Fig. 6: The vLGN input enhances surround suppression in SC. | Nature Communications

Fig. 6: The vLGN input enhances surround suppression in SC.

From: Enhancement and contextual modulation of visuospatial processing by thalamocollicular projections from ventral lateral geniculate nucleus

Fig. 6

a Schematic of calculating surround suppression index (SSI) from the size tuning curve. b SSI in LED-ON vs. LED-OFF conditions for photo-inhibition of vLGN VGAT+ neurons. c Changes of SSI induced by the photo-inhibition. n = 56 neurons, ****p < 0.0001, two-tailed Wilcoxon matched-pairs signed rank test. Bar represents s.e.m. d, e Similar to (b, c) but for photo-activation of vLGN VGAT+ axons in SC. n = 64 neurons, ****p < 0.0001, two-tailed Wilcoxon matched-pairs signed rank test. f Schematic of the difference-of-Gaussian (DoG) model. A SC neuron integrates spatially sharp excitatory input (green curve) from retina and visual cortex and spatially broad inhibitory input (red curve) from vLGN. Black curve (right) represents the linearly summed input. g Suppression of vLGN input. Left, spatial tuning curves of excitation (green), inhibition (red) and the integrated response (lower) before (gray) and after (orange) photo-inhibition of vLGN input. Red arrow indicates a reduction of inhibition. Right, simulated size tuning of the SC neuron before (gray) vs. after (dashed orange; solid orange represents tuning curve after normalization) suppressing the inhibitory input. Vertical colored bars indicate the optimal size. Arrow marks the direction of the shift of optimal size. h Similar to (g) but for photo-activation (i.e., strengthening) of vLGN input (blue). i Effects of manipulating the broadness of vLGN input on SC size tuning. Gray, orange and blue represent tuning curves in the control, photo-inhibition and photo-activation conditions, respectively. Colored bars on top indicate the optimal size in different conditions. Inset, spatial tuning of excitation (green) and inhibition (red). j Effects of manipulating the spatial broadness of vLGN input on SSI of SC neurons (left) and on the change of SSI induced by photo-inhibition (orange) or photo-activation (blue) of vLGN input (right). The three black dots mark the conditions for the three plots in (i). k Similar to (j) but for effects on the optimal size. Data are presented as mean ± s.e.m. in (c, e). Source data are provided as a Source Data file.

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