Yes. Many artifacts can lead to such striping, but motion
is liekly the main culprit.

The 3dTshift operation is supposed to synchronize signals,
which should increase correlations (due to BOLD, motion,
etc), but that depends on a given signal being spatially
consistent. In some ways motion is consistent, in some
ways not. It is the unpredictability of motion effects
that makes it so difficult to handle in FMRI data.

Also, Fourier interpolation could hurt here (which is why
we do not tend to use it). It can cause spikes to ring
through the data, which might increase correlations.

It is indeed hard to conclude much from this. As with
most options in FMRI, if they were simple, there would
be no questions, and they would not even be options...

- rick