FIG. 12.

TTX-induced changes to CR_ave,onset,H (pCAP) thresholds and waveforms. Upper panel: CR_ave,onset,H (pCAP) threshold changes that are comparable to those in Figure 3, though slower due to a slightly delayed changing of the injection rate relative to other experiments reported here: injection rate increased to 100 nl/min at 13.80 min and to 200 nl/min at 32.23 min. The arrows are a guide to when waveforms of associated color in the lower panel were acquired and are not meant to precisely quantify the sound level used to evoke the waveforms. Lower panel: CR_ave,onset,H (pCAP) waveforms to 8 kHz tone bursts at various times during an apical TTX injection experiment. Each of these responses was from a level 5 dB higher than the threshold. As time progressed and TTX flowed from the apex to base, the typical N₁P₁ (i.e., CAP) waveform morphed gradually into a negative potential with an earlier peak response latency (indicated by the vertical line). Such post-TTX CR_ave,onset,H (pCAP) responses are not from nerve action potentials and are hypothesized to be from EPSPs.