Number of components depends on a large number of things including length of run, TR, voxel resolution, brain state, and amount of motion. In general as scans improve/have more information in them you will get more total components. Also as you have more motion in a scan, this will increase the number of bad components. As successful ICA run separates good and bad components cleanly so that the bad components can be regressed out without removing neural signal. In general this is easier to do in better quality data and there is no ratio of good to bad that is expected.
Matt. From: <[email protected]<mailto:[email protected]>> on behalf of "Theis, Nicholas" <[email protected]<mailto:[email protected]>> Date: Wednesday, August 1, 2018 at 12:05 PM To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Subject: [HCP-Users] Number of "good" vs "bad" independent components classified by FIX Dear HCP community, While the number of "good" and "bad" components certainly depends on the fMRI paradigm, such as a specific task versus a resting state scan, as well as the quality of the scan and similarity to training data (I'm using HCP_hp2000.RData), is there in general an expected value for the number of "good" components in a successful ICA? For instance, on a rsfMRI scan should MELODIC produce, say, 100 components, 10 of which are classified as "good" by FIX, 80 as "bad" and 10 as "unknown"? Or is the breakdown usually closer to 50% "good", 50% "bad" - in your experience? Or is there really no heuristic as far as a proportion of good/bad/unknown components in a successful ICA of fMRI data? Thanks for your time, Nick Theis _______________________________________________ HCP-Users mailing list [email protected]<mailto:[email protected]> http://lists.humanconnectome.org/mailman/listinfo/hcp-users ________________________________ The materials in this message are private and may contain Protected Healthcare Information or other information of a sensitive nature. If you are not the intended recipient, be advised that any unauthorized use, disclosure, copying or the taking of any action in reliance on the contents of this information is strictly prohibited. If you have received this email in error, please immediately notify the sender via telephone or return mail. _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
