Fig. 6.

Ultrasound (US)-induced depolarization correlates with a reduction in membrane resistance. A: a trial in which US (black bar) only induced hyperpolarization and there was no change in membrane resistance. The current injection pattern (bottom) is the same as that shown in Fig. 4. B: a trial in which US-induced depolarization was associated with a reduction in membrane resistance (black). C: isolation of US-induced depolarization and corresponding decrease in input resistance (R_in) by subtracting traces recorded in the absence of US (gray in A and B) from those with US application (black in A and B). Dashed trace in C was obtained from the trial in A where US induced only hyperpolarization and shows no change in the difference trace, or R_in, during the test current pulse (up and down arrows). The remaining 3 traces show that the amplitude of US-induced depolarization correlates with the magnitude of changes in R_in. Horizontal bar above the voltage traces indicates the timing of US stimulation. These recordings were obtained in the presence of tetrodotoxin (1 µM), 4-aminopyridine (200 µM), and ZD7288 (50 µM). All US-induced changes in depolarization and R_in were evoked by US bursts of the same intensity as that in Fig. 4.