Effects of acute high‐altitude exposure on working memory: A functional near‐infrared spectroscopy study

Figures

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  FIGURE 1. Configuration and cortical position of the fNIRS probe: (a) configuration of the fNIRS probe. Red circles represent light sources, blue squares represent detectors, and green lines represent the nearest source‐detector pairs (channels) to measure the brain activities. (b) Coregistered positions of the optodes on a standard brain atlas. The anatomical position of each channel on the brain atlas is reported in detail in Table 1. The channel involved in DLPCF: channels 1, 2, 3, and 5 are the left DLPFC and channels 15, 17, 18, and 20 are the right DLPFC

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  FIGURE 2. Experimental of digital span. A black symbol “+” reminder the task to begin immediately for 1000 ms. Six numbers from zero to nine are then randomly displayed on the screen for 1000 milliseconds each, followed by a blank screen for 10 s; finally, a series of numbers appeared on the screen, and the subjects were asked to complete the sorting within 10 s (in positive/reverse order), rest 20 s before next task. The backward task (reverse order) is more difficult than forward task (positive order)

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  FIGURE 3. Mean task‐evoked [HbO] and[HbR] concentration of DLPFC in the group during both in the normxic and hypobaric hypoxia conditions: (A) mean [HbO] and[HbR] concentration on forward and back digital task of (a) left DLPFC and (b) right DLPFC during normoxic conditions; (B) mean [HbO] and[HbR] concentration on forward and back digital task of (a) left DLPFC and (b) right DLPFC during hypobaric hypoxia condition; (C) mean [HbO] and[HbR] concentration on forward digital task of (a) left DLPFC and (b) right DLPFC during both normoxic and hypobaric hypoxia conditions; (D) mean [HbO] and[HbR] concentration on back digital task of (a) left DLPFC and (b) right DLPFC during both normoxic and hypobaric hypoxia conditions. The pink line on the horizontal is encoding, the brown line is maintenance, the yellow line is retrieval, and the black line is rest

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  FIGURE 4. The images of the task‐evoked prefrontal activations in the each subject during both in the normal and hypobaric hypoxia conditions. The rows 1 through 5: brain regions activation evoked by the digit span task in each subject