Neuron, volume 61 Supplemental Data

Transcription

1 Neuron, volume Supplemental Data The Excitatory Neuronal Network of the C Barrel Column in Mouse Primary Somatosensory Cortex Sandrine Lefort, Christian Tomm, J.-C. Floyd Sarria, and Carl C.H. Petersen

2 Supplementary Table Kinetics of uepsps. Presynaptic L L LA LB L L Latency (ms). ±.8. ±.. ±.8. ±..9 Rise-time (ms). ±..9 ±.9.7 ±.7.78 ±..99 Time-to-peak (ms). ±..7 ±.7.99 ± ±.9. Half-width (ms). ±.. ±.. ±. 8. ±. 9.8 Decay-time (ms). ±..9 ±.. ±.. ±. L Latency (ms). ±.. ±.7. ±..9.7 ±.7 Rise-time (ms).9 ±..9 ±.. ±..8 ±.8.7 ±. Time-to-peak (ms). ±.87. ±.. ± ±.9 Half-width (ms) 7. ±..7 ±.. ±.7.9 ±.7 7. ±.7 Decay-time (ms) 8. ± ± ±..9 ± 8..7 ±. Postsynaptic LA Latency (ms).7 ±.7. ±.. ±.. ±.9.8 Rise-time (ms).7 ±..78 ±..7 ±.8.99 ±.8 Time-to-peak (ms). ±.. ±.9 9. ±. 9. ±.7.7 Half-width (ms). ±.. ±.8. ±. 8.9 ±. 7. Decay-time (ms) 77 ± ± 8 7. ±.7..8 Latency (ms).9 ±.7.7 ±.9. ±.8.7 ±.. ±.9. Rise-time (ms).8 ±..8 ±.9.77 ±..7 ±.. ±.. Time-to-peak (ms) 8.8 ±.97.7 ± ±. 8.8 ±.7.8 ±..7 Half-width (ms).7 ± 8.. ±..7 ±.7. ±..9 ±..9 Decay-time (ms) 7. ±. 7. ±..7 ±.8 7. ±..8 ±.9 7. LB Latency (ms).78 ±..9 ±.9.8 ±..7 ±.. ±.. ±. Rise-time (ms). ±..97 ±.. ±..9 ±..8 ±..7 ±.98 Time-to-peak (ms). ±.99. ± ±. 8.9 ±.7.7 ±. 7. ±. Half-width (ms). ±. 9. ±.. ±..7 ±.. ±. 9. ±. Decay-time (ms) 9.7 ±.7 9. ±.8. ±..7 ±.. ±. 9.7 ±. L Latency (ms).87 ±..99 ±.. ±..77 ±.8 Rise-time (ms).9 ±.9.99 ±..9 ±.. ±. Time-to-peak (ms). ±.8.7 ±..7 ±.. ±. Half-width (ms) 9.9 ±. 9.9 ±. 9.8 ± ± 7.9 Decay-time (ms) 8. ± ±. 7. ±. ± 9.7 According to a post-hoc Dunn-Holland-Wolfe test (P<.) statistically significant differences were found for: Latency: L LA vs, L LB vs, L LB vs LA, L L vs, L L vs L L, L L vs, L L vs LA, L L vs LA LA, L L vs LB LB, L vs L L, L vs L L, L vs, L vs LA, L vs LA LA, L vs LB LB, L vs, L vs LA, LA L vs L L, LA L vs, LA L vs LA, LA L vs LA LA, LA L vs LB LB, LA LA vs. Rise-time: L LB vs L L, L LB vs L L, L LB vs L L, L LB vs L LB, L LB vs L, L LB vs L, L LB vs LA, L LB vs LA LA, L LB vs LB LB, L LB vs L L, vs L L, vs L L, vs L L, vs L, vs L, vs LA, vs LA LA, vs LB LB. Time-to-peak: L LB vs L L, L LB vs L L, L LB vs L, L LB vs L, L LB vs LA, vs L L, vs L L, vs L L, vs L, vs L, vs LA, vs LB LB, LA LA vs L L, LA LA vs L L, LA LA vs L, LA LA vs L. Half-width: L LA vs L L, vs L L, vs L L, vs LB LB, LA LA vs L L. Decay-time: vs L LB, LA LA vs L L, LA LA vs L LB, L L vs L LB.

3 Supplementary Table Reciprocal bidirectional synaptic connections do not occur more frequently than expected by chance in the mouse C barrel column. These results therefore differ from the observations of Song et al. () reporting enhanced reciprocity when examining synaptic connections specifically between thick-tufted layer pyramidal neurons in the rat visual cortex. The uniformity of the groups of neurons studied by Song et al. () might suggest that they belong to functionally related networks which might mutually enhance reciprocal connectivity, whereas the more diverse cell types studied here might belong to more different and specialised networks following different rules of cortical organisation. Connectivity Random chance reciprocity Measured reciprocity L 9. %.9 %.7 % L 8.7 %. %. %. %.9 %. % LA 9. %. %. % LB 7. %. %.7 % L.8 %. % %

4 Supplementary Table Coefficients of variation for uepsps. Presynaptic L L LA LB L L.9 ±..9 ±.. ±.8. ±.8. L. ±.. ±.. ± ±. Postsynaptic. ±.. ±.. ±.. ±. LA.9 ±.7. ±.. ±..8 ±..7 ±.9.7 LB. ±.8. ±.7. ±..7 ±.. ±.7. ±.8 L. ±..8 ±..9 ±.7.87 ±. According to a post-hoc Dunn-Holland-Wolfe test (P<.), statistically significant differences were found comparing: L L vs, L L vs L LB, L L vs L LB.

5 Supplementary Figure A B C Rise-time (-8%) peak amplitude Half-width exponential decay-time L L L L LB baseline time-to-peak ms mv 8 mv ms ms Latency D Latency E Rise-time F Half-width Presynaptic L L LA LB L Presynaptic L L LA LB L Presynaptic L L LA LB L L L L L L L LA LA LA LB LB LB L L L ms ms ms Supplementary Figure. Kinetics of uepsps. (A) Latency was measured from AP peak to uepsp onset. Rise-time was measured from % to 8% of the peak uepsp amplitude. Time-to-peak was measured from latency to peak. Half-width indicates the measured full-width at half-maximal response amplitude. Decay-time was the time constant obtained from a single exponential fit of 8% to % on the falling phase of the uepsp. (B) Example experiments showing differences in uepsp duration. An example synaptic connection between two neurons (red) has a longer duration compared to a different example experiment with a synaptic connnection from a neuron to a L neuron (blue). The traces have been scaled so that the peak of the uepsp has the same amplitude. (C) Example experiments showing differences in uepsp latency. An example synaptic connection between two L neurons (red) has a shorter latency than a different example experiment showing a connection from L to LB (blue). The traces have been scaled so that the peak of the uepsp has the same amplitude. (D) Color-coded matrix of layer specific uepsp latencies. (E) Color-coded matrix of layer specific uepsp rise-times. (F) Color-coded matrix of layer specific uepsp half-widths.

6 Supplementary Figure A L L L L ms mv. mv ms mv. mv LA µm B L ms mv. mv L L L L ms mv. mv LA µm ms mv. mv C L L LA LB L 8 mv ms mv ms 8 mv. mv LA LB 8 mv ms. mv L µm 8 mv ms. mv ms 8 mv. mv Supplementary Figure. Example excitatory synaptic connections in the mouse C barrel column. (A) Example experiment with one -> and two ->L connections. (B) Example experiment with one L->L and two L->L connections. (C) Same experiment as shown in Figure, showing two LA->LA; one LA->LB; one LB->LA and two LB->LB connections.

7 Supplementary Figure A L thickness 8 µm L thickness µm L % L % L L L % L % L L L µm L µm B Connection Probability Mean uepsp Product Presynaptic Presynaptic Presynaptic LA LB L LA LB L LA LB L LA LB L LA LB L LA LB L LA LB L LA LB L LA LB L LA LB L LA LB L LA LB L %. mv. mv Supplementary Figure. Layer and sub-layers. (A) Layer can be defined from DAPI stained sections as a band of higher density cells. A polynomial function was fitted to the fluorescence profile and a threshold of % of the rising and falling fluorescence intensity was used to define the L boundary. Quantified over 7 slices, we find a DAPI-density-defined layer thickness of 7 ± µm. (B) Functionally, the input to the upper µm of L appears different to the lower part of L. One could therefore propose a subdivision of L into LA (top µm of L) and LB (the lower part). The connectivity matrix is shown using these layer assigments. LA appears to communicate strongly and bidirectionally with LA.

8 Supplementary Figure A All x distance (µm) unconnected unidirectional bidirectional x distance (µm) -. % / µm r = -.9 x distance (µm) B L L LA LB L -.8 % / µm r = % / µm r = % / µm r = -.. % / µm r =.. % / µm r =.7 -. % / µm r = -. Supplementary Figure. Horizontal connectivity within the mouse C barrel column. (A) Pooling all intralaminar data. Distance between pairs of recorded cells in x (horizontal) and y (vertical) dimensions (left). Histogram showing distribution of cell pairs with respect to horizontal distance (center). Probability of finding synaptically connected cells as a function of horizontal distance together with linear best fit (right). Over the first 8 µm there is no significant effect of horizontal distance upon connectivity. (B) Same analysis, but now divided into each individual layer.

9 Supplementary Figure A Postsynaptic L B Postsynaptic L Number of connections per µv bin Number of connections per µv bin C Number of connections per µv bin Postsynaptic 8 D Number of connections per µv bin Postsynaptic LA E Number of connections per µv bin Postsynaptic LB 8 F Number of connections per µv bin Postsynaptic L Supplementary Figure. Distribution of uepsp amplitudes. (A-F) Histograms of uepsp amplitude distributions binned at µv intervals for all synaptic inputs recorded in postsynaptic neurons located in L (A), L (B), (C), LA (D), LB (E) and L (F). The best Gaussian fit is superimposed in red. The distributions deviate from Gaussian, showing a long tail indicating the presence of rare large-amplitude excitatory synaptic connections in all layers of the mouse C barrel column.

10 Supplementary Figure A Postsynaptic L B Postsynaptic L C D Postsynaptic Postsynaptic LA 8 E Postsynaptic LB F Postsynaptic L 8 Supplementary Figure. Coefficients of variation. (A-F) The coefficient of variation (the ratio of standard deviation to the mean) is plotted as a function of the uepsp amplitude for every synaptic connection found in this study divided into separate graphs depending upon the laminar location of the soma of the postsynaptic neurons.