Figure 5.

CSD events correspond to a resetting of the LFP phase. A, The distribution of LFP phases in the [7–11] Hz band, at a depth of 500 μm, as a function of time relative to the onset of CSD events. The LFP phase distribution is broad before the onset of CSD events (t < 0) but then sharpens dramatically as the CSD event unfolds. B, Periods of high LFP phase coherence are initiated during the same stimulus episodes as when CSD events typically occur. Top, Three seconds of the rock music stimulus. Middle, LFP phase in the [7–11] Hz band at a depth of 500 μm, over 25 repeats. Colors as in Figure 4E–H. Black circles denote the times of detected CSD events in the respective trials. Bottom, The coherence of LFP phases (shown in black for the [7–11] Hz band and gray for the wideband) relative to a probability histogram of the CSD events (shown in red). WB, Wideband. C, Black line, CSD-event-triggered phase coherence of the LFP phase in the [7–11] Hz band and at a depth of 500 μm. Gray line, Event-triggered coherence of the wideband LFP signal. The phase coherence values are temporally aligned to the times of CSD events (t = 0) and averaged across all events. The onset of the CSD event coincides with a rapid rise and subsequent decay in phase alignment, which takes ∼100–200 ms. CSD events therefore mark a transition from periods in which LFP phase is unreliable across trials to a period in which phase is reliably stimulus locked. All data in this figure are taken from a single example recording session (same as in Fig. 4) in response to the rock music stimulus.