Introduction
In order to achieve precise and trustworthy data, proper setup and calibration of the NIRScout is key. The setup process involves fitting the participant with headgear to hold the FNIRS optodes. During this process, hair sweeping is required to create an optimal optode-scalp placement. Because of the vast difference in hair length and thickness between participants, ultrasound gel may be required for use on participants with thick and (or) long hair. Calibration of the NIRScout system shows how well the optodes are placed.
Warming up the NIRScout and Preparation
30 minutes prior to the arrival of the participant switch the NIRS system on to allow for warm up time. Open NIRx Star.
Welcome the participant and ask if they would have a seat in the EEG collection room. Begin by explaining the procedure, what we will be doing, and what the participant will be doing during the testing as well as the time requirement.
NOTE: determine whether their hair will need gel: ideal=shot-medium fine hair. Thick longer hair makes the sweeping process more difficult and may require ultrasound gel from the beginning
Placing the NIRScap and Optodes
Consult this video for step by step instructions for how to apply the NIRScap.
Selecting a Montage
Click “configure hardware” located in the top left hand corner of the window. Within this page select the desired montage from the center dropdown window. For the purposes of this tutorial, “motor_8x4” is selected. Once the montage has been selected, close the window.
Calibrating the NIRScout
Once the cap and over-cap are secure, turn off the lights and close the door and click “calibrate” under “Main Functions” to calibrate the optodes. After the system is calibrated, click “details” under “Main functions” this will bring up the quality scale window, where you are able to view the topographical layout and operational values of the optodes. The numbers within the boxes describe the sensors and detectors. For instance, if a box read “3-2”, this would indicate sensor 3 and detector 2 (sensor is listed first, detector second) Within this screen, toggle between the tabs at the top of the screen to view how well the optodes are placed. Boxes displayed in green are optimal, and values should be compared to the quality scale bar on the right end of the window.
Visualizing data and adjusting skin blood flow levels
Following the selection of the montage, adjust the skin blood flow waves by sliding “Scale Factor of each channel [mmol/l]” and “LP Filter Cutoff (Hz)” until the waves are more linear, as shown in the image.
Beginning the Recording
Before beginning the recording, click, “configure hardware” and within the Hardware configuration window, click “Preview Display” This will open up a GUI that allows the visualization of bloodflow by hemisphere. Once the recording begins you will not be able to open this GUI. After the recording has begun, click “Prepare display” within the GUI window to get a real-time interpretation of blood The recording process for NIRx NIRStar can be confusing. To begin recording, click “Preview” this toggles the recording on, but the file will not be saved until the “record” button is clicked. Once “preview” has been selected, a Subject Demographic window will be brought up. Fill in the information as desired and click “Done”.
When ready, click record. Run the baseline as long as desired before adding events. In a motor test, the first marker can be added by pressing “F1” while the second marker is added by pressing “F2”. This is visualized by a vertical black line in the data visualization window. In dot probe tasks, the computer will add events automatically. After the test has ended, click “stop” to end the recording.
Removing gear and Thanking the Participant
Thank the participant for their time and help them out of the headgear.
