Tutorial: Process functional NIRS data
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Authors: Thomas Vincent, Zhengchen Cai
Prerequisite:
Presentation of the experiment
- Finger tapping task: 10 stimulation blocks of 30 seconds each, with rest periods of ~30 seconds
One subject, one NIRS acquisition run of 12 minutes at 10Hz
- 4 sources and 12 detectors (+ 4 proximity channels) placed above the right motor region
- Two wavelengths: 690nm and 830nm
MRI anatomy 3T from
scanner type
Extract stimulation events
Stimulation events are stored as a box signal in channel AUX2: values above a certain threshold indicate a stimulation block.
To transform this signal into Brainstorm events, drag and drop the NIRS data "S01_Block_FO_LH_Run01" in the Brainstorm process window. Click on "Run" and select Process "Events -> Detect events above threshold".
Use the following parameters:
- set "Event name" to "MOTOR"
- select "Channel name": "AUX2"
- set "Maximum threshold" to 3
- Check "Use absolute value of signal"
Then run the process.
To view the results, right-click on "Link to raw file" under "S01_Block_FO_LH_Run01" then "NIRS -> Display time series".
The "MOTOR" event group has been created, by 10 events, each lasting 30 sec.