Tutorial: Process functional NIRS data

Authors: Thomas Vincent, Zhengchen Cai

Prerequisite:

• Import and visualize functional NIRS data

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.