Figure 3.

Reciprocal modulation of ISN. Simultaneous recordings from the left (L) and right (R) M cells and selective activation of one of them. (A and B) A directly evoked spike (truncated, arrowhead) followed by a collateral IPSP and a burst of noise were produced in the right (A) and left (B) M cells. ISN was suppressed simultaneously in the opposite side. (C) Simultaneous extracellular recordings from the right (Upper) and left (Lower) axon caps (circled areas) from another experiment. Note the spontaneous alternation of firing in both axon caps (crossed arrow) and after a spinal stimulation (AD), which presumably activated only the right M cell (arrow).