Figure 8.

Auditory responses during slow wave ON (active) and OFF (silent) periods. Comparison between responses to 100 msec tone pips during slow waves. (A) Mean A1 local field potential (LFP, top) and A1 multiunit activity (MUA, bottom) responses evoked by low- (30 dB), medium- (55 dB), and high-intensity (80 dB) tone pips. Red/blue traces correspond to OFF/ON periods. Green lines indicate sound onset (vertical) and duration (horizontal), and arrows point to differences in baseline firing between the two conditions. (B) Representative single-unit auditory responses to each volume intensity. In each quarter: spike raster plots and peristimulus time histogram (PSTH) show single-unit responses separately for different volume conditions. Green horizontal bars denote sound stimulation. Yellow boxes mark neuronal OFF period (left) versus neuronal ON period (right), and Δ (in red) specify the change in peak response (OFF divided by ON period). Note that the prestimulus baseline shows clear differences between ON and OFF periods (as expected), and a negative interaction exists between slow wave phase and sound intensity.