Figure 4.

Delayed onset of sustained activation of meningeal nociceptors, which was preceded by a short-lived surge of activity. A, An example of a CSD wave induced by chemical stimulation of the cortex (upper trace) that was associated an initial burst of neuronal firing, followed by delayed onset (gray area) of long-lasting (>51 min) activation of an Aδ-unit (bottom trace). Note that neuronal activity (numbers in parentheses) after CSD (pink) was approximately sixfold higher than baseline activity (green). Bin width = 10 s. B, Temporal relationship between waves of CSD and onset of neuronal activation. Note that delayed neuronal activation did not occur during the first 5 min. See Figure 2 A,B for further details.