Figure 3.

Multiunit recording of lumbar interneurons from the superficial and deep dorsal horn. (A) The white and black circles represent the sites from which the multiunit recordings of the spinal neurons were performed. The white circles represent the superficial dorsal horn neurons. The black circles represent the deep dorsal horn neurons. (B) Distribution of the depth of the recorded interneurons (n = 37) shown in (A). (C) Scheme representing the spike-sorting for both the superficial and deep dorsal horn neurons, as indicated. Note that the superficial dorsal horn neurons exhibited a slower firing rate than the deep dorsal horn neurons. The signals from single interneurons were obtained from the raw multiunit activity (MUA). The waveforms illustrated in the left panel are superimposed traces of two interneurons from two different animals. The right panel shows the raster plots of such neurons in response to the high-frequency stretch of the Achilles tendon (uppermost trace and vertical bars).