help > One large cluster in Seed-Voxel analysis
Nov 7, 2019  10:11 PM | Islay Davies - The University of Queensland
One large cluster in Seed-Voxel analysis
I'm running a seed-to-voxel functional connectivity analyses using the Conn toolbox on a sample of young adolescents (n = 340) acquired on a 3T Prisma (2 x 5 minute scans per participant, distortion correction prior to Conn toolbox with FSL topup).

I can't see any obvious errors with my pre-processing, denoising, and first level analyses; however, my second-level analyses results don't look correct. Basically, whichever atlas seed region I select as a source (using the default atlas in Conn) results in one large cluster of connected voxels (both positive & negative connections). The pattern of voxel connections do change depending on the seed, but it is seemingly always one large cluster containing nearly all voxels.

Any ideas where I've gone wrong? I haven't deviated too far from any of the default settings (just small changes to smoothing & the number of denoising parameters).

Kind Regards

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One large cluster in Seed-Voxel analysis
Islay Davies Nov 7, 2019
Alfonso Nieto-Castanon Nov 12, 2019
Islay Davies Nov 18, 2019