Fig. 6: Inhibition shapes pyramidal odor responses.

a, Schematic of surgical preparation for Neuropixel recordings with GtACR2 optogenetic stimulation (image created with BioRender). Example brain slices from a PV-Cre and an SST-Cre mouse showing GtACR2 expression in PV and SST cells, respectively. Scale bar, 50 µm. Slice showing Neuropixel probe placement (stained with CM-DiI) in CA1 (bottom). b,c, Raster plots of putative pyramidal units across DNMS trials (b) or interneuronal and pyramidal units during the first odor (c). Only trials without optogenetic stimulation shown. Spikes colored according to each trial’s first odor (yellow, odor A; green, odor B). Lines in b depict odor A-specific fields. d, Average firing rates, relative to baseline, of pyramidal units (n = 5 mice, 17 sessions), stacked by mean odor response during the first DNMS odor (right). Dashed lines separate cells with positive and negative odor responses. Mean ± s.e. rates across cells with positive and negative odor responses (bottom). e, Top row shows mean ± s.e. firing rates throughout the first DNMS odor of pyramidal units with positive and negative odor responses and interneuronal units from PV-Cre mice (n = 19, 77, 10 units) in trials without versus with optogenetic stimulation (solid and dashed lines) applied during the interneuronal rebound window (blue bars). Interneuronal firing rates from voltage imaging shown for reference (black). Black marks indicate time points with significantly different rates (P < 0.05, two-sided WT, FDR across the odor). Right-side panels show mean ± s.e. rates across the odor, without and with stimulation (from left, P = 0.64, 0.002, 0.81; paired-sample two-sided t-test). Bottom row shows same for stimulation during the odor-onset window (n = 17, 79, 10 units. From left, P = 0.28, 0.008, 0.3). f, Same as e for SST-Cre mice (top row, n = 36, 103, 35 units. From left, P = 0.78, 0.1, 0.005. Bottom row, n = 34, 105, 35 units. P = 0.191, 0.014, 0.008). g, Pyramidal odor A (yellow) and odor B (green) fields, sorted as in d (only cells with fields shown). Dashed line as in d. Odor selectivity of field cells (dots; small jitter added for clarity) and mean ± s.e. across cells (line) (bottom). Odor selectivity of early fields versus post-hyperpolarization fields (<200 ms and >200 ms from odor-onset, respectively; n = 56, 124 units) (right). P = 1.13 × 10⁻⁵, left-tailed t-test. h, Mean ± s.e. firing rate around the first odor (dashed box in d), from pyramidal units with negative odor responses (red) and with positive odor responses and peak rates within (dark brown) or after the hyperpolarization window (light brown; <200 ms and >200 ms from odor-onset, respectively) (top). Mean ± s.e. interneuronal unit firing rates (middle). Mean ΔF/F and mean ± s.e. firing rates of pooled interneurons from voltage imaging (bottom). Vertical lines show same time points as in Fig. 5b,c.