PMC7456944_01
PMC7456944_02
Illustration of the N-back working memory task. In the 0-back condition, the target letter is "X" (indicated with underline). In the 1- and 2-back conditions, the target letter is the same as the letter from 1- or 2-steps before in a given sequence, respectively. Each condition was repeated eight times with the rest period in between conditions.
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F1
The details of task design are illustrated in Figure 1.
Position of fNIRS sensor on the forehead. Each channel represents the source-detector pair measuring the changes in oxy-hemoglobin and deoxy-hemoglobin from prefrontal cortex regions.
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F2
Devices, LLC) with the middle of sensor matching on the fPz location based on the 10-20 system. Detectors to the left and the right were located on the AF7 and AF8 locations, respectively, while sources from left and right were covering the regions of F5, AF3, AF4, and F6, respectively (Figure 2). Channels 4, 6, 8, 10, 12, and 14, which covered the bilateral prefrontal region, were included in analysis (Figure 2).