¥ It is possible to find voxels where
pre-whitening of different types (AR-only or MA-only or ARMA) is ÒoptimalÓ
H And voxels where pre-whitening makes
little difference
¥ For many (most?)
voxels, the pre-whitening details donÕt make a lot of difference in the statistics
H As long as something is done that
is about right
H e.g.,
Using fixed AR(1) or MA(1) single parameter method was still OK-ish for single subject maps
oA few more extraneous small blobs
oBut fewer than pure OLSQ solution statistics
¥ Map of r1=correlation
at neighboring TRs,
¥ as output by REML and ARMA(1,1)
fit
H Same slice as previous slides (NIH 3 T data)
H In general, cortical gray matter shows
more
H
correlation, but this result is not universal
H
H