On this note (perhaps...) I have also seen people ask how to discard the first few images in fMRI runs. Is this good practice - I work mostly with rs data. Should I discard the first 2-4 of a ~256 image run across the board?
Thanks much,
Nina
On Fri, 28 Mar 2014, John Ashburner wrote:
> Not sure. If it was task-correlated, I would generally expect a rim of signal at the edge of the brain. This
> seems to be in the ventricles, so my first thought was that it could be related to the slightly different
> contrast seen in the first couple of scans in an fMRI run (before things have equilibrated). The design matrix
> and contrast vector don't seem to support this idea though, as the events of interest are not right at the start
> of the runs. I'm a bit stumped.
> Best regards,
> -John
>
>
>
> On 28 March 2014 19:43, Colin Hawco <[log in to unmask]> wrote:
> Best guess: task correlated motion?
>
>
> On 28 March 2014 04:51, Andy Yeung <[log in to unmask]> wrote:
> Dear all,
> I would like to know if I have pre-processed wrongly or any reason for the strange activation in
> lateral ventricles as attached. From realignment, seems there was no abrupt and severe head
> movements...
>
> Thanks,
> Andy
>
>
>
>
>
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