Fig. 6.

Group-level parameters at individual sensors. (a) The least-square estimate of β_G in Eq. (10), (b) the standard deviation of $\widehat{{\beta }_G}$ in Eq. (11), (c) the corresponding T-values, and (d) the channel positions on the surface of a volume rendered brain. The blue plots indicate the group level parameters obtained from conventional procedures by analysing data from each channel separately. The red plots indicate the group level parameters obtained from the proposed method by analysing data from spatially interpolated contrast images. The implied spatial smoothing in the 2D and 3D SPMs significantly reduced standard deviation of group-level parameters over subjects ($\widehat{\text{std}}[{\hat{\beta }}_G]$), which led to increases in T-values at individual sensors and nearby voxels in 2D and 3D SPMs. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)