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
December 17, 2008 12:49PM
> wasn't it the case that if the overall trial length was a multiple of the TR, the
> bold response was always sampled in the same points, leading to a poor
> estimation of the HRF?

It is the jittering of the inter-stimulus intervals that would help you sample different phases of the hemodynamic response curve. In other words, compared to a fixed inter-stimulus interval, your regressors would be less correlated with each other, and you'd gain higher statistical power (more successfully detect what you are looking for). The range of jitter values depends on overall consideration of multiple factor such as total scanning time, number of trials per condition, etc.

Gang
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Subject Author Posted

jitter advice

Elisa December 16, 2008 01:49PM

Re: jitter advice

Gang Chen December 17, 2008 12:49PM