Fig. 1: Gain control in the visual cortex via serotonergic receptors.
a Schematics representing the localization and main modulatory synaptic effects of 5-HT2A receptors expressed in pyramidal and parvalbumin (PV) neurons in the mouse cortex. b 5-HT2A receptors are known to reduce the gain of visually evoked responses without affecting baseline levels of activity. c 5-HT2A receptor activation in populations of either pyramidal or PV neurons was controlled optogenetically by light. d Silicon probe recordings allowed source separation of responses of putative excitatory or inhibitory neurons based on analysis of waveform features (see “Methods” section). e Left to right: coronal slice of the mouse brain with V1 location marked; confocal scans of slices with mOpn4L-5-HT2A expression (green) in a NEX-Cre mouse, antibody against GluR2/3 (red) and the merged image. f Same as (e) for a PV-Cre mouse with antibody against PV (red). Arrows point to double-positive cells. The scans in (e, f) represent areas enlarged in Extended Data Fig. 3b and Extended Data Fig. 4a, respectively. g 2-Photon fluorescence images of V1 cortical slice from a NEX-Cre mouse showing expressing of mOpn4L-mCherry-5-HT2A (left) and GCaMP (middle) in pyramidal neurons, merged image (right). Images in (e–g) are representative of three independent experiments. h Time course of Ca2+-dependent changes in fluorescence during 3 min blue light activation under the influence of TTX/CNQX (n = 103 cells) or TTX/CNQX/U73122 (see “Methods” section) (n = 50 cells). Traces and shadings represent mean ± SEM. i Comparison of the amplitude of all cells depicted in (h) at the time of peak during TTX/CNQX and TTX/CNQX/U73122 applications. Box plots indicate median (middle line), 25th, 75th percentile (box), 10th, and 90th percentile (whiskers), ***p = 0.0007, two-sided Mann–Whitney U-test. Scale bars: 100 µm in (e), 50 µm in (f), and 25 µm in (g). Source data are provided as a Source Data file.
