Schröder Rebekka, Kasparbauer Anna-Maria, Meyhöfer Inga, Steffens Maria, Trautner Peter, Ettinger Ulrich
Department of Psychology, University of Bonn, Bonn, Germany.
Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.
J Neurophysiol. 2020 Dec 1;124(6):1839-1856. doi: 10.1152/jn.00317.2020. Epub 2020 Sep 30.
Smooth pursuit eye movements (SPEM) hold the image of a slowly moving stimulus on the fovea. The neural system underlying SPEM primarily includes visual, parietal, and frontal areas. In the present study, we investigated how these areas are functionally coupled and how these couplings are influenced by target motion frequency. To this end, healthy participants ( = 57) were instructed to follow a sinusoidal target stimulus moving horizontally at two different frequencies (0.2 Hz, 0.4 Hz). Eye movements and blood oxygen level-dependent (BOLD) activity were recorded simultaneously. Functional connectivity of the key areas of the SPEM network was investigated with a psychophysiological interaction (PPI) approach. How activity in five eye movement-related seed regions (lateral geniculate nucleus, V1, V5, posterior parietal cortex, frontal eye fields) relates to activity in other parts of the brain during SPEM was analyzed. The behavioral results showed clear deterioration of SPEM performance at higher target frequency. BOLD activity during SPEM versus fixation occurred in a geniculo-occipito-parieto-frontal network, replicating previous findings. PPI analysis yielded widespread, partially overlapping networks. In particular, frontal eye fields and posterior parietal cortex showed task-dependent connectivity to large parts of the entire cortex, whereas other seed regions demonstrated more regionally focused connectivity. Higher target frequency was associated with stronger activations in visual areas but had no effect on functional connectivity. In summary, the results confirm and extend previous knowledge regarding the neural mechanisms underlying SPEM and provide a valuable basis for further investigations such as in patients with SPEM impairments and known alterations in brain connectivity. This study provides a comprehensive investigation of blood oxygen level-dependent (BOLD) functional connectivity during smooth pursuit eye movements. Results from a large sample of healthy participants suggest that key oculomotor regions interact closely with each other but also with regions not primarily associated with eye movements. Understanding functional connectivity during smooth pursuit is important, given its potential role as an endophenotype of psychoses.
平稳跟踪眼球运动（SPEM）将缓慢移动的刺激图像保持在中央凹上。SPEM背后的神经系统主要包括视觉、顶叶和额叶区域。在本研究中，我们调查了这些区域是如何进行功能耦合的，以及这些耦合如何受到目标运动频率的影响。为此，我们指示57名健康参与者跟踪以两种不同频率（0.2赫兹、0.4赫兹）水平移动的正弦目标刺激。同时记录眼球运动和血氧水平依赖（BOLD）活动。采用心理生理交互作用（PPI）方法研究了SPEM网络关键区域的功能连接性。分析了五个与眼球运动相关的种子区域（外侧膝状体核、V1、V5、后顶叶皮质、额叶眼区）在SPEM过程中的活动与大脑其他部位活动的关系。行为结果显示，在较高目标频率下，SPEM性能明显下降。与注视相比，SPEM期间的BOLD活动发生在一个膝状体-枕叶-顶叶-额叶网络中，重复了先前的研究结果。PPI分析产生了广泛的、部分重叠的网络。特别是，额叶眼区和后顶叶皮质显示出与整个皮质大部分区域的任务依赖性连接，而其他种子区域则表现出更具区域针对性的连接。较高的目标频率与视觉区域更强的激活相关，但对功能连接没有影响。总之，这些结果证实并扩展了先前关于SPEM潜在神经机制的知识，并为进一步的研究（如对SPEM受损和已知脑连接改变的患者的研究）提供了有价值的基础。本研究对平稳跟踪眼球运动期间的血氧水平依赖（BOLD）功能连接进行了全面调查。大量健康参与者的结果表明，关键的眼球运动区域不仅相互之间密切互动，而且还与并非主要与眼球运动相关的区域相互作用。鉴于平稳跟踪作为精神病内表型的潜在作用，了解其功能连接很重要。
