Figure 5.

Biphasic to Monophasic Stimulation. (A): Current pulse waveform delivered during current-controlled biphasic stimulation from biphasic (left) to monophasic (right). (B): Voltage measured across electrode contacts showing progressive deviation from baseline with increasing charge unbalance. (C): Thalamic glutamate release measured during 10 sec (0.2 mA, 100 Hz, 100 μs pulse width), progressively unbalanced, stimulations shown in (A). (D): Peak glutamate responses elicited by progressively unbalanced biphasic stimulations relative to the peak glutamate response (set at 1) obtained from monophasic stimulation (n=3 rats). (E): Current pulse waveform delivered during current-controlled charge balanced stimulation from balanced (left) to monophasic (right). (F): Voltage measured across electrode contacts showing progressive deviation from baseline with increasing charge unbalance. (G): Thalamic glutamate release measured during 10 sec (0.2 mA, 100 Hz, 100 μs cathodic and 0-1ms anodic pulse width), progressively charge unbalanced stimulations as shown in (E). (H): Peak glutamate response elicited by progressively unbalanced biphasic stimulations relative to the peak glutamate response (set at 1) obtained from monophasic stimulation (n=3 rats). Black bar below each evoked response corresponds to the period of high frequency stimulation (HFS).