Fig. 7: In vivo extracellular action potential (EAP) and functional properties of opto-tagged Pvalb and Sst neurons.
From: Associations between in vitro, in vivo and in silico cell classes in mouse primary visual cortex
a Light sensitive channelrhodopsin-2 (ChR2) channels were virally expressed in two inhibitory cell populations, Pvalb and Sst, in mouse V1 (dark green areas). The animals were then implanted with Neuropixels probes. b Example units responding to light activation (light blue regions) in V1. Top: spike rasters; Bottom: spike frequency. Left: a non-responsive unit; Middle: a light-responsive Pvalb unit; Right: a light-responsive Sst unit. c Examples of multi-channel EAPs of Pvalb units (dark blue) and Sst units (orange). Two of the units are the same ones as in panel (b) (boxes). d One-channel EAP features (trough-peak width: TPW; repolarization time: REP) for the Pvalb (dark blue, n = 24) and Sst units (orange, n = 18) from the optotagging experiments (inset: mean EAP waveforms; light gray: FS units, dark gray: RS units, from wild-type animals as in Fig. 2d). e Comparison of EAP properties between optotagged Pvalb (n = 24) and Sst (n = 18) units (top: one-channel properties; bottom: multi-channel properties). Box plots show the center line as the median and box limits as upper (75%) and lower (25%) quartiles. The whiskers extend from the box limits by 1× the interquartile range. Mann–Whitney U test, two-sided, **p < 0.01, ***p < 0.001. f EAP amplitude (left) and propagation (right) along the extracellular channels as a function of distance from the soma (taken as the channel with the largest EAP amplitude) for the optotagged Pvalb (n = 24) and Sst (n = 18) units (gray lines: individual units; colored lines: mean ± SD (standard deviation)). g Comparison of the symmetry index for Pvalb (n = 24) vs. Sst (n = 18) units (two-sample t-test, two-sided, p = 0.012). h Left: Comparison of response pattern during drifting gratings in the opto-tagging experiments (CV: coefficient of variation). Box plot representation is similar to that in panel (e). Mann–Whitney U test, two-sided, p = 0.0076, n = 24 Pvalb, n = 18 Sst; Right: spike-field coherency metric kappa and preferred spike phase of optotagged Pvalb and Sst for various LFP frequency bands. Data are presented as mean ± SEM (standard error of the mean). Mann–Whitney U test, two-sided, *p < 0.05, **p < 0.01, ***p < 0.001. Source data are provided as a Source Data file.
