Ryan Jennifer D, Shen Kelly, Kacollja Arber, Tian Heather, Griffiths John, Bezgin Gleb, McIntosh Anthony R
Rotman Research Institute, Baycrest, Toronto, Ontario, Canada.
Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
Netw Neurosci. 2020 Mar 1;4(1):217-233. doi: 10.1162/netn_a_00120. eCollection 2020.
Visual exploration is related to activity in the hippocampus (HC) and/or extended medial temporal lobe system (MTL), is influenced by stored memories, and is altered in amnesic cases. An extensive set of polysynaptic connections exists both within and between the HC and oculomotor systems such that investigating how HC responses ultimately influence neural activity in the oculomotor system, and the timing by which such neural modulation could occur, is not trivial. We leveraged TheVirtualBrain, a software platform for large-scale network simulations, to model the functional dynamics that govern the interactions between the two systems in the macaque cortex. Evoked responses following the stimulation of the MTL and some, but not all, subfields of the HC resulted in observable responses in oculomotor regions, including the frontal eye fields, within the time of a gaze fixation. Modeled lesions to some MTL regions slowed the dissipation of HC signal to oculomotor regions, whereas HC lesions generally did not affect the rapid MTL activity propagation to oculomotor regions. These findings provide a framework for investigating how information represented by the HC/MTL may influence the oculomotor system during a fixation and predict how HC lesions may affect visual exploration.
视觉探索与海马体（HC）和/或扩展的内侧颞叶系统（MTL）的活动有关，受存储记忆的影响，并且在失忆病例中会发生改变。在HC和动眼系统内部以及它们之间存在着广泛的多突触连接，因此研究HC反应如何最终影响动眼系统中的神经活动，以及这种神经调制可能发生的时间，并非易事。我们利用了TheVirtualBrain，一个用于大规模网络模拟的软件平台，来模拟猕猴大脑皮层中两个系统之间相互作用的功能动力学。刺激MTL和HC的一些（但不是全部）子区域后诱发的反应，在注视时间内导致了动眼区域（包括额叶眼区）的可观察到的反应。对一些MTL区域的模拟损伤减缓了HC信号向动眼区域的消散，而HC损伤通常不会影响MTL活动向动眼区域的快速传播。这些发现为研究HC/MTL所代表的信息在注视过程中如何影响动眼系统提供了一个框架，并预测了HC损伤可能如何影响视觉探索。
