Dear John,
> Hello all, I adquired 80 volumes in blocks using clustered adquisition: 3 seconds of silence and 3 seconds of MRI noise. During the silence period I present the stimuli. How can I process the data? Exists any additional consideration in the processing?
There are a number of ways you can approach this; I suggest searching the archives (try the keyword "sparse"). With a TR of 6 seconds, as you have, your best bet is probably to use a canonical HRF, but to adjust the microtime onset (SPM.T0) and microtime resolution (SPM.T) appropriately. See, for example:
https://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=SPM;27ab2eb2.1010
(Also, in relation to Donald's point, I wouldn't do slice-timing correction if sparse sampling is used—because of the long TR, the interpolation is unlikely to be accurate.)
Hope this helps,
Jonathan
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