We did an experiment in which we compared 2 conditions (FT a&b) in 4
separate runs (a-b-a-b). For each run we used a block design finger
tapping versus rest (30sec FT(a or b) - 30s Rest). TR = 3sec.
In each run we collected 100 scans (50 rest and 50 FT a or b). So for
each subject there is a total of 100 scans per condition.
When we do group analysis we see no activation when we compare the 2
conditions on first level. On the contrary we do see activation with
the second level group analysis.
On the other hand, when we do a first level analysis for each subject
we see brain activations, but none of these activations seem to
correspond with the activation we find on second level group analysis.
Is there a reasonable explanation for this? And can we trust the
activation we see on second level analysis, activation which can be
explained based on literature.
Thanks,
Koen Matthys
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