Fig. 5.

Cortical ripples modulate local single-unit spiking and synchronize high-frequency activity between distant regions. (A) Average cortical ripple broadband LFP and associated raster plot of PY and IN mean spike rates across ripples during NREM. Note the phase coupling of both PY and IN spiking to the ripple peaks. (B) Single-unit spike rates increase during cortical ripples compared to baseline, which was composed of randomly selected epochs in between ripples matched in number and duration (PY: n = 127, mean = 255%; IN: n = 38, mean = 297%; patients U1–3). (C) Single units are significantly phase-modulated by cortical ripples (PY: n = 32/66 significant; IN: n = 24/34 significant; binomial test between phases within 0 ± π/2 vs. π ± π/2, expected value = 0.5, minimum 30 spikes per unit across ripples). (D) Correlation of the >200-Hz analytic amplitude, a proxy for unit spiking, increases during waking coripples compared to randomly selected preceding control periods (within −10 to −2 s) matched in number and duration (n = 2,275 SEEG channel pairs from patients S1–17). ****P < 0.0001, two-sided paired t test. (E) Average >200-Hz amplitude correlation between coripples for each cortical channel pair does not decrement with fiber tract distance. PY, putative pyramidal unit; IN, putative interneuron unit.