Intro
There are several parameters in DRIFTER that need to be optimized.
Approach
Data: motion corrected data from one resting state and one task fMRI (Valsalva gives strong signal changes)
Sydney: use data in Z:\Analysis\Paul\DRIFTER\Testing
Software: DRIFTER as in the CSPM/SPM12 files (this has the correction for empty first slices). Use the batch job template on the parent page.
Analysis: 1) run drifter with the following settings, 2) create a couple of VOI for each series, 3) show timetrends of the VOI for each setting in each series
Results
| VOI | N | * Cardiac, Respiratory harmonics | ? **Overall transition probability | ? ***Markov chain transition probability | fMRI-thermode | rsfMRI | Valsalva |
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| Brainstem | raw | 0 (try up to 0.01) | 0.01 (try up to 0.05) |
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| 1 | 1,1 (default) |
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| 2 | 3,4 (as in paper) |
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| 3 | 1,4 |
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| 4 | 3,1 |
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| 5 | 2,2 |
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| 6 | 1,1 | 0.01 | 0.05 |
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| raw |  |  | |||||
| 7 | 1,1 | 0 | 0.05 |
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| 8 | 1,1 | 0.01 | 0.01 |
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| BRAINSTEM ABOVE / CORTICAL BELOW | |||||||
| Cortical | raw | 0 (try up to 0.01) | 0.01 (try up to 0.05) |
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| 1 | 1,1 (default) |
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| 2 | 3,4 (as in paper) |
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| 3 | 1,4 |
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| 4 | 3.1 |
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| 5 | 2,2 |
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| 6 | 1,1 | 0.01 | 0.05 |
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| 7 | 1,1 | 0 | 0.05 |
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| 8 | 1,1 | 0.01 | 0.01 |
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| Limbic (insula?) | raw | 0 (try up to 0.01) | 0.01 (try up to 0.05) |
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| 1 | 1,1 (default) |
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| 2 | 3,4 (as in paper) |
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| 3 | 1,4 |
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| 4 | 3,1 |
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| 5 | 2,2 |
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| 6 | 1,1 | 0.01 | 0.05 |
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| 7 | 1,1 | 0 | 0.05 |
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| 8 | 1,1 | 0.01 | 0.01 |
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| Global | raw | 0 (try up to 0.01) | 0.01 (try up to 0.05) |
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| 1 | 1,1 (default) |
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| 2 | 3,4 (as in paper) |
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| 3 | 1,4 |
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| 4 | 3,1 |
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| 5 | 2,2 |
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| 6 | 1,1 | 0.01 | 0.05 |
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| 7 | 1,1 | 0 | 0.05 |
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| 8 | 1,1 | 0.01 | 0.01 |
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* Number of periodics (default 1): The total number of periodics (fundamental + harmonics) that are estimated from the fMRI data.
** Overall transition probability (default 0): Transition probability between all steps of frequencies (i.e. the probability of a jump from e.g. 70 bpm to 80 bpm).
*** Markov chain transition probability (default 0.01): Transition probability between consecutive steps of frequencies (i.e. the probability of a jump from e.g. 70 bpm to 71 bpm).