(a) Schematic of SL and pyramidal (PYR) connectivity and input sources within piriform cortex (PCx). (b) Coronal sections from a Ntng1Cre/Ai14 mouse brain showing tdTomato labeling from anterior to posterior PCx. tdTomato labeling is restricted to superficial layer II of PCx. Scale bar is 200 μm. (c) Whole-cell current-clamp recordings were obtained from acute brain slices isolated from Ntng1Cre/Ai14 mice. Example voltage responses to direct current injections for a Ntng1+ (tdTomato+) cell. (d) As in (a). but for a Ntng1- (unlabeled) cell. (e) Resting membrane potentials of Ntng1+ and Ntng1- cells (Ntng1+: –65.4 mV [–70,–60], n = 11 cells; Ntng1-: –77.0 mV [–80.6,–72.9], n = 7 cells; p=5.27 × 10–4, unpaired t-test). (f) Input resistances of Ntng1+ and Ntng1- cells (Ntng1+: 541 MΩ [415, 669], n = 9 cells; Ntng1-: 166 MΩ [104, 243], n = 8 cells; p=2.15 × 10–4, unpaired t-test). (g) Membrane time constants of Ntng1+ and Ntng1- cells (Ntng1+: 32.1 ms [27.7, 35.8], n = 11 cells; Ntng1-: 13.6 ms [11.2, 16.0], n = 8 cells; p=1.29 × 10–5, unpaired t-test). (h) Burst indices of Ntng1+ and Ntng1- cells (Ntng1+: 1.16 [0.926, 1.41], n = 8 cells; Ntng1-: 4.57 [3.12, 6.19], n = 8 cells; p=1.43 × 10–4, unpaired t-test). (i) Coronal section of anterior PCx from an experimental Ntng1Cre/Ai14 mouse showing selective and robust expression of the inhibitory opsin, Jaws, in SLs. Scale bar is 200 μm. (j) Schematic of recording probe and optic fiber positioning for opto-tagging (left). Histology showing actual positioning of the recording probe and optic fiber in PCx after both were painted with DiI (right). (k) Raster plots with trials aligned to the onset of each light pulse for six example units that were later categorized as either Jaws+ (top) or Jaws- (bottom). (l) Distribution of spontaneous spike rates for SLs (blue, n = 426 cells) and PYRs (black, n = 464 cells).