Examination of the Prefrontal Cortex Hemodynamic Responses to the Fist-Edge-Palm Task in Naïve Subjects Using Functional Near-Infrared Spectroscopy

Figures

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  FIGURE 1. Photographs indicating the postures of the right hand (A) and both arms (B) in the Fist-Edge-Palm (FEP) task, and postures of both arms in the palm tapping (PT) task (C). (Aa–c) Photographs showing vertical “fist” (a), vertical palm (i.e., “edge”) (b), and horizontal “palm” (c) on a table in the FEP task. (Ba–c) Photographs showing both arms corresponding to (Aa–c). (Ca–c) Palm tapping on a table in the PT task.

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  FIGURE 2. Arrangement of the near-infrared spectroscopy (NIRS) source and detector probes (A) and channels (B), and an example of the distribution of NIRS channels in one subject (C). The brain regions surrounded by the red lines indicate the three ROIs: the frontal pole (FP) area, and right (R-dlPFC), and left (L-dlPFC) dlPFC. In panel (C), only three short channels (green circles) are shown. The remaining two short channels are located posteriorly behind the outer edge of the cerebral cortex and are invisible.

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  FIGURE 3. Relationships among the psycho-behavioral data in the Fist-Edge-Palm (FEP) task, Wisconsin Card Sorting Test (WCST), and Schizotypal Personality Scale (STA) total scores. (A) Number of errors across the three trials in the FEP task. **Significant difference from the second and third trials (p < 0.01). (B) Relationship between the changes in errors between the first and second trials in the FEP task and Milner type perseveration errors in the WCST. Each dot indicates each subject; the total number of dots is 19, but some dots overlap. (C) Relationship between changes in the errors between the first and second trials in the FEP task and total scores in the STA.

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  FIGURE 4. Examples of the hemodynamic responses in the prefrontal cortex (PFC) across the three trials in the Fist-Edge-Palm (FEP; A) and palm tapping (PT; B) tasks. Topographical maps indicate the effect sizes of the hemodynamic (Oxy-Hb) responses during the tasks. FEP1-3, first (Aa), second (Ab), and third (Ac) trials in the FEP task; PT1-3, first (Ba), second (Bb), and third (Bc) trials in the PT task. Yellow dots on the head indicate the whole component channels. ch, NIRS channel number. Insets indicate temporal changes in the hemodynamic activity in ch 48 during the FEP and PT tasks. Red, blue, and green lines in insets indicate Oxy-Hb, Deoxy-Hb, and Total-Hb, respectively.

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  FIGURE 5. Comparison of the hemodynamic responses (effect sizes of Oxy-Hb responses) in the prefrontal cortex (PFC) between the Fist-Edge-Palm (FEP) and palm tapping (PT) tasks. ****p < 0.0001.

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  FIGURE 6. Relationships between the prefrontal cortex (PFC) hemodynamic responses in the Fist-Edge-Palm (FEP) task and psycho-behavioral data. (A) Relationship between the changes in the PFC hemodynamic responses (effect sizes) between the first and second trials and error reduction between the first and second trials in the FEP task. (B) Relationship between the changes in the PFC hemodynamic responses (effect sizes) between the first and second trials of the FEP task and Milner type perseveration errors in the Wisconsin Card Sorting Test (WCST).