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. Author manuscript; available in PMC: 2009 Jan 1.
Published in final edited form as: Brain Res Rev. 2007 Jul 31;57(1):118–124. doi: 10.1016/j.brainresrev.2007.07.008

Figure 5.

Figure 5

A: Simultaneous recording of 2 interneurons, an ON-unit and an OFF-unit, during 3 cycles of normal fictive rostral scratch in the turtle. Extracellular single-unit interneuronal recordings in the top trace; vertical lines in second trace represent timing of action potentials of the OFF-unit, the second-largest unit in the top trace; vertical lines in the third trace represent timing of action potentials of the ON-unit, the largest unit in the top trace; fourth, fifth, and sixth traces are ENG recordings from the biarticular knee-extensor, the monoarticular knee-extensor, and the hip-flexor motor nerves, respectively. The end of OFF-unit burst (marked with unfilled diamond) occurs near the start of ON-unit burst (marked with filled diamond) and near the start of knee-extensor bursts (marked with filled triangles). B: Plot of OFF-unit end-phase as a function of ON-unit start-phase. OFF-units are candidate members of the knee-flexor UBG; ON-units are candidate members of the knee-extensor UBG. From Stein and Daniels-McQueen, J Neurophysiol 90: 3585-3593, 2003a; used with permission of and copyright 2003 by the American Physiological Society.