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Park, Yeseung; Yoon, Euisuk; Park, Jieun; Kim, Jun Sung; Han, Ji Won; Bae, Jong Bin; Kim, Sang-Su; Kim, Do-Won; Woo, Se Joon; Park, Jaehyeok; Lee, Wheesung; Yoo, Seunghyup; Kim, Ki Woong
White matter microstructural integrity as a key to effective propagation of gamma entrainment in humans Journal Article
In: GeroScience, vol. 47, no. 1, pp. 1019–1037, 2025, ISSN: 2509-2723.
@article{Park2024,
title = {White matter microstructural integrity as a key to effective propagation of gamma entrainment in humans},
author = {Yeseung Park and Euisuk Yoon and Jieun Park and Jun Sung Kim and Ji Won Han and Jong Bin Bae and Sang-Su Kim and Do-Won Kim and Se Joon Woo and Jaehyeok Park and Wheesung Lee and Seunghyup Yoo and Ki Woong Kim},
doi = {10.1007/s11357-024-01281-2},
issn = {2509-2723},
year = {2025},
date = {2025-02-00},
journal = {GeroScience},
volume = {47},
number = {1},
pages = {1019--1037},
publisher = {Springer Science and Business Media LLC},
abstract = {Abstract
Gamma entrainment through sensory stimulation has the potential to reduce the pathology of Alzheimer’s disease in mouse models. However, clinical trials in Alzheimer’s disease (AD) patients have yielded inconsistent results, necessitating further investigation. This single-center pre-post intervention study aims to explore the influence of white matter microstructural integrity on gamma rhythm propagation from the visual cortex to AD-affected regions in 31 cognitively normal volunteers aged ≥ 65. Gamma rhythm propagation induced by optimal FLS was measured. Diffusion tensor imaging was employed to assess the integrity of white matter tracts of interest. After excluding 5 participants with a deficit in steady-state visually evoked potentials, 26 participants were included in the final analysis. In the linear regression analyses, gamma entrainment was identified as a significant predictor of gamma propagation (p < 0.001). Furthermore, the study identified white matter microstructural integrity as a significant predictor of gamma propagation by flickering light stimulation (p < 0.05), which was specific to tracts that connect occipital and temporal or frontal regions. These findings indicate that, despite robust entrainment of gamma rhythms in the visual cortex, their propagation to other regions may be impaired if the microstructural integrity of the white matter tracts connecting the visual cortex to other areas is compromised. Consequently, our findings have expanded our understanding of the prerequisites for effective gamma entrainment and suggest that future clinical trials utilizing visual stimulation for gamma entrainment should consider white matter tract microstructural integrity for candidate selection and outcome analysis.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Abstract
Gamma entrainment through sensory stimulation has the potential to reduce the pathology of Alzheimer’s disease in mouse models. However, clinical trials in Alzheimer’s disease (AD) patients have yielded inconsistent results, necessitating further investigation. This single-center pre-post intervention study aims to explore the influence of white matter microstructural integrity on gamma rhythm propagation from the visual cortex to AD-affected regions in 31 cognitively normal volunteers aged ≥ 65. Gamma rhythm propagation induced by optimal FLS was measured. Diffusion tensor imaging was employed to assess the integrity of white matter tracts of interest. After excluding 5 participants with a deficit in steady-state visually evoked potentials, 26 participants were included in the final analysis. In the linear regression analyses, gamma entrainment was identified as a significant predictor of gamma propagation (p < 0.001). Furthermore, the study identified white matter microstructural integrity as a significant predictor of gamma propagation by flickering light stimulation (p < 0.05), which was specific to tracts that connect occipital and temporal or frontal regions. These findings indicate that, despite robust entrainment of gamma rhythms in the visual cortex, their propagation to other regions may be impaired if the microstructural integrity of the white matter tracts connecting the visual cortex to other areas is compromised. Consequently, our findings have expanded our understanding of the prerequisites for effective gamma entrainment and suggest that future clinical trials utilizing visual stimulation for gamma entrainment should consider white matter tract microstructural integrity for candidate selection and outcome analysis.
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Seok, Hyeon Seok; Kim, Sang Su; Kim, Do-Won; Shin, Hangsik
Toward Objectification of Subjective Chronic Pain Based on Implicit Response in Biosignals Journal Article
In: IEEE Trans. Biomed. Eng., vol. 72, no. 1, pp. 337–345, 2025, ISSN: 1558-2531.
@article{Seok2025,
title = {Toward Objectification of Subjective Chronic Pain Based on Implicit Response in Biosignals},
author = {Hyeon Seok Seok and Sang Su Kim and Do-Won Kim and Hangsik Shin},
doi = {10.1109/tbme.2024.3452708},
issn = {1558-2531},
year = {2025},
date = {2025-01-00},
journal = {IEEE Trans. Biomed. Eng.},
volume = {72},
number = {1},
pages = {337--345},
publisher = {Institute of Electrical and Electronics Engineers (IEEE)},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
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Kim, Jeonghui; Kim, Sang-Su; Jung, Young-Jin; Kim, Do-Won
Enhancing Multiple Steady-State Visual Evoked Potential Responses Using Dual-frequency tACS Domestic Paper
In: 의공학회지, vol. 45, iss. 2, pp. 101-107, 2024, ISSN: 1229-0807.
@domestic{nokey,
title = {Enhancing Multiple Steady-State Visual Evoked Potential Responses Using Dual-frequency tACS},
author = {Jeonghui Kim and Sang-Su Kim and Young-Jin Jung and Do-Won Kim},
doi = {https://doi.org/10.9718/JBER.2024.45.2.101},
issn = {1229-0807},
year = {2024},
date = {2024-04-30},
urldate = {2024-04-30},
journal = {의공학회지},
volume = {45},
issue = {2},
pages = {101-107},
keywords = {},
pubstate = {published},
tppubtype = {domestic}
}
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Park, Yeseung; Lee, Kanghee; Park, Jaehyeok; Bae, Jong Bin; Kim, Sang-Su; Kim, Do-Won; Woo, Se Joon; Yoo, Seunghyup; Kim, Ki Woong
Optimal flickering light stimulation for entraining gamma rhythms in older adults Journal Article
In: Sci Rep, vol. 12, no. 1, 2022, ISSN: 2045-2322.
@article{Park2022,
title = {Optimal flickering light stimulation for entraining gamma rhythms in older adults},
author = {Yeseung Park and Kanghee Lee and Jaehyeok Park and Jong Bin Bae and Sang-Su Kim and Do-Won Kim and Se Joon Woo and Seunghyup Yoo and Ki Woong Kim},
doi = {10.1038/s41598-022-19464-2},
issn = {2045-2322},
year = {2022},
date = {2022-12-00},
journal = {Sci Rep},
volume = {12},
number = {1},
publisher = {Springer Science and Business Media LLC},
abstract = {AbstractWith aging, optimal parameters of flickering light stimulation (FLS) for gamma entrainment may change in the eyes and brain. We investigated the optimal FLS parameters for gamma entrainment in 35 cognitively normal old adults by comparing event-related synchronization (ERS) and spectral Granger causality (sGC) of entrained gamma rhythms between different luminance intensities, colors, and flickering frequencies of FLSs. ERS entrained by 700 cd/m2FLS and 32 Hz or 34 Hz FLSs was stronger than that entrained by 400 cd/m2at Pz (p < 0.01) and 38 Hz or 40 Hz FLSs, respectively, at both Pz (p < 0.05) and Fz (p < 0.01). Parieto-occipital-to-frontotemporal connectivities of gamma rhythm entrained by 700 cd/m2FLS and 32 Hz or 34 Hz FLSs were also stronger than those entrained by 400 cd/m2at Pz (p < 0.01) and 38 Hz or 40 Hz FLSs, respectively (p < 0.001). ERS and parieto-occipital-to-frontotemporal connectivities of entrained gamma rhythms did not show significant difference between white and red lights. Adverse effects were comparable between different parameters. In older adults, 700 cd/m2FLS at 32 Hz or 34 Hz can entrain a strong gamma rhythm in the whole brain with tolerable adverse effects.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
AbstractWith aging, optimal parameters of flickering light stimulation (FLS) for gamma entrainment may change in the eyes and brain. We investigated the optimal FLS parameters for gamma entrainment in 35 cognitively normal old adults by comparing event-related synchronization (ERS) and spectral Granger causality (sGC) of entrained gamma rhythms between different luminance intensities, colors, and flickering frequencies of FLSs. ERS entrained by 700 cd/m2FLS and 32 Hz or 34 Hz FLSs was stronger than that entrained by 400 cd/m2at Pz (p < 0.01) and 38 Hz or 40 Hz FLSs, respectively, at both Pz (p < 0.05) and Fz (p < 0.01). Parieto-occipital-to-frontotemporal connectivities of gamma rhythm entrained by 700 cd/m2FLS and 32 Hz or 34 Hz FLSs were also stronger than those entrained by 400 cd/m2at Pz (p < 0.01) and 38 Hz or 40 Hz FLSs, respectively (p < 0.001). ERS and parieto-occipital-to-frontotemporal connectivities of entrained gamma rhythms did not show significant difference between white and red lights. Adverse effects were comparable between different parameters. In older adults, 700 cd/m2FLS at 32 Hz or 34 Hz can entrain a strong gamma rhythm in the whole brain with tolerable adverse effects.
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Lee, Kanghee; Park, Yeseung; Suh, Seung Wan; Kim, Sang-Su; Kim, Do-Won; Lee, Jaeho; Park, Jaehyeok; Yoo, Seunghyup; Kim, Ki Woong
Optimal flickering light stimulation for entraining gamma waves in the human brain Journal Article
In: Sci Rep, vol. 11, no. 1, 2021, ISSN: 2045-2322.
@article{Lee2021b,
title = {Optimal flickering light stimulation for entraining gamma waves in the human brain},
author = {Kanghee Lee and Yeseung Park and Seung Wan Suh and Sang-Su Kim and Do-Won Kim and Jaeho Lee and Jaehyeok Park and Seunghyup Yoo and Ki Woong Kim},
doi = {10.1038/s41598-021-95550-1},
issn = {2045-2322},
year = {2021},
date = {2021-12-00},
journal = {Sci Rep},
volume = {11},
number = {1},
publisher = {Springer Science and Business Media LLC},
abstract = {AbstractAlthough light flickering at 40 Hz reduced Alzheimer’s disease (AD) pathologies in mice by entraining gamma waves, it failed to reduce cerebral amyloid burden in a study on six patients with AD or mild cognitive impairment. We investigated the optimal color, intensity, and frequency of the flickering light stimulus for entraining gamma waves in young adults. We compared the event-related synchronization (ERS) values of entrained gamma waves between four different light colors (white, red, green, and blue) in the first experiment and four different luminance intensities in the second experiment. In both experiments, we compared the ERS values of entrained gamma waves between 10 different flickering frequencies from 32 to 50 Hz. We also examined the severity of six adverse effects in both experiments. We compared the propagation of gamma waves in the visual cortex to other brain regions between different luminance intensities and flickering frequencies. We found that red light entrained gamma waves most effectively, followed by white light. Lights of higher luminance intensities (700 and 400 cd/m2) entrained stronger gamma waves than those of lower luminance intensities (100 and 10 cd/m2). Lights flickering at 34–38 Hz entrained stronger and more widely spread beyond the visual cortex than those flickering at 40–50 Hz. Light of 700 cd/m2 resulted in more moderate-to-severe adverse effects than those of other luminance intensities. In humans, 400 cd/m2 white light flickering at 34–38 Hz was most optimal for gamma entrainment.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
AbstractAlthough light flickering at 40 Hz reduced Alzheimer’s disease (AD) pathologies in mice by entraining gamma waves, it failed to reduce cerebral amyloid burden in a study on six patients with AD or mild cognitive impairment. We investigated the optimal color, intensity, and frequency of the flickering light stimulus for entraining gamma waves in young adults. We compared the event-related synchronization (ERS) values of entrained gamma waves between four different light colors (white, red, green, and blue) in the first experiment and four different luminance intensities in the second experiment. In both experiments, we compared the ERS values of entrained gamma waves between 10 different flickering frequencies from 32 to 50 Hz. We also examined the severity of six adverse effects in both experiments. We compared the propagation of gamma waves in the visual cortex to other brain regions between different luminance intensities and flickering frequencies. We found that red light entrained gamma waves most effectively, followed by white light. Lights of higher luminance intensities (700 and 400 cd/m2) entrained stronger gamma waves than those of lower luminance intensities (100 and 10 cd/m2). Lights flickering at 34–38 Hz entrained stronger and more widely spread beyond the visual cortex than those flickering at 40–50 Hz. Light of 700 cd/m2 resulted in more moderate-to-severe adverse effects than those of other luminance intensities. In humans, 400 cd/m2 white light flickering at 34–38 Hz was most optimal for gamma entrainment.
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