Extended Data Figure 3. Direction selectivity of parenchymal vessels and of local spiking and synaptic activity.

a, Population distributions of the direction index of calcium (green, n = 19 windows in 8 cats), glutamate (blue, n = 37 windows in 5 cats) and vessel dilation (red, n = 79 vessels in 18 cats) responses. All data were obtained from cat visual cortex and neural responses were pooled over 400-μm-diameter windows. The directionality index (DI) of spiking activity was greater than the DI of synaptic responses (P < 0.01; Mann-Whitney test) and the DI of vessel dilation (P < 0.0005; Mann-Whitney test). The DI of synaptic activity was not different from the DI of vessel dilation (P = 0.70; Mann-Whitney test). Solid bars are medians and boxes show the inter-quartile range. b, For each vessel that had a corresponding 400-μm-diameter window of calcium or glutamate activity, the vessel direction index is plotted against the corresponding neural direction index. There was no significant correlation for calcium (R = 0.2; P = 0.43; n = 19 pairs) or glutamate (R = 0.2; P = 0.23; n = 37 pairs).