Salari Neda, Büchel Christian, Rose Michael
Department of Systems Neuroscience, University Medical Center Hamburg Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany,
Exp Brain Res. 2014 Oct;232(10):3353-61. doi: 10.1007/s00221-014-4023-9. Epub 2014 Jul 4.
In this study, a noninvasive electroencephalography-based neurofeedback method is applied to train volunteers to deliberately increase gamma band oscillations (40 Hz) in the visual cortex. Gamma band oscillations in the visual cortex play a functional role in perceptual processing. In a previous study, we were able to demonstrate that gamma band oscillations prior to stimulus presentation have a significant influence on perceptual processing of visual stimuli. In the present study, we aimed to investigate longer lasting effects of gamma band neurofeedback training on perceptual processing. For this purpose, a feedback group was trained to modulate oscillations in the gamma band, while a control group participated in a task with an identical design setting but without gamma band feedback. Before and after training, both groups participated in a perceptual object detection task and a spatial attention task. Our results clearly revealed that only the feedback group but not the control group exhibited a visual processing advantage and an increase in oscillatory gamma band activity in the pre-stimulus period of the processing of the visual object stimuli after the neurofeedback training. Results of the spatial attention task showed no difference between the groups, which underlines the specific role of gamma band oscillations for perceptual processing. In summary, our results show that modulation of gamma band activity selectively affects perceptual processing and therefore supports the relevant role of gamma band activity for this specific process. Furthermore, our results demonstrate the eligibility of gamma band oscillations as a valuable tool for neurofeedback applications.
在本研究中，一种基于无创脑电图的神经反馈方法被用于训练志愿者有意识地增强视觉皮层中的伽马波段振荡（40赫兹）。视觉皮层中的伽马波段振荡在感知处理中发挥着功能性作用。在先前的一项研究中，我们能够证明刺激呈现之前的伽马波段振荡对视觉刺激的感知处理有显著影响。在本研究中，我们旨在探究伽马波段神经反馈训练对感知处理的更持久影响。为此，一个反馈组被训练来调节伽马波段的振荡，而一个对照组参与了一个设计设置相同但没有伽马波段反馈的任务。训练前后，两组都参与了一个感知物体检测任务和一个空间注意力任务。我们的结果清楚地表明，只有反馈组而非对照组在神经反馈训练后，在视觉物体刺激处理的刺激前阶段表现出视觉处理优势以及振荡伽马波段活动增加。空间注意力任务的结果显示两组之间没有差异，这突出了伽马波段振荡在感知处理中的特定作用。总之，我们的结果表明，伽马波段活动的调节选择性地影响感知处理，因此支持了伽马波段活动在这一特定过程中的相关作用。此外，我们的结果证明了伽马波段振荡作为神经反馈应用的一种有价值工具的适用性。
