Department of Cognitive Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, Göttingen 37075, Germany; German Center for Addiction Research in Childhood and Adolescence, University Medical Center Hamburg-Eppendorf, Martinistr. 52, Hamburg 20246, Germany; Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, Goettingen 37075, Germany.
Department of Neurology, University Medicine Göttingen, Robert-Koch-Str. 40, Goettingen 37075, Germany; DFG Center for Nanoscale Microscopy & Molecular Physiology of the Brain (CNMPB), Germany.
Neuroimage Clin. 2019;23:101898. doi: 10.1016/j.nicl.2019.101898. Epub 2019 Jun 22.
The rotation of the trunk around its vertical midline could be shown to bias visuospatial temporal judgments towards targets in the hemifield ipsilateral to the trunk orientation and to improve visuospatial performance in patients with visual neglect. However, the underlying brain mechanisms are not well understood. Therefore, the goal of the present study was to investigate the neural effects associated with egocentric midplane shifts under consideration of individual handedness. We employed a visuospatial temporal order judgment (TOJ) task in healthy right- and left-handed subjects while their trunk rotation was varied. Participants responded by a saccade towards the stimulus perceived first out of two stimuli presented with different stimulus onset asynchronies (SOA). Apart from gaze behavior, BOLD-fMRI responses were measured using functional magnetic resonance imaging (fMRI). Based on findings from spatial neglect research, analyses of fMRI-BOLD responses were focused on a bilateral fronto-temporo-parietal network comprising Brodmann areas 22, 39, 40, and 44, as well as the basal ganglia core nuclei (caudate, putamen, pallidum). We observed an acceleration of saccadic speed towards stimuli ipsilateral to the trunk orientation modulated by individual handedness. Left-handed participants showed the strongest behavioral and neural effects, suggesting greater susceptibility to manipulations of trunk orientation. With respect to the dominant hand, a rotation around the vertical trunk midline modulated the activation of an ipsilateral network comprising fronto-temporo-parietal regions and the putamen with the strongest effects for saccades towards the hemifield opposite to the dominant hand. Within the investigated network, the temporo-parietal junction (TPJ) appears to serve as a region integrating sensory, motor, and trunk position information. Our results are discussed in the context of gain modulatory and laterality effects.
躯干绕其垂直中线的旋转被证明会使视空间时间判断偏向于与躯干朝向相对侧的视野中的目标，并改善视觉忽视患者的视空间表现。然而，其潜在的大脑机制尚不清楚。因此，本研究的目的是在考虑个体利手的情况下，研究与自我中心中面移位相关的神经效应。我们在健康的右利手和左利手受试者中进行了视空间时间顺序判断（TOJ）任务，同时改变了他们的躯干旋转。参与者通过扫视对两个刺激中的第一个刺激做出反应，这两个刺激以不同的刺激起始时间间隔（SOA）呈现。除了注视行为外，还使用功能磁共振成像（fMRI）测量了 BOLD-fMRI 反应。基于空间忽视研究的结果，对 fMRI-BOLD 反应的分析集中在一个双侧额颞顶叶-顶叶网络上，包括布罗德曼区 22、39、40 和 44 以及基底节核心核（尾状核、壳核、苍白球）。我们观察到，朝向与躯干朝向相对侧的刺激的扫视速度随个体利手而加速。左利手参与者表现出最强的行为和神经效应，这表明他们对躯干朝向的操纵更为敏感。就优势手而言，围绕垂直躯干中线的旋转调节了一个包含额颞顶叶区域和壳核的同侧网络的激活，对朝向与优势手相对侧的视野的扫视具有最强的影响。在所研究的网络中，颞顶联合（TPJ）似乎作为一个整合感觉、运动和躯干位置信息的区域。我们的结果在增益调节和偏侧性效应的背景下进行了讨论。
