hi gang

more question.

when group ICA, I was run as follows

1.# reduce the size of the time dimension using PCA
pca = ('3dpc -vmean -vnorm -reduce 20 SYHPCA_+f+ -prefix SYHPCA subject+tlrc')

2.# concatenate the reduced data from all subjects into a matrix
pcacat = ('3dTcat -session . -prefix SYHPCA_concat SYHPCA_20081127-1+tlrc SYHPCA_20081211+tlrc SYHPCA_20081218+tlrc ')

3.# reduce this matrix to N (the number of components to be estimated)
pca = ('3dpc -pcsave 10 -prefix SYHPCA_reduce_dimens SYHPCA_concat+tlrc')

question.
In Number1
when reduce Time dimension from individual subject.
what i choose the option -reduce or -pcsave?

In Number2
when concatenate the reduced data from all subjects

1 and 2, any type of concatenate data?

1. A subject [0.....50] + B subject[51...100]+c subject[101...150]=150(serial)

2. A subject[0.......50]
+
B subject[0.......50] =150(parallel)
+
C subject[0.......50]