Preserving Early Neurovascular Responses: The Effect of tACS on the Hemodynamics in Stressed Individuals
This study examines the impact of transcranial alternating current stimulation (tACS) on the initial dip; an initial decrease in oxygenated hemoglobin (HbO) that arises during early neural activation, in individuals experiencing mental stress. Using functional near-infrared spectroscopy (fNIRS), we...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IEEE
2025-01-01
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| Series: | IEEE Transactions on Neural Systems and Rehabilitation Engineering |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/11026101/ |
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| Summary: | This study examines the impact of transcranial alternating current stimulation (tACS) on the initial dip; an initial decrease in oxygenated hemoglobin (HbO) that arises during early neural activation, in individuals experiencing mental stress. Using functional near-infrared spectroscopy (fNIRS), we examined the effects of tACS on the initial dip and prefrontal activation in 40 participants subjected to mental stress induced by the Stroop Color-Word Task. The results indicate that tACS maintains the amplitude of the initial dip following stimulation, showing no significant change in amplitude (<inline-formula> <tex-math notation="LaTeX">${p} \gt 0.05$ </tex-math></inline-formula>). In contrast, the sham group demonstrated a significant increase in initial dip amplitude (<inline-formula> <tex-math notation="LaTeX">${p} \lt 0.05$ </tex-math></inline-formula>). This indicates that tACS improves neural efficiency by sustaining initial metabolic responses. Moreover, tACS-induced changes in functional connectivity demonstrated a reorganization of brain activity, characterized by a significant reduction in task-based connectivity (<inline-formula> <tex-math notation="LaTeX">${p} \lt 0.001$ </tex-math></inline-formula>), which may enhance cognitive performance. Behavioral and physiological measures indicated a 15% reduction in salivary alpha amylase levels and a 20% improvement in NASA Task Load Index scores, thereby supporting the stress-mitigating effects of tACS. Machine learning classifiers demonstrated significant accuracy in differentiating brain states, achieving classification accuracies as high as 92.6% for the initial dip phase utilizing convolutional neural network. The findings underscore the therapeutic potential of tACS in modulating early neural responses to stress, providing new insights into non-invasive modulation for cognitive performance and mental well-being. |
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| ISSN: | 1534-4320 1558-0210 |