Suppression of visually and memory-guided saccades induced by electrical stimulation of the monkey frontal eye field. I. Suppression of ipsilateral saccades
Suppression of visually and memory-guided saccades induced by electrical stimulation of the monkey frontal eye field. I. Suppression of ipsilateral saccades
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DOI：
10.1152/jn.01021.2003
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发表时间：
2004-10-01
影响因子：
2.5
通讯作者：
Shinoda, Y
中科院分区：
文献类型：
--
作者：
Izawa, Y;Suzuki, H;Shinoda, Y
当眼跳发生在一个感兴趣的物体上时，视觉注视将其图像保持在中央凹上，并抑制对其他物体的眼跳。据报道，额眼场（FEF）的电刺激引起扫视，并且最近还抑制扫视。进行本研究以表征在训练的猴子中由FEF的电刺激诱导的视觉引导（Vsacs）和记忆引导的扫视（Msacs）的抑制特性。对于任何给定的刺激部位，我们确定电诱发扫视（Esacs）的阈值小于或等于50 μ A，然后检查在相同部位刺激对Vsacs和Msacs的抑制作用。FEF刺激抑制Vsacs和Msacs的启动期间和约50毫秒后，刺激强度低于那些引发Esacs的刺激，但不影响这些扫视的载体。抑制发生同向扫视，但不是逆向扫视，更强烈的扫视幅度较大，那些与初始眼位置转移更多的扫视方向。抑制的最有效的刺激时间是大约50毫秒前扫视发作，这表明抑制发生在传出通路产生Vsac在前运动，而不是运动神经元水平，最有可能在上级丘和/或旁正中脑桥网状结构。同侧眼跳抑制部位分布在经典的FEF上，在那里观察到眼跳相关的运动神经元。结果表明，FEF不仅可以产生逆向眼跳，而且可以通过抑制同向眼跳来维持视觉注视。
When a saccade occurs to an interesting object, visual fixation holds its image on the fovea and suppresses saccades to other objects. Electrical stimulation of the frontal eye field (FEF) has been reported to elicit saccades, and recently also to suppress saccades. This study was performed to characterize properties of the suppression of visually guided (Vsacs) and memory-guided saccades (Msacs) induced by electrical stimulation of the FEF in trained monkeys. For any given stimulation site, we determined the threshold for electrically evoked saccades (Esacs) at less than or equal to50 muA and then examined suppressive effects of stimulation at the same site on Vsacs and Msacs. FEF stimulation suppressed the initiation of both Vsacs and Msacs during and about 50 ms after stimulation at stimulus intensities lower than those for eliciting Esacs, but did not affect the vector of these saccades. Suppression occurred for ipsiversive but not contraversive saccades, and more strongly for saccades with larger amplitudes and those with initial eye positions shifted more in the saccadic direction. The most effective stimulation timing for suppression was about 50 ms before saccade onset, which suggests that suppression occurred in the efferent pathway for generating Vsacs at the premotor rather than the motoneuronal level, most probably in the superior colliculus and/or the paramedian pontine reticular formation. Suppression sites of ipsilateral saccades were distributed over the classical FEF where saccade-related movement neurons were observed. The results suggest that the FEF may play roles in not only generating contraversive saccades but also maintaining visual fixation by suppressing ipsiversive saccades.