Fig. 11.

Evolution of glial transient negative potentials evoked by cortical stimulation during SW seizures. A, SW seizure induced by cortical stimulation close to the recording site (area 5) of a glia and d.c. field potentials (left) and expansion of three sweeps (marked with asterisks) to show the evolution of the intracellular negativity as a function of the progression of the seizure (right). B, Evoked potentials (n = 50). Stimuli were delivered at 10 Hz and continued beyond the period depicted atleft. The glial evoked response displays an initial transient negative potential followed by a steady depolarization. The transient negativity was practically identical to that recorded in the d.c. field potential, whereas the depolarization appeared reversed in the depth-EEG.