Figure 6.
Application of 5 nM TTX reduces phase locking to low frequencies. A, (i), Response to current-based cosines at average firing rates of 2 spikes/s under low conductance. Modulation amplitude was 7.5 pA. (ii), Response to current-based cosines at average firing rates of 1.5 spikes/s under high conductance. Modulation amplitude was 15 pA. Sinusoidal modulation at 8 Hz is indicated below the voltage traces in i and ii. (iii), Average spike phase histograms in response to 8 Hz modulation under low (black) and high (red) conductance. (iv), Vector strength vs. modulation frequency under low (black) and high (red) conductance. Tested modulation frequencies were: 0.1, 1, 4, 8, 12, and 20 Hz. B, Comparison between vector strength in the presence (large triangles) and absence (small squares) of 5 nM TTX under low (black) and high (red) conductance. Locking to low modulation frequencies is selectively reduced by TTX.