CEREBRAL CORTICAL MECHANISMS FOR EYE MOVEMENTS AND VISUAL ATTENTION

逆行刺激大脑皮层神经元上丘 弧形的额叶视野，确定细胞有眼睛 移动或注视信号，但不包括周边视觉信号 信息从额叶皮质投射到上丘。 这意味着大脑皮层只向 脑干眼球跳动系统。 接受扫视适应范式训练的猴子很快就会学会改变 他们对视交叉内刺激反应的眼跳幅度 台阶。在适应病例中刺激上丘产生 与未适应的情况相同的眼跳。单个神经元的活动 也没有显示适应的证据：视觉和运动信号 丘脑发出的是刺激和刺激的垂直信号 运动，而不是被修改的视觉帧中的运动信号 通过脑干。因此，跳跃幅度的变化发生在 适应的结果在神经链的早期位置得到补偿 从刺激到反应。 有阅读障碍的人中有一小部分人有注视 不稳定表现为跳动侵入或方波跳动，而他们 试着凝视一点光。单剂哌甲酸甲酯 减少或消除眼跳干扰，并导致暂时的 在口头阅读和阅读的视觉机制方面都有所改善 表演本身。

By antidromic stimulation in the superior colliculus of neurons in the arcuate frontal eye fields, it was determined that cells bearing eye movement or fixation signals but not those with peripheral visual information project to the superior colliculus from the frontal cortex. This implies that the cerebral cortex sends only a motor message to the brainstem saccadic eye movement system. Monkeys trained on a saccadic adaptation paradigm learn quickly to change the amplitude of their saccades in response to intrasaccadic stimulus steps. Stimulation of the superior colliculus in the adapted case yields the same saccades as the unadapted case. The activity of single neurons also shows no evidence of adaptation: the visual and movement signals emanating from the colliculus are the veridical signals for stimulus and movement, rather than movement signals in a visual frame which are modified by the brainstem. Thus the change in saccade amplitude which occurs as a result of adaptation is compensated for at early sites in the neural chain from stimulus to response. A small percentage of humans with reading disorders have fixational instability manifest by saccadic intrusions or square-wave jerks while they attempt to fixate a spot of light. A single dose of methylphenidate decreases or eliminates the saccadic intrusions and results in temporary improves in both the ocular mechanics of oral reading and the reading performance itself.