AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

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Gang Chen
November 23, 2009 11:13AM
Generally speaking more trials per condition would render more precise (reliable or robust) estimate of the BOLD response magnitude. However, it's hard to give a magic number (the minimum number of trials) for achieving a desirable statistical power because that depends on experiment type (block or event-related), tasks/conditions, brain regions, etc..

Instead of adopting a dichotomous decision about the threshold number of trials, it would make sense to run group analysis, if this is your ultimate goal, based on the precision/reliability/robustness of each subject's beta estimate, which is what 3dMEMA was created for:

[afni.nimh.nih.gov]

Gang
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Subject Author Posted

number of trials

Elisa November 23, 2009 10:02AM

Re: number of trials

Gang Chen November 23, 2009 11:13AM

Re: number of trials

Elisa November 24, 2009 09:25AM

Re: number of trials

Gang Chen November 24, 2009 02:58PM

Re: number of trials

Tom November 24, 2009 05:20PM

Re: number of trials

Colm Connolly November 26, 2009 05:14PM