Journal: Nature Communications

Article Title: Anatomically and functionally distinct thalamocortical inputs to primary and secondary mouse whisker somatosensory cortices

doi: 10.1038/s41467-020-17087-7

Figure Lengend Snippet: a Schematic showing the strategy used to selectively express ChR2-eYFP in FO or HO subdivisions of POm. Method used to activate thalamocortical axons expressing channelrhodopsin-2 in order to evoke postsynaptic potentials in the somatosensory cortex is illustrated. A 470 nm wavelength light was delivered with a LED light source coupled with a 1 mm optic fiber onto wS2. Inset: Two-photon microscopy image of an in vitro whole-cell patch–clamp recording of two neurons filled with Alexa 594. b Confocal z-projection of wS2 in a parasagittal slice after fixation. ChR2-eYFP was expressed in POm-FO axons, and recorded neurons were filled with biocytin followed by staining with streptavidin conjugated to Alexa 647. This experiment was repeated in three mice with similar results. c Light-evoked excitatory postsynaptic potentials (EPSPs) from recorded neurons labeled in b following 1 ms light pulses. d Top: Peak amplitude of EPSPs evoked by optogenetic stimulation of POm-FO axons recorded in cortical excitatory neurons ( N = 3 mice, n = 39 neurons) across different layers in wS2. On each box, central mark indicates the median and edges indicate 25th and 75th percentiles. The whiskers extend from the minimum data point comprised within 1.5× of the interquartile range to the 25th percentile and from the maximum data point comprised within 1.5× of the interquartile range to the 75th percentile. Bottom: same responses normalized to the average peak EPSP recorded in the main input layer (L4) for each experiment. e – g Same as b – d but for POm-HO axon stimulation during whole-cell recording of neurons in wS2 ( N = 3 mice with similar results, n = 34 neurons). Here, EPSPs were normalized to the average peak EPSPs from L5A neurons for each experiment.

Article Snippet: Sensory stimulation and behavioral training were performed through a Matlab-based (Mathworks, USA) custom-made software.

Techniques: Expressing, Microscopy, In Vitro, Patch Clamp, Staining, Labeling

Journal: Nature Communications

Article Title: Anatomically and functionally distinct thalamocortical inputs to primary and secondary mouse whisker somatosensory cortices

doi: 10.1038/s41467-020-17087-7

Figure Lengend Snippet: a Schematic of viral vector injection and microprism implantation for in vivo calcium imaging of thalamocortical axons expressing GCaMP6s. b Intrinsic optical signal in wS1 during whisker stimulation. This experiment was repeated in 14 mice with similar results. c Two-photon image of VPM axons in wS1. Similar results were observed in three mice. d Left: Example of a region of interest for axonal segments with high calcium signal correlation in wS1 (red). Right: Corresponding calcium responses to C2 or B2 whisker stimulation in z -score across trials. The average calcium responses are shown below. e Normalized calcium responses averaged over all axons for each population (3 mice, n = 62 axons for VPM-FO; 3 mice, n = 101 axons for POm-FO; 8 mice, n = 86 axons for POm-HO). Inset: Response latency comparison (Kruskal–Wallis two-sided test with Bonferroni correction, ** p = 0.008 for VPM-FO vs. POm-FO, ** p = 0.004 for VPM-FO vs. POm-HO, p = 1 for POm-FO vs. POm-HO). Boxplot: central mark indicates the median and edges indicate 25th and 75th percentiles. Whiskers extend to the largest or smallest point comprised within 1.5× of the interquartile range from both edges. f Left: Two-photon image of the calcium response (Δ F / F ) for C2 (green) and B2 (red) whisker stimulation overlaid on top of VPM axonal innervation (gray) in wS1. Middle: Distribution of whisker selectivity indices for the corresponding axonal population (3 mice, n = 62 axons). Right: Distribution for the absolute value of the whisker selectivity index. Red arrow: average value. g Same as f , but for POm-FO axons in wS2 (3 mice, n = 101 axons). Inset in the right panel: Response latency comparison between tuned (|WSI | ⩾0.75) and untuned (|WSI | < 0.75) axons (Kruskal–Wallis two-sided test, ** p = 0.002). Boxplot statistics same as in ( e ) inset. h Same as f , but for putative POm-HO axons located in layer 1 (8 mice, n = 86 axons). Kruskal–Wallis test with Bonferroni correction comparing |WSI | : p = 0.003 for VPM-FO vs. POm-FO; p = 4 × 10 −11 for VPM-FO vs. POm-HO; and p = 4 × 10 −11 for POm-FO vs. POm-HO.

Article Snippet: Sensory stimulation and behavioral training were performed through a Matlab-based (Mathworks, USA) custom-made software.

Techniques: Plasmid Preparation, Injection, In Vivo, Imaging, Expressing, Whisker Assay, Comparison

Journal: Nature Communications

Article Title: Anatomically and functionally distinct thalamocortical inputs to primary and secondary mouse whisker somatosensory cortices

doi: 10.1038/s41467-020-17087-7

Figure Lengend Snippet: a Schematic of a mouse performing a two-whisker discrimination task, and the average lick rate over all imaging sessions (>4 days of training) for all stimulus conditions across mice (mean lick rates over n = 14 mice, Kruskal–Wallis test with Bonferroni correction: p = 0.02 for C2 vs. B2; p = 2 × 10 −8 for C2 vs. No stim; and p = 0.009 for B2 vs. No stim). Boxplot: central mark indicates the median and edges indicate 25th and 75th percentiles. Whiskers extend to the largest or smallest point comprised within 1.5× of the interquartile range from both edges. b Calcium responses ( z -score) for an example VPM-FO axon during lick trials upon C2 or B2 whisker stimulation. Trials are ordered according to lick reaction times, which are shown with a white line on color maps. Average responses are shown below for lick and no-lick conditions. c Same as b , but for a POm-FO axon. d Left: Calcium responses averaged over all VPM-FO axons with significant responses to whisker stimuli during lick and no-lick trials, normalized to the no-lick condition. Dark lines: mean value and shaded areas: s.e.m. Middle: Early phase of the response over the first 0.4 s. Right: Comparison of the response amplitude between lick and no-lick conditions averaged over gray area (0–0.266 s) in middle panel (Wilcoxon paired two-sided test, p = 0.94, N.S. not significant). e , f Same as d , but for POm-FO axons (*** p = 3 × 10 −5 for ( e )) and POm-HO layer 1 axons (*** p = 1 × 10 −5 for ( f )), respectively. g Distributions of Pearson correlation coefficient between reaction times and calcium response latencies for all axons with significant responses in lick trials ( n = 169 for VPM-FO, n = 264 for POm-FO, n = 281 for POm-HO layer 1 axons). Colored bars: Pearson coefficient with p < 0.05. h Distributions of whisker selectivity index absolute values comparing all axonal populations and lick/no-lick conditions for axons with significant sensory responses in no-lick condition (Kruskal–Wallis two-sided test with Bonferroni correction; VPM-FO: *** p = 1 × 10 −12 for lick vs. no-lick, POm-FO: p = 0.32 for lick vs. no-lick N.S. not significant, POm-HO: *** p = 3 × 10 −10 for lick vs. no-lick, * p = 0.034 for VPM-FO vs. POm-FO in lick condition, *** p = 5 × 10 −15 for POm-FO and POm-HO in lick condition). Boxplot statistics as in ( a ).

Article Snippet: Sensory stimulation and behavioral training were performed through a Matlab-based (Mathworks, USA) custom-made software.

Techniques: Whisker Assay, Imaging, Comparison