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Author: Paul Hamilton (---.Stanford.EDU)
Date: 01-27-09 17:19
Dear AFNI Community,
We're interested in estimating condition-specific IRF durations in an event-related paradigm. We've tried/conceived of two ways to do this:
1. Run 3dTstat with the -duration option on IRFs rendered from 3dDeconvolve with the -iresp option. This works okay.
2. We're considering - but have not yet tried - the new duration modulation feature in 3dDeconvolve. Perhaps something like...
3dDeconvolve -input 3dplustime+orig -num_stimts 2 \
-stim_times_AM 1 cond1.1D 'dmBLOCK' -stim_label 1 'cond1' \
-stim_times_AM 2 cond2.1D 'dmBLOCK' -stim_label 2 'cond2' \
-gltsym 'SYM: +cond1 -cond2' -glt_label 1 'cond1 - cond2' \
cond1.1D = 4:12 18:12 30:12 ...
cond2.1D = 12:12 40:12 56:12 ...
In this case, we've set the "modulating parameter" to a constant value of 12 since we're not interested in any condition-by-behavioral measure effects, only in condition effects on average IRF duration. Another, perhaps ridiculous, way to say what we're after is that we're looking for a way to rotate 3dDeconvolve 90 degrees and to estimate extent on the time dimension as opposed to the signal intensity dimension.
Please feel free to respond only with a ":-(" if I've misunderstood the basic intent the duration modulation option.
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Estimating IRF duration |
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Paul Hamilton |
01-27-09 17:19 |
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Bob Cox |
01-28-09 10:24 |
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Paul Hamilton |
01-28-09 21:26 |
