Fig. 4.

Linear ramp and circular signals $\mu \left(\mathit{s}\right)$.

Fig. 4a: Signal 1. A linear ramp signal that increases from magnitude of 1–3 in the x-direction.

Fig. 4b: Signal 2. A circular signal with magnitude of 3 and radius of 30, centred within the region and convolved with a 3 voxel FWHM Gaussian kernel.