Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Leuven, Belgium.
Laboratory for Neuro- and Psychophysiology, Department of Neurosciences, KU Leuven, Leuven, Belgium.
Neuroimage. 2018 Jul 15;175:315-326. doi: 10.1016/j.neuroimage.2018.04.006. Epub 2018 Apr 7.
Despite the widespread use of steady-state visual evoked potentials (SSVEPs) elicited by luminance flicker in clinical and research settings, their spatial and temporal representation in the occipital cortex largely remain elusive. We performed intracranial-EEG recordings in response to targets flickering at frequencies from 11 to 15 Hz using a subdural electrode grid covering the entire right occipital cortex of a human subject, and we were able to consistently locate the gazed stimulus frequency at the posterior side of the primary visual cortex (V1). Peripheral flickering, undetectable in scalp-EEG, elicited activations in the interhemispheric fissure at locations consistent with retinotopic maps. Both foveal and peripheral activations spatially coincided with activations in the high gamma band. We detected localized alpha synchronization at the lateral edge of V2 during stimulation and transient post-stimulation theta band activations at the posterior part of the occipital cortex. Scalp-EEG exhibited only a minor occipital post-stimulation theta activation, but a strong transient frontal activation.
尽管在临床和研究环境中广泛使用亮度闪烁引起的稳态视觉诱发电位（SSVEPs），但其在枕叶皮层中的空间和时间表示仍难以捉摸。我们使用覆盖人类受试者整个右枕叶皮层的硬膜下电极网格，对频率在 11 到 15 Hz 之间的目标进行了颅内 EEG 记录，并且能够始终将注视刺激频率定位在初级视觉皮层（V1）的后侧。头皮 EEG 无法检测到的外周闪烁在与视拓扑图一致的位置在半球间裂中引起激活。中央凹和外周激活在空间上与高伽马波段的激活重合。在刺激期间，我们在 V2 的外侧边缘检测到局部 alpha 同步，并且在枕叶皮层的后部检测到短暂的刺激后 theta 波段激活。头皮 EEG 仅显示轻微的枕叶刺激后 theta 激活，但强烈的短暂额叶激活。
