Journal: Nature Communications

Article Title: The functional organization of excitatory synaptic input to place cells

doi: 10.1038/s41467-021-23829-y

Figure Lengend Snippet: a Schematic of experiments using 2P microscopy to image CA1 pyramidal neuron somatic firing patterns with jRGECO1a (red) and excitatory synaptic inputs to dendrites with iGluSnFR (green) during spatial behaviors in VR. b Example image of jRGECO1a fluorescence from labeled CA1 pyramidal neurons imaged during behavior. c Somatic jRGECO1a ΔF/F versus track position for each traversal of a single session (top) and mean ΔF/F versus position across all traversals (bottom) for three different neurons from different mice. Place cell at the left (cell highlighted in panel ( b )) with place field track location between dashed lines, silent cell in the middle, and active–nonplace cell at the right. Significant transients highlighted in bold. d Mean somatic jRGECO1a ΔF/F versus track position across all traversals of a single session for all recorded neurons (each row represents single-neuron mean ΔF/F). Plotted via cross-validation within each cell category. e Left, example z-projection image of iGluSnFR fluorescence from labeled CA1 pyramidal neurons imaged during behavior (same neurons and field of view as shown in panel ( b ). Right, top, mean images from time series acquired at two different single-imaging planes (from regions shown at the left). Right, bottom, same as top, but with 106 1-µm ROIs shown in green. Similar results were obtained in 54 sessions from 11 mice. f iGluSnFR ΔF/F vs track position for each traversal of a single session (top) and mean ΔF/F versus position across all traversals (mean ROI map, bottom) for five example ROIs shown in panel( e , right), from place cell shown in panels ( b , c ). Significant transients highlighted in bold. Place-ROIs: 29, 44, 70; Silent-ROI: 10, Active–nonplace-ROI: 56. g Mean iGluSnFR ΔF/F versus track position across all traversals of a single session (mean ROI map) for all ROIs (each row represents a single ROI mean ΔF/F) shown in ( e , right), from place cell shown in panels ( b , c ). Somatic place field track location between dashed lines. The percentage of ROIs in each ROI category also shown. Plotted via cross-validation within each ROI category. h , i . Same as panel ( g ), but for all ROIs from all 62 branches of all 23 place cells ( h ) or all 41 branches of all 23 nonplace cells ( i ). j Percentage of ROIs in each ROI category for place vs nonplace cells. Each circle represents a single branch. Mean ± bci across branches. (* p < 3.2e−3, likelihood ratio test, two-sided). n = 62 dendrites from 23 place cells from 35 independent sessions from 11 mice; n = 41 dendrites from 23 nonplace cells from 24 independent sessions from 11 mice. k Spatial dispersion of iGluSnFR transients in each ROI for all ROIs in place cells vs. nonplace cells (* p = 1.24e−4, likelihood ratio test, two-sided). l Mean amount of excitatory input per ROI per second (integral of all significant iGluSnFR transients in each ROI divided by recording time) for all ROIs in place cells vs. nonplace cells (* p = 9.1e−4, Rank-sum test, two-sided, place

Article Snippet: A low-titer Cre virus (AAV1- CaMKII -Cre, 1.51 × 10 8 GC/mL, Addgene) was injected (1 injection of ~60 nL at a depth of ~1250 µm below the dural surface using a beveled glass micropipette: ~1–2 MΩ after beveling) in combination with a high titer of flexed-iGluSnFR.A184S virus (AAV2/1- hSyn -FLEX.SF-iGluSnFR.A184S, 5.87 × 10 12 GC/mL) and flexed-jRGECO1a virus (AAV1- hSyn -FLEX.NES-jRGECO1a, 4.05 × 10 12 GC/mL), leading to expression of SF-iGluSnFR.A184S and jRGECO1a in a sparse subset of the CA1 pyramidal neuron population.

Techniques: Microscopy, Fluorescence, Labeling, Imaging