Lin Zhenglong, Hou Gangqiang, Yao Youli, Zhou Zhifeng, Zhu Feiqi, Liu Linjing, Zeng Lingwu, Yang Yatao, Ma Junxian
College of Electronics and Information Engineering, Shenzhen University, Shenzhen, China.
Department of Radiology, Shenzhen Kangning Hospital, Shenzhen Mental Health Center, Shenzhen, China.
Front Hum Neurosci. 2021 Dec 16;15:739333. doi: 10.3389/fnhum.2021.739333. eCollection 2021.
Research on light modulation has typically examined the wavelength, intensity, and exposure time of light, and measured rhythm, sleep, and cognitive ability to evaluate the regulatory effects of light variables on physiological and cognitive functions. Although the frequency of light is one of the main dimensions of light, few studies have attempted to manipulate it to test the effect on brain activation and performance. Recently, 40-Hz light stimulation has been proven to significantly alleviate deficits in gamma oscillation of the hippocampus caused by Alzheimer's disease. Although this oscillation is one of the key functional characteristics of performing memory tasks in healthy people, there is no evidence that 40-Hz blue light exposure can effectively regulate brain activities related to complex cognitive tasks. In the current study, we examined the difference in the effects of 40-Hz light or 0-Hz light exposure on brain activation and functional connectivity during a recognition memory task. Through joint augmentation of visual area activation, 40-Hz light enhanced brain areas mostly in the limbic system that are related to memory, such as the hippocampus and thalamus. Conversely, 0-Hz light enhanced brain areas mostly in the prefrontal cortex. Additionally, functional connection analysis, with the hippocampus as the seed point, showed that 40-Hz light enhanced connection with the superior parietal lobe and reduced the connection with the default network. These results indicate that light at a frequency of 40 Hz can change the activity and functional connection of memory-related core brain areas. They also indicate that in the use of light to regulate cognitive functions, its frequency characteristics merit attention.
对光调制的研究通常考察光的波长、强度和照射时间，并测量节律、睡眠和认知能力，以评估光变量对生理和认知功能的调节作用。尽管光的频率是光的主要维度之一，但很少有研究尝试操纵它来测试其对大脑激活和表现的影响。最近，已证明40赫兹的光刺激能显著减轻阿尔茨海默病导致的海马体γ振荡缺陷。尽管这种振荡是健康人执行记忆任务的关键功能特征之一，但没有证据表明暴露于40赫兹的蓝光能有效调节与复杂认知任务相关的大脑活动。在当前的研究中，我们考察了在识别记忆任务期间，暴露于40赫兹或0赫兹的光对大脑激活和功能连接的影响差异。通过联合增强视觉区域的激活，40赫兹的光增强了主要位于与记忆相关的边缘系统中的大脑区域，如海马体和丘脑。相反，0赫兹的光增强了主要位于前额叶皮层的大脑区域。此外，以海马体为种子点的功能连接分析表明，40赫兹的光增强了与顶上叶的连接，并减少了与默认网络的连接。这些结果表明，40赫兹的光可以改变与记忆相关的核心大脑区域的活动和功能连接。它们还表明，在利用光调节认知功能时，其频率特性值得关注。
