Nürnberger Matthias, Klingner Carsten, Witte Otto W, Brodoehl Stefan
Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
Biomagnetic Center, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
Front Hum Neurosci. 2021 Oct 29;15:757735. doi: 10.3389/fnhum.2021.757735. eCollection 2021.
Visually induced motion sickness (VIMS) is a relevant limiting factor in the use of virtual reality (VR) devices. Understanding the origin of this problem might help to develop strategies to circumvent this limitation. Previous studies have attributed VIMS to a mismatch between visual, and vestibular information, causing ambiguity of the position of the body in relation to its surrounding. Studies using EEG have shown a shift of the power spectrum to lower frequencies while VIMS is experienced. However, little is known about the relationship between the intensity of the VIMS and the changes in these power spectra. Moreover, the effect of different varieties of VIMS on the causal relationship between brain areas is largely unknown. Here, we used EEG to study 14 healthy subjects in a VR environment who were exposed to increasing levels of mismatch between vestibular and visual information. The frequency power and the bivariate transfer entropy as a measure for the information transfer were calculated. We found a direct association between increasing mismatch levels and subjective VIMS. With increasing VIMS, the proportion of slow EEG waves (especially 1-10 Hz) increases, especially in temporo-occipital regions. Furthermore, we found a general decrease in the information flow in most brain areas but especially in brain areas involved in the processing of vestibular signals and the detection of self-motion. We hypothesize that the general shift of frequency power and the decrease in information flow while experiencing high intensity VIMS represent a brain state of a reduced ability to receive, transmit and process information. We further hypothesize that the mechanism of reduced information flow is a general reaction of the brain to an unresolvable mismatch of information. This reaction aims on transforming a currently unstable model with a high prediction error into a stable model in an environment of minimal contradictory information.
视觉诱发晕动病（VIMS）是虚拟现实（VR）设备使用中的一个重要限制因素。了解这一问题的根源可能有助于制定规避这一限制的策略。先前的研究将VIMS归因于视觉和前庭信息之间的不匹配，导致身体相对于周围环境位置的模糊性。使用脑电图（EEG）的研究表明，在体验VIMS时，功率谱会向低频转移。然而，关于VIMS强度与这些功率谱变化之间的关系知之甚少。此外，不同类型的VIMS对脑区之间因果关系的影响在很大程度上尚不清楚。在这里，我们使用脑电图研究了14名健康受试者在VR环境中暴露于前庭和视觉信息之间不匹配程度不断增加的情况。计算了频率功率和作为信息传递度量的双变量转移熵。我们发现不匹配水平的增加与主观VIMS之间存在直接关联。随着VIMS的增加，脑电图慢波（尤其是1-10赫兹）的比例增加，特别是在颞枕区。此外，我们发现大多数脑区的信息流普遍减少，但特别是参与前庭信号处理和自我运动检测的脑区。我们假设，在体验高强度VIMS时频率功率的普遍转移以及信息流的减少代表了大脑接收、传输和处理信息能力下降的一种脑状态。我们进一步假设，信息流减少的机制是大脑对无法解决的信息不匹配的一种普遍反应。这种反应旨在在矛盾信息最少的环境中将当前具有高预测误差的不稳定模型转变为稳定模型。
