Enhancing the Detection of BOLD Signal in fMRI by Reducing the Partial Volume Effect

Figure 3

A synthetic data set (128 × 128) simulating fMRI activations of various sizes. Single-voxel “activations,” with signal changes of 1%, 2.5%, and 5% were placed at rows A, B, and C, respectively. The 2D coordinates of activation at column 1 are odd, odd; column 2 are even, odd; column 3 are odd, even; and column 4 are even, even, respectively. Rows D to F show multivoxel “activations”: the same single-voxel “activations” in rows A to C were duplicated, together with 8 surrounding “activated” voxels added to these single-voxel “activations.” The signal of the surrounding voxels is half of that in the central voxel.