-extensor motor neuron activity is deleted in first 2 cycles (marked with filled triangles), and the hip-flexor motor neuron intracellular recording shows corresponding deletion of hyperpolarization normally associated with hip-extensor activity (compare with last 3 cycles that show hip-extensor nerve activity). B: hip-extensor nerve activity is deleted in the first and third cycles (marked with filled triangles) and is associated with a complete absence of depolarization in the hip-extensor motor neuron intracellular recording (compare with cycles with hip-extensor nerve activity). Calibrations: 1 s, 20 mV. [Reprinted from Robertson and Stein (1988); used with permission of and copyright 1988 by The Physiological Society and John Wiley and Sons.]