Figure 8.
Long-term changes in activity after high-frequency stimulus trains. The long-term responses of two pairs of neurons; each pair was recorded simultaneously during the same stimulus. a, c, e, Biphasic stimulation (each phase, 0.2 msec/40 μA; 600 trains of 140 Hz; 40 stimuli per train; 500 msec intertrain interval). b, d, f, Biphasic stimulation (each phase, 0.2 msec/40 μ A; 600 trains of 140 Hz; 10 stimuli per train; 500 msec intertrain interval). a, b, Raster display of the firing of all train repetitions; the gray lines denote the stimuli. c, d, PSTH of the response to the stimulation trains. Both the raster display and the PSTH are aligned to the first stimulus within the train and are in 1 msec bins. The sequence indicates the number of the neuron with spikes that formed the basis of the figure. e, f, PSTH of the period after the train: the original PSTH of the two neurons in 1 msec bins (gray solid and dotted line) and after smoothing using least squares quadratic polynomial fitting of 100 msec (black solid and dotted line); the PSTH is aligned to 10 msec after the last stimulus in the train.