Paladini Rebecca E, Müri René M, Meichtry Jurka, Nef Tobias, Mast Fred W, Mosimann Urs P, Nyffeler Thomas, Cazzoli Dario
Gerontechnology and Rehabilitation Group, University of Bern, Bern, Switzerland.
Perception and Eye Movement Laboratory, Departments of Neurology and Clinical Research, Inselspital, University Hospital Bern, and University of Bern, Bern, Switzerland.
Cereb Cortex. 2017 Jan 1;27(1):233-243. doi: 10.1093/cercor/bhw390.
With a reduced level of alertness, healthy individuals typically show a rightward shift when deploying visual attention in space. The impact of alertness on the neural networks governing visuospatial attention is, however, poorly understood. By using a transcranial magnetic stimulation twin-coil approach, the present study aimed at investigating the effects of an alertness manipulation on the excitability of the left and the right posterior parietal cortices (PPCs), crucial nodes of the visuospatial attentional network. Participants' visuospatial attentional deployment was assessed with a free visual exploration task and concurrent eye tracking. Their alertness level was manipulated through the time of the day, that is, by testing chronotypically defined evening types both during their circadian on- and off-peak times. The results revealed an increased excitability of the left compared with the right PPC during low alertness. On the horizontal dimension, these results were accompanied by a significant rightward shift in the center and a bilateral narrowing in the periphery of the visual exploration field, as well as a central upward shift on the vertical dimension. The findings show that the manipulation of non-spatial attentional aspects (i.e., alertness) can affect visuospatial attentional deployment and modulate the excitability of areas subtending spatial attentional control.
在警觉性降低的情况下，健康个体在空间中部署视觉注意力时通常会出现向右偏移。然而，警觉性对控制视觉空间注意力的神经网络的影响却知之甚少。本研究采用经颅磁刺激双线圈方法，旨在研究警觉性操纵对左右后顶叶皮质（PPCs）兴奋性的影响，PPCs是视觉空间注意力网络的关键节点。通过自由视觉探索任务和同步眼动追踪来评估参与者的视觉空间注意力部署。通过一天中的时间来操纵他们的警觉性水平，即通过在昼夜节律的高峰和非高峰时间测试按昼夜类型定义的夜型个体。结果显示，在低警觉状态下，左侧PPC的兴奋性高于右侧。在水平维度上，这些结果伴随着视觉探索区域中心显著向右偏移以及周边双侧变窄，以及在垂直维度上中心向上偏移。研究结果表明，对非空间注意力方面（即警觉性）的操纵会影响视觉空间注意力的部署，并调节支持空间注意力控制区域的兴奋性。
