Fig. 2: Distribution of the sill and effective distance of variograms across the cortex. | Nature Communications

Fig. 2: Distribution of the sill and effective distance of variograms across the cortex.

From: Variation in spatial dependencies across the cortical mantle discriminates the functional behaviour of primary and association cortex

Fig. 2: Distribution of the sill and effective distance of variograms across the cortex.

A Variograms can be formally described through comparison of the observed rate of change between similarity in brain activity and distance with different mathematical growth functions. We observe that the whole-brain variogram has most similarity to an exponential function. B Variograms can be characterised by two numbers, the partial sill (the height of the curve at 95% of its asymptote) and the effective range (the distance of the sill). C Both the sill and the range of the whole brain variogram show reasonable similarity when measured within the same individual in two scans on the same day (>0.73). D The regional distribution of the range (the distance of the sill) and (E) the sill (the height of the variogram at 95% of its asymptote) across the vertices of the human cortex. It can be seen that the sill varies from 0.25 and 0.5 across the cortex and that in some regions the range can be as long as 15 cm. The relationship between the F distribution of the principal gradient of intrinsic connectivity and (G) variograms at each vertex (as described by each vertex’s partial sill and effective distance). H Spin permutation tests to assess the significance of the correlation between the principal gradient and theoretical variogram parameters (the range and the sill). The true values are depicted by the dashed lines and the histogram displays the distribution of correlations from the permuted maps.

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