Hi,
Monkeys have far more muscles on the skull than humans. With awake
animals it is quiet usual to detect 'activations' in the muscles or the
basis of the eyes. This usually is task related motion (swallowing,
saccades) and could strongly confound the data, even though these
'activations' could make sense. Since you are just interested in brain
activity I would recommended to do the statistics only for the brain.
Therefore brain extraction prior statistical analysis would be good.
Is there anything in your paradigm, that could cause correlated muscle
activity (i.e. as reflex)?
good luck,
wolf
neeru K wrote:
> Dear SPMers!
> I am doing fMRI of anesthetized monkeys and I am getting BOLD
> acitvations (analyzed in SPM5) outside the brain (in addition to
> inside the brain), especially in the muscles overlying the skull and
> orbits of eyes and it seems consistent.
> I thought it could be a problem with coregistration but it persistes
> even when I overlay the contrasts onto the mean EPI image....
> Has anybody faced a similar problem in human data and if so what is
> the solution...
> Could there be also a problem in acquisition of the data
>
> Thanks
>
> --
> Niranjan Kambi
> SRF, Neeraj Lab,
> National Brain Research Centre
> Manesar, Gurgaon-122050
> Haryana, INDIA
> Ph:+919818654846
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