Coherence NxN source file errors

Hey just wondering if it is possible to run Connectivity-> Coherence NxN on source files? Every time I try to I either get an out of memory error or input signals may be too short error.

Thanks,
killa7

Hello

If you have a source file with 15000 vertices and try to compute the coherence NxN for this file (sampling rate = 1000Hz), the size of the output file will be:
15000 * 15000 * 500 * 8 / 1024^3 = 838 Gb!
This cannot fit in the memory of any computer…

If you select all the scouts of an atlas, with the option “Scout function: After”, it will first compute this 15000x15000 connectivity matrix and then group by scouts.
You can instead select a few scouts and/or use the option “Before”.

For the error indicating that the input recordings are too short, this is not related with the number of signals you are testing.
You can find the code computing the minimum number of recommended time points in function brainstorm3/toolbox/connectivity/bst_cohn.m, line 109-127.

Cheers,
Francois

A post was merged into an existing topic: Scout Atlas for Brainstorm and connectivity