On Tue, 24 Jun 2008 14:11:03 +1000, Nicholas Bradfield
<[log in to unmask]> wrote:
>dear all,
>does anyone know where i can obtain an extension/toolbox for matlab that
will allow me to correlate an roi time series with every other voxel and
output a summary image that will contain the correlation coefficients at
each voxel so that i can enter it into a second level analysis?
>any help would be greatly appreciated.
>nick
In addition to what Volkmar said, I think you need to consider the
following points:
(1) Filtering. There's a lot of low-frequency noise in EPI time series,
and there's a good chance that that noise will introduce a large amount of
spurious correlation.
(2) Intensity normalization. For one subject, you don't have to worry
about anything. But for many subjects combined in a random effects
analysis, you have to decide how and whether to normalize the "seed" time
series.
>--
>Nicholas Bradfield BBNSc (Hons)
>Provisional Psychologist
>Candidate for Doctorate of Clinical Neuropsychology
>Department of Medicine (Neurosciences)
>Monash Medical Centre
>5th floor, E Block
>246 Clayton Road, Clayton 3168
>Victoria, Australia
>telephone:+61 3 9594 5543
>mobile: 0419 386 255
>facsimile: +61 3 9594 6495
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