Dominance of Attention Focus and Its Electroencephalogram Activity in Standing Postural Control in Healthy Young Adults

Figures

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  Figure 1. At first, the participants performed the task in the “no attentional instruction” condition without attentional focus. The participants were randomly divided into two groups. One group performed the IF condition followed by the EF condition, and the other group performed the EF condition followed by the IF condition. The participants performed a washout task with no attention focus in between the attention-focused tasks. Attention was focused on the inside and outside of the body in the IF and EF conditions, respectively. IF: internal focus; EF: external focus.

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  Figure 2. The participants performed a standing postural control task by standing on foam rubber placed on a stabilometer with both arms folded in front of their chest. The participants wore an electroencephalogram on their heads. A monitor was placed in front of each participant, which displayed only the center of the pressure cursor at that time.

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  Figure 3. The IPS was determined for all participants. The center of pressure sway, for 10 s, was measured for each participant in the center and in different postures including tilted front, back, right, and left maximally. The gray area indicates the area of postural sway on each position. The shaded area indicates the area of stability limit. IPS: index of postural stability.

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  Figure 4. (a) The scatter plot depicts the IPS in the IF and EF conditions. Participants whose IPS in the EF condition was higher than that in the IF condition were classified as the IF-dominant group. Those whose IPS in the EF condition was higher than that in the IF condition were classified as the EF-dominant group. (b) The EF-dominant group included participants with a positive difference in IPS. By contrast, participants with a negative difference of IPS were included in the IF-dominant group. EF: external focus; IF: internal focus; IPS: index of postural stability.

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  Figure 5. Comparison of theta activity of each group in IF and EF conditions. The red region represents the area where the theta activity was significantly higher in the IF-dominant group than the EF-dominant group. The blue region shows the area where the theta activity is significantly higher in the EF-dominant group than the IF-dominant group. The color bar represents the voxel log F-ratio values. (a) Comparison of the theta activity between the IF-dominant and EF-dominant groups in the IF condition. In the IF condition, the activity of the left parietal lobe (BA40) was significantly higher in the IF-dominant group than in the EF-dominant group (p < 0.05). (b) Comparison of the theta activity between the IF-dominant and EF-dominant groups in the EF condition. In the EF condition, the activity of the left frontal lobe (BA32) was significantly higher in the EF-dominant group than in the IF-dominant group (p < 0.05). EF: external focus; IF: internal focus.