Extended Data Fig. 3: V1 γ events are linked to the integration of dLGN input.

a: Schematic of laminar V1 recordings coupled to optogenetic activation of dLGN terminals in head-fixed mice on running wheel. Mice were injected 5–8weeks prior with AAV5-hSyn-hChR2-eYFP in dLGN. b: Histological slice showing ChR2-eYFP expression in dLGN. c: Schematic of laminar V1 recordings in head-fixed mice on running wheel coupled to optogenetic activation of inhibitory terminals from SST + TRN neurons. SST^Cre+ mice were injected 5–8weeks prior with AAV5-DIO-hChr2-eYFP in TRN and a fiber was implanted above dLGN. d: Histological slice showing ChR2-eYFP expression in TRN. e: Slice from the mouse in d showing the path of the implanted optic fiber ending above dLGN. f: Contiguous V1 slices from the mouse in d showing the site of recording stained with DiI. g: Modeling of the impact of discrete events on the LFP. Schematic of the approach: perfect pulse time series having value 1 at the time of pulses and 0 everywhere else are generated with a simulated sample rate of 1000 Hz. h: Excerpt (upper) and power spectrum (lower) of a regular 20 Hz pulse train. Regular trains have a comb-like spectrum. i: same as h for a Poisson distributed pulse train (λ = 20 Hz). Poisson distributed trains have a flat spectrum. j: same as h for a pulse train replaying γ events isolated by CBASS in an example mouse. The timing of γ events isolated by CBASS has energy in broad (30–80 Hz) and narrow-band (~55 Hz) γ activity. k, l, m and n: Same as g, h, i and j for simulated trains of synaptic events generated by the convolution of perfect pulses trains with an α function waveform. Convolution in the time domain translates to multiplication in the frequency domain. Synaptic waveforms produce a 1/f^α inflection to the spectrum. o: Schematic of laminar V1 recordings coupled to low intensity (1 ms; 1–5 mW/mm²) optogenetic activation of dLGN terminals in V1 of head-fixed mice on a running wheel. p: Average LFP power across channels outside (gray) and during optogenetic dLGN activation. Regular trains (20 Hz) induce comb-shaped frequency spectra (n = 4 mice). q: Same as p with a Poisson (λ = 24.3 Hz) distributed pulse train (n = 9 mice). r: Same as p with a pulse train having the natural temporal distribution of CBASS isolated γ events (Extended Data Fig. 2i; 24.3 Hz; n = 9 mice). s: Average CSD around low intensity optogenetic activation of dLGN terminals (left, blue dotted line) and around naturally occurring γ events (right, orange dotted line) on an example session. t: Cosine similarity between CSD evoked by low intensity activation of dLGN terminals and CSD around γ events or around a matched number of random events. The session in s is marked by a darker line (n = 9 mice). u: Average LFP and associated CSD profile in response to low intensity dLGN terminal activation in V1 (1 ms; 474 nm; 1–5 mW/mm²) during regular (20 Hz) pulse trains (n = 9 mice). v: Same as u with Poisson (λ = 24.3 Hz) distributed pulse trains (n = 9 mice). w: Same as u with trains having the natural temporal distribution of CBASS isolated γ events (Extended Data Fig. 2i; 24.3 Hz; n = 9 mice). x, y, z: Same as p, q and r during quiescence. aa, ab, ac: Same as p, q and r during locomotion. ad: Schematic of laminar cortical recordings in V1 in mice on running wheel coupled to modulation of dLGN through optogenetic activation of inhibitory terminals from SST⁺ TRN neurons (474 nm, continuous, 50 mW/mm²). SST^Cre+ mice were injected 5–8weeks prior with AAV5-DIO-hChr2-eYFP in TRN and a fiber was implanted above dLGN. ae: Average LFP power across channels outside (gray) and during light delivery (green) restricting analysis to quiescence (n = 9 mice). af: Rate of CBASS-detected γ events in V1 around light delivery in dLGN restricting analysis to quiescence (n = 9 mice). ag: Average V1 power in the γ range (30–80 Hz) during light delivery in dLGN restricting analysis to quiescence (n = 9 mice). ah, ai, aj: Same as ae, af and ag restricting analysis to locomotion. Error Bars: s.e.m; shaded areas: mean ± s.e.m.; black bar: statistically significant; **: p ≤ 0.01; ***: p ≤ 0.001. See Supplementary Table 1 for detailed statistics and Supplementary Table 2 for statistical samples.