Our Protocol

Our current protocol involves the following order of tasks:

Prior to the rest period, we perform practice tasks for each task, including the handgrip max. If you analyze the handgrip max, you can use that part to determine each participant’s maximum grip strength. The rest of the practice tasks, you can ignore. Sometimes, we start a task and there is either an error or the participant is unable to do the task without further explanation, so we cancel the attempt and restart. Those parts, please also ignore.

Official user manual

Link: User manual

Analysis

We open a sample data set (.nir file):

The software will ask if you also want to open the corresponding marker file. Click “Load”.

 In the file opened, you will now see

1. pink lines: channels with one frequency

2. purple lines: channels with another frequency

3. green line on the bottom: ambient lighting

4. numbered markers (different number for each type of event) on top; vertical line shows marker timing across all 48 channels

Right-click → Optode layout view: here you can view your data in a 2x8 layout.

If you have too many markers, it will be difficult to see individual events on the signal.

In order to focus just on the signal, right-click → toggle marker visibility

Now you see the signal only:

You can see clearly here that optode 8 shows a saturated signal for both wavelengths:

We cannot use this signal and therefore have to exclude it from analysis.

Double-click on optode 8, then right-click → evaluate → reject

Now the signal of the optode is no longer shown.

This does not delete the data, it only excludes the data from the analysis.

If you want to undo this step, you go right-click → evaluate → accept.

You can also remove parts of the signal that show saturation or other signal contamination.

For example, you can right-click → evaluate → Define exclude period either “For all channels” or below “only for channels on display” AND THEN>>?>

You can also change your display settings for that by going

Right-click → Display settings

DATA: select by wavelength as shown here or select individual optodes under “Select by optode” or individual channels (1-48)

DATA RANGE: select your desired time window

TYPE: raw data or already filtered data

MARKER: check box “Show markers” and then decide whether you want to view just the defined time range or only specific markers (e.g. all markers for breath hold onset).

TIME: select whether you want to view the entire data, a time range or blocks of time