Fig. 1: vGlut2BF neurons are odor responsive but do not show odor specificity.
A Schematic of GRIN lens implantation above the horizontal limb of the diagonal band (HDB) and Magnocellular Preoptic Nucleus (MCPO) in vGlut2-IRES-Cre mice injected with AAV-hSyn-FLEX-GCaMP8s. B Experimental setup for odor screening and in vivo calcium imaging with a Miniscope. C Representative field of view showing vGlut2BF neurons through the GRIN lens. Scale bar, 100 μm. D Extracted calcium traces from the 32 neurons shown in (C). E Heatmap of odor-evoked responses from all recorded vGlut2BF neurons for two example odors, Eugenol and Methyl Salicylate (MSC). Below each heatmap, population-averaged traces are shown for neurons categorized as excited (blue), non-responsive (black), or inhibited (green). The timescale matches between heatmaps and average traces. Black vertical lines indicate odor onset and offset. F Proportion of response types during odor presentation. Left: responses to Eugenol—excited (23.86%), inhibited (2.27%), non-responsive (72.73%). Right: responses to MSC—excited (21.59%), inhibited (3.41%), non-responsive (75%). (n = 176 neurons from 6 animals). G Distribution of odor tuning across the population. Right: proportion of all neurons grouped by the number of odors that elicited excitatory responses, including neurons that did not respond to any presented odor (n = 176 neurons). Left: distribution restricted to neurons classified as excited (n = 78 neurons), grouped by the number of odors they responded to. H Decoding accuracy for distinguishing odor pairs among the four tested odors. Accuracy was compared to chance level (0.5) using two-tailed Student’s t-tests with Holm–Šidák correction. Black circles indicate the odor pair used for the accuracy comparison. Pairwise comparisons: Rose oil vs. Eugenol (p = 0.75), Rose oil vs. MSC (p = 0.59), Rose oil vs. Anisole (p = 0.59), Eugenol vs. MSC (p = 0.65), Eugenol vs. Anisole (p = 0.57), MSC vs. Anisole (p = 0.59) (n = 6 animals). Data are presented as mean ± s.e.m. Illustration in (B) was created in BioRender. Chin, P. (2025) https://BioRender.com/74qwul9. Source data are provided as a Source Data file. Right panel in (A) is reprinted from The Mouse Brain in Stereotaxic Coordinates, 3rd edition, Paxinos G. & Franklin K.B.J., Figures 27, Copyright (2008), with permission from Elsevier.
