> I have been looking in the SPM archives trying to explain some
> mysterious CSF activations in the ventricles. I've noticed that people
> do run into these some times. I've ruled out bad normalizations and
> paradigm-corelated movement. It happens to enough subjects in this
> paradigm to make me think that something is really going on.
>
> Can someone point me to papers (I'm still searching) that would
> explore this issue or report those ventricular activations, or share
> their ventricular experiences? I understand that the choroid plexus is
> a big source of variance and that CSF pressure is modulated by
> respiration and heart beat ..... but I'd like to get a better sense
> for why this happens before I mask out the ventricles and go on with my
> life.
Are you excluding the first few scans from your fMRI series? In the
first few scans, there is a different contrast between the various
tissues. This takes a little bit of time to reach an equilibrium.
Best regards,
-John
--
Dr John Ashburner.
Functional Imaging Lab., 12 Queen Square, London WC1N 3BG, UK.
tel: +44 (0)20 78337491 or +44 (0)20 78373611 x4381
fax: +44 (0)20 78131420 http://www.fil.ion.ucl.ac.uk/~john
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