I wish to know what fMRI data looks like after preprocessing.
My understanding is that fMRI is MRI in time dimension that is we have repeated scans of brain volume. A voxel is a unit if measurement in fMRI because BOLD signal is measured on a typical voxel in different regions of the brain using gradient of the High frequency signal.
For example if we have fMRI scans say of D ADHD patients, V voxels and T time points in a fMRI study then how the fMRI data after pre-processing would be arranged in a matrix form.
If we assume that it is organized in D x V x T then we have a 3D scan of each brain on a time dimension. Since each 3D scan consists of voxels in the brain, and voxels are cubes that have 6 values around them, then where are those 6 values?
If a voxel is a cube, does it have a single value, or 6 potentially different values on each face? I know voxels have coordinates like that in the MNI coordinate system.