Fig. 1. 4 Hz and 8 Hz oscillations differentially modulate local BLA spiking activity.

a Experimental schematic. Thirty two channel tetrode drives were implanted into the BLA to extract both LFP and spiking activity in mice while subjected to fear conditioning and extinction. b Example histology image showing tetrode placement after electrolytic lesion. c Averaged BLA power spectra during freezing and non-freezing periods used for phase-locking analysis. Inset: quantification as 4:8 Hz power ratio (paired two-tailed t-test: P = 0.0007, t(6) = 6.31, n = 7 mice). d Example BLA single units that significantly phase-locked (PL) to BLA LFP at 4 Hz during freezing or 8 Hz during non-freezing (significance based on permutation test P < 0.05; see Methods section). e Comparison of proportion of BLA single units that significantly phase-lock (based on permutation test P < 0.05; see Methods section) to 4 Hz only, 8 Hz only, both, or neither during freezing vs. non-freezing behavior (Chi-square test: X²(3, n = 106 units) = 30.12, P < 0.0001). f Averaged PPC spectra of units that phase-lock to 4 Hz during freezing (n = 25 cells) or 8 Hz during non-freezing (n = 22 cells). g Percentage of BLA single units that exclusively phase-lock to 8 Hz during non-freezing, a distinct subset that exclusively phase-lock to 4 Hz during freezing, and a third group that switches between the two (percentage of all significantly phase-locked units, n = 63 units). All error bars and shaded area: mean ± SEM.