Fig. 8.

Crossed responses in motoneurons supplying intrinsic hand muscle. A: antidromic activation from ulnar nerve at the wrist. Inset on the right shows location of intraspinal electrode eliciting the crossed response. B: mean intracellular response to contralateral intraspinal microstimulation (100-μA stimulus current). C: single-sweep intracellular potentials that contributed to the average in B. D: averaged cord dorsum potential response recorded simultaneously as B. Arrows indicate time of stimulation. E: same as A, but for a different motoneuron from an intrinsic hand muscle. F: mean intracellular responses to stimulation of the contralateral median nerve at the arm (3× motor threshold). The top trace shows the lack of response to a single shock the middle trace shows the EPSP response to a double shock to the contralateral nerve and the lowest trace shows the response to a triple shock to the contralateral nerve. G: averaged cord dorsum potential response recorded simultaneously as F for triple shock stimulation of the contralateral median nerve. Modified from Soteropoulos et al. (2013).