Figure 3

Neuronal excitation in the spinal cord slices. Neuronal excitation in the spinal cord slices in control rats, rats injected with complete Freund adjuvant (CFA), and rats subjected to peripheral nerve injury (PNI). A, Schematic of a transverse spinal cord slice. Images in B were obtained from the area indicated by the green rectangle in A. B, Images in the left column are representative examples of optical responses elicited by a single-pulse stimulation to the dorsal root at the peak time point. The percent change in light absorption is depicted by simulated color, as indicated by the color bar. Graphs in the right column are representative examples of time courses of optical responses. Each time course was indicate examples of time courses of optical responses. Each time course was an average of 128 optical responses recorded by 16 × 16 pixels on the image sensor in the dorsal horn indicated by the black rectangle in each image. Stimulus pulses were administered at the time indicated by the filled triangle. C, Mean intensity of optical response. The intensity of each response was obtained by temporal integration of optical response magnitude during the 18-ms period after the onset of response. Data are expressed as % of mean intensity of optical response in control, untreated rats. *P < 0.05, **P < 0.01.