Involvement of the central thalamus in the control of smooth pursuit eye movements
Involvement of the central thalamus in the control of smooth pursuit eye movements
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DOI：
10.1523/jneurosci.0676-05.2005
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发表时间：
2005-06-22
影响因子：
5.3
通讯作者：
Tanaka, M
中科院分区：
文献类型：
--
作者：
Tanaka, M
在维持平滑的追踪眼球运动期间，大脑必须跟踪追踪速度，以便从视网膜图像的运动中重建目标速度。尽管最近的一项研究表明，通过丘脑到皮质的推论放电信号可用于眼跳的内部监测，但丘脑中的信号是否也有助于平滑追踪的监测和在线调节仍不清楚。本研究通过记录单个丘脑神经元的活动并分析局部失活的影响来寻找丘脑皮质通路在追踪中的可能作用。数据显示，腹外侧丘脑的许多神经元在追逐过程中表现出定向调节。大多数神经元在追踪开始之前或追踪期间放电，放电率与目标在首选方向上运动的速度成正比。当跟踪目标在维持追踪过程中短暂熄灭时，这些神经元继续放电，表明它们携带视网膜外的眼球运动信号。大多数神经元在追踪期间的小追赶扫视期间没有表现出活动变化，但对首选追踪方向上的大（16度）记忆引导扫视做出短暂反应。记录位点的局部失活不会改变追踪潜伏期，但会在启动和维持同向追踪过程中适度降低眼速。结果表明，中央丘脑位于调节和监控平滑追踪眼运动的通路内。
During maintenance of smooth pursuit eye movements, the brain must keep track of pursuit velocity to reconstruct target velocity from motion of retinal images. Although a recent study showed that corollary discharge signals through the thalamus to the cortex are used for internal monitoring of saccades, it remains unknown whether signals in the thalamus also contribute to monitoring and on-line regulation of smooth pursuit. The present study sought possible roles of the thalamocortical pathways in pursuit by recording activities of single thalamic neurons and by analyzing the effects of local inactivation. Data showed that many neurons in the ventrolateral thalamus exhibited directional modulation during pursuit. Most neurons discharged before or during initiation of pursuit, and the firing rate was proportional to the speed of target motion in a preferred direction. When the tracking target was extinguished briefly during maintenance of pursuit, these neurons continued firing, indicating that they carried extra-retinal, eye movement signals. The majority of neurons showed no change in activity around the time of small catch-up saccades during pursuit but responded transiently to large (16 degrees) memory-guided saccades in the preferred pursuit direction. Local inactivation of the recording sites did not alter pursuit latency but reduced eye velocity modestly during initiation and maintenance of ipsiversive pursuit. The results suggest that the central thalamus lies within pathways that regulate and monitor smooth pursuit eye movements.