Article Figures & Data
Figures
- Figure 1.
DSGCs with asymmetric dendrites exhibit more asymmetric inhibition but similar temporal offset compared to DSGCs with symmetric dendrites. A, Left, Skeletonized vDSGC (orange) and nDSGC (blue). Right, Summary data comparing dendritic asymmetry of vDSGCs (n = 23) and nDSGCs (n = 16) as measured by the magnitude of the vector from the soma to COM of the ON (filled) and OFF (open) dendrites. Red data points indicate the measurements for example cells on the left. Statistical significance assessed by one-way ANOVA (p = 4 × 10–4) and Dunn–Sidak post hoc test (**p < 0.01). B, Example tuning curve and mean traces of the IPSCs in vDSGCs (orange, left) and nDSGCs (blue, right) in response to a moving bar stimulus. ON (solid lines) and OFF (dashed lines) tuning curves and vector sums are based on peak current amplitudes. C, Left, Scatter plot of the peak amplitude of IPSCs in response to preferred versus null direction motion in vDSGCs (orange) and nDSGCs (blue). SEM for ON (dark shade) and OFF (light shade) responses indicated on the plot. Right, Summary data presenting the tuning of vDSGCs (orange) and nDSGCs (blue) as measured by the direction selectivity index. ON (filled) and OFF (open) responses separately. Unity line (gray dashed) indicating where preferred (PD) = null (ND) IPSC peak amplitude. Statistical significance assessed by Wilcoxon rank-sum test (**p < 0.01, ***p < 0.001). D, Example IPSC and EPSC traces in response to the preferred direction (PD, top) and null direction (ND, bottom) for a vDSGC (orange) and a nDSGCs (blue). Arrows indicating peak timing for IPSCs (magenta) and EPSCs (green). E, Summary data representing spatial offset based on the timing differences of the peak excitatory (E) and inhibitory (I) currents in response to preferred direction (PD) and null direction (ND) stimulation for ON (filled) and OFF (open) responses in vDSGCs (orange) and nDSGCs (blue). Statistical significance for nDSGCs assessed by paired t test (p > 0.05).
- Figure 2.
vDSGCs and nDSGCs have similar spatially offset inhibition and exhibit strong local correlations in excitation and inhibition. A, Example vDSGC (top) and nDSGCs (bottom) receptive field displaying mean inhibitory and excitatory postsynaptic responses for each stimulus presentation. Asterisk in the center of the stimulus field denotes soma location. ON (cyan) and OFF (purple) dendritic skeletons are overlaid. Inset shows stimulus presentation of 30 × 30 μm light within a 50 × 50 μm area to evade scattering effects. B, Heat map of dendritic density (left), the EPSC peak current amplitude (middle), and IPSC peak current amplitude (right) for ON (top) and OFF (bottom) responses of the example vDSGC (top row) and nDSGC (bottom row) to the left. Scale bar: 100 μm. C, Summary data plotting the average IPSC (I) receptive field centered on the EPSC (E) receptive field COM (ECOM). ON (top) and OFF (bottom) responses are analyzed separately. Scale bar: 100 μm. D, Summary data represented as polar plots of the vectors from the excitatory (center) to the inhibitory receptive fields in vDSGCs (orange, left) and nDSGCs (blue, right) for ON (solid) and OFF (dashed) responses. E, Left, Summary data showing magnitude of spatially offset inhibition (vector from E to I) for vDSGCs (orange) and nDSGCs (blue). Spatial offset predicted from the temporal offset of excitation and inhibition during preferred direction motion of a moving bar stimulus (Fig. 1) indicated in gray. Statistical significance across cell types assessed with Wilcoxon rank-sum test (*p < 0.05). Statistical significance between measured and predicted spatial offset determined by one-sided t test (all p values <0.001). Right, Summary data showing the angular deviation of spatially offset inhibition from the preferred direction of vDSGCs (orange) and nDSGCs (blue). F, Summary data representing the orientation of the EPSC’s receptive field COM relative to the orientation of the IPSC’s receptive field COM in vDSGCs (orange, top) and nDSGCs (blue, bottom) for ON (filled) and OFF (open) responses. Pearson’s correlation coefficients presented in Table 2. G, Example scatter plots of EPSC versus IPSC amplitude per pixel in vDSGCs (orange, left) and nDSGCs (blue, right) for ON (filled) and OFF (open) responses. Trend lines computed using least squares regression. Pixels with current amplitude below 5% of the maximum were excluded. Inset, Coefficient of determination (R2) for each example cell. H, Summary data of R2 values for each vDSGC (orange) and nDSGC (blue).
- Figure 3.
vDSGCs and nDSGCs display comparable distribution of synaptic inputs along their preferred-null axis. A, Summary data displaying the normalized amplitude of the inhibitory (magenta) and excitatory (green) inputs along the null-preferred axis of vDSGCs (top, n = 17 cells) and nDSGCs (bottom, n = 15 cells). ON (left) and OFF (right) responses plotted separately. B, Summary data representing the distribution of the locations of the peak inhibitory (magenta) and excitatory (green) inputs along the null-preferred axis of vDSGCs (top) and nDSGCs (bottom). C, Summary data representing the locations of the peak excitatory (E) and inhibitory (I) inputs along the null-preferred axis of vDSGCs (orange, top) and nDSGCs (blue, bottom). Statistical significance determined with a paired t test (p > 0.05).
- Figure 4.
Spatial organization of receptive fields differs from dendritic morphology. A, Example vDSGC (left) and nDSGC (right) dendritic skeletons. Orientation on the retina indicated by arrows, with preferred direction in bold. Scale bar: 100 μm. B, Summary data represented in polar plots of the vectors from the soma to the dendrites (left), the excitatory (middle) and the inhibitory (right) receptive field COM in vDSGCs (top, orange) and nDSGCs (bottom, blue). Data for ON (solid) and OFF (dashed) plotted separately. C, Summary data displaying the relationship between the orientation of dendritic morphology and the orientation of the vector from the soma to the excitatory receptive field (EPSC) COM (left) and to the inhibitory receptive field (IPSC; middle) in vDSGCs (orange) and nDSGCs (blue). Data for ON (filled circle) and OFF (open circle) plotted separately. Pearson’s correlation coefficients determined no significant correlations between dendrite angle and EPSC or IPSC locations (p > 0.05). D, Summary data comparing the relationship between dendritic area and EPSC (left) and IPSC (right) response areas within the receptive field, and the area of the dendrites for each vDSGC (orange) and nDSGC (blue). Data for ON (filled circle) and OFF (open circle) plotted separately. Statistical significance of the EPSC/dendrite and IPSC/dendrite ratio determined with one-sided t test and compared with a ratio of 1 (PSC = dendrite area). All p values <0.001.
- Figure 5.
DSGC glutamatergic receptive field is more restricted to the dendritic field. A, Left, Summary data represented as polar plots of the vectors from the soma to the excitatory glutamate receptive field COM in the presence of 100 μm Hexamethonium in vDSGCs (orange, top) and nDSGCs (blue, bottom) for ON (solid) and OFF (dashed) responses. Right, Summary data representing the deviation of the vector angle (right) from the vDSGC (orange, top) and nDSGC (blue, bottom) preferred direction. Data for ON (filled circle) and OFF (open circle) plotted separately. B, Summary data displaying the relationship between the orientation of the vector from the soma to the glutamatergic excitatory receptive field (EPSCGlu) COM, relative to the orientation of the dendritic COM in vDSGCs (orange, n = 5 cells) and nDSGCs (blue, n = 9 cells). C, Summary data comparing the relationship between dendritic area and the glutamatergic excitatory (EPSCGlu) response areas within the receptive field, and the area of the dendrites for each vDSGC (orange) and nDSGC (blue). Data for ON (filled circle) and OFF (open circle) plotted separately. Statistical significance of the EPSCGlu/dendrite ratio determined with one-sided t test and compared with a ratio of 1 (EPSCGlu = dendrite area). All p values <0.001.
Tables
ON responses OFF responses vDSGCs nDSGCs vDSGCs nDSGCs Mean SD (n) Mean SD (n) Mean SD Mean SD Dendrite asymmetry (μm) 66.67 25.50 (23) 43.08 20.51 (17) 65.83 25.40 39.98 17.32 Dendrite angle (°) 242.11 41.70 (23) 146.87 67.12 (14) 230.80 40.56 234.14 76.06 IPSC amplitude (ND; pA) 794.60 309.80 (17) 665.99 146.30 (11) 574.92 181.10 449.37 102.50 IPSC amplitude (PD; pA) 290.70 136.81 (17) 325.75 101.98 (11) 173.58 88.61 212.96 63.23 IPSC DSI 0.48 0.19 (17) 0.34 0.14 (11) 0.56 0.11 0.31 0.17 E–I timing difference (ND; ms) 36.04 67.30 (7) −53.11 92.43 (5) 136.22 76.41 39.66 144.91 E–I timing difference (PD; ms) 81.63 −262.06 (7) −257.57 134.26 (5) −292.43 476.53 −173.50 325.06 E–I spatial offset (ND; μm) 13.32 13.07 (7) 21.77 12.73 (5) 35.31 16.23 33.52 5.58 E–I spatial offset (PD; μm) 36.04 57.12 (7) 64.39 33.57 (5) 109.55 76.79 74.67 44.58 Table related to Figure 1. ND, Null Direction; PD, Preferred Direction.
ON Responses OFF Responses vDSGCs (n=17) nDSGCs (n=15) vDSGCs nDSGCs Mean SD Mean SD Mean SD Mean SD RF spatial offset magnitude (E–I; μm) 20.80 15.54 38.14 23.39 19.83 14.49 33.72 27.01 RF spatial offset deviation from PD (°) −7.53 86.59 7.90 86.95 −40.79 72.278 −4.97 70.20 R p R p R p R p EPSC angle vs IPSC angle 0.83 2.7E-05 0.67 5.0E-03 0.92 1.6E-09 0.67 6.3E-03 Table related to Figure 2.
R: Pearson’s correlation.
p: p value.
ON responses OFF responses vDSGCs (n = 20) nDSGCs (n = 18) vDSGCs nDSGCs Mean SD Mean SD Mean SD Mean SD Soma to EPSC COM vector magnitude 50.80 25.04 37.01 29.58 42.04 20.21 31.51 28.83 Soma to EPSC COM vector angle (°) 267.38 45.43 195.73 65.68 260.72 44.74 196.60 60.52 Soma to IPSC COM vector magnitude 63.00 27.20 45.05 29.69 53.89 20.79 37.50 31.94 Soma to IPSC COM vector angle (°) 264.90 41.45 295.957 74.89 259.79 42.78 279.54 75.55 EPSC area/dendrite area 1.9 0.76 2.273 1.19 1.90 0.93 2.87 1.35 IPSC area/dendrite area 1.64 0.62 2.323 1.30 1.86 0.91 3.31 1.54 R p R p R p R p EPSC angle vs dendrite angle Pearson’s correlation 0.09 0.72 0.49 0.1 0.08 0.73 0.4 0.19 IPSC angle vs dendrite angle Pearson’s correlation −0.08 0.74 0.78 *6e-4 0.24 0.31 0.39 0.17 EPSC area vs dendrite area Pearson’s correlation 0.35 0.14 0.35 0.24 0.13 0.59 0.21 0.50 IPSC area vs dendrite area Pearson’s correlation 0.13 0.60 0.13 0.62 0.11 0.66 −0.05 0.83 Table related to Figure 4.
R: correlation coefficient.
p: p value.
ON responses OFF responses vDSGCs (n = 5) nDSGCs (n = 9) vDSGCs nDSGCs Mean SD Mean SD Mean SD Mean SD Soma to EPSCGlu COM vector magnitude (μm) 58.28 22.44 41.09 24.23 52.30 30.23 39.74 19.98 Soma to EPSCGlu COM vector angle (°) 266.94 47.11 200.47 67.99 272.88 53.75 220.88 71.83 EPSCGlu area/dendrite area 1.61 0.28 1.83 1.40 1.98 0.43 2.15 1.13 R p R p R p R p EPSCGlu area vs dendrite area Pearson’s correlation 0.96 0.003 −0.14 0.7 0.88 0.02 −0.12 0.76 IPSC area vs dendrite area Pearson’s correlation 0.13 0.60 0.13 0.62 0.11 0.66 −0.05 0.83 Table related to Figure 5.
R: correlation coefficient.
p: p value.
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