Figure 1.

Identification of RCs. A, Transverse section of lumbar spinal cord showing GAD67–GFP-positive cells (a). b–d show enlargements of the ventral cord spinal with calbindin labeling in c and superimpositions of GFP and calbindin in d. Scale bars, 50 μm. B, Schematic of the recording setup. Suction electrode was used to stimulate and record the activity of the L2 ventral root ipsilateral to the recorded RCs. C, Visually guided patching of the GFP-positive cell located in the L2 ventral horn. a and b shows an GFP-positive cell before patch-clamp recording in bright-field (a) and fluorescent (b) images. c, The cell after filling with Alexa Fluor 488 dye in the pipette solution. D, Example of high-frequency firing of RCs evoked by ventral root stimulation. Such firing was typically evoked by electrical stimulation intensity two to three times higher than the stimulus to evoke a subthreshold EPSP in the RC. E, A schematic of how phase values (Φ) were calculated from the period (P) and the latency (L). Records from the i-L2 ventral root were full-wave rectified and smoothed with low-pass filtering. For details of circular plot measurements, see Materials and Methods.