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

History of AFNI updates  

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January 07, 2020 03:53AM
Hi AFNI wizards,

I am returning to an old dataset I previously undertook an activation analysis on to run some ROI-to-ROI FC network analyses and have a few questions (further task context below if needed):

1a. How does 3dDeconvolve determine the duration(#of TRs) of its modeled HDR function from an stim-times_AM(1) 'dmBLOCK(1)' set of stim-times in the output .xmat stimulus columns? e.g. is it a function or set number of TRs or something else to account for the long tail of the HDR?

2a. Is it possible to use a variation of 3dDevonvolve -fitts output to isolate a single condition's relevant BOLD signal from 1 or more other task conditions, or is 3dSynthesize & 3dCalc (per Gang's [afni.nimh.nih.gov]) to remove the effects/conditions of no interest from the original signal, the correct approach? In other words: can you select the best fit estimated BOLD data of a single condition out from the full model, or can you only model the effects of no interest to remove and use what is left behind?

2b. I recall reading somewhere in a help file or powerpoint that 3dSynthesize & 3dCalc script approach might be "out of date". Is there an updated process or does this merely refer to a newer python composite script?

Further context: The task is a variable-duration event-related auditory discrimination task. There are 3 randomly interleaved conditions (Strong, Weak, Silence) I would like to separate and compare the various ROI-to-ROI correlations within the network, across the group, yet between the conditions. Ex: Is FC stronger or weaker between ROI-1 & ROI-5 during strong stimuli or weak stimuli? Current 3dDeconvolve script and example stim-times file attached.

Thank you for tackling several different questions. You guys really provide a wonderful resource and support system to the community here.

~Dane



Edited 2 time(s). Last edit at 01/08/2020 12:57AM by daanderson.
Attachments:
open | download - Screen Shot 2020-01-07 at 12.42.18 AM.png (103.1 KB)
open | download - Screen Shot 2020-01-07 at 12.47.06 AM.png (19.8 KB)
Subject Author Posted

Task-Based Functional Connectivity - 3dDeconvolve & 3dSynthesis questions Attachments

daanderson January 07, 2020 03:53AM

Re: Task-Based Functional Connectivity - 3dDeconvolve & 3dSynthesis questions

daanderson January 09, 2020 01:17AM

Re: Task-Based Functional Connectivity - 3dDeconvolve & 3dSynthesis questions

gang January 13, 2020 02:01PM

Re: Task-Based Functional Connectivity - 3dDeconvolve & 3dSynthesis questions Attachments

daanderson January 15, 2020 03:54AM

Re: Task-Based Functional Connectivity - 3dDeconvolve & 3dSynthesis questions

gang January 15, 2020 05:48PM

Re: Task-Based Functional Connectivity - 3dDeconvolve & 3dSynthesis questions Attachments

daanderson February 06, 2020 04:24AM

Re: Task-Based Functional Connectivity - 3dDeconvolve & 3dSynthesis questions

gang February 07, 2020 02:23PM