I performed flexible factorial design(2X2 ANOVA) for group analysis, but one of the result (interaction effect) showed strange.

Particularly one of the largest activation area was ventricle. Is this possible, even if the preprocessing is well done?

I did all preprocessing process including segmentation.

I wonder if this should just be an artifact, or should I understand that the preceding process is wrong?

Waiting for your reply… thank you.

Beginner K.