Barborica Andrei, Ferrera Vincent P
Department of Psychiatry, Center for Neurobiology and Behavior, Keck-Mahoney Center for Brain and Behavior Research, Columbia University, New York, New York 10032, USA.
J Neurosci. 2004 Mar 31;24(13):3260-7. doi: 10.1523/JNEUROSCI.4702-03.2004.
We investigated the internal representation of invisible moving targets using electrical microstimulation in the prefrontal cortex. Monkeys were trained to make saccades to the extrapolated position of a small moving target that was rendered invisible during part of its trajectory. Although the target was invisible, involuntary saccades were evoked by electrical microstimulation of the frontal eye field. Stimulation was applied at different times relative to the disappearance of the target while the monkey fixated. When stimulation was applied immediately after target disappearance, electrically evoked saccades were biased toward the starting point of the target trajectory. When stimulation was applied later in the trial, evoked saccades were biased toward the end of the trajectory. The bias in evoked saccade direction changed continuously over time. The magnitude and statistical significance of the electrically evoked saccade deviation depended on the accuracy of the monkeys' voluntary saccades relative to the invisible target. The results suggest that covert tracking is accompanied by a continuously shifting saccade plan that moves along the target path.
我们利用前额叶皮质的电微刺激来研究不可见移动目标的内部表征。训练猴子对一个小的移动目标的外推位置进行扫视，该目标在其部分轨迹中是不可见的。尽管目标不可见，但额叶眼区的电微刺激会诱发非自愿扫视。在猴子注视时，相对于目标消失的不同时间施加刺激。当在目标消失后立即施加刺激时，电诱发扫视偏向目标轨迹的起点。当在试验后期施加刺激时，诱发扫视偏向轨迹的终点。诱发扫视方向的偏差随时间持续变化。电诱发扫视偏差的大小和统计学意义取决于猴子相对于不可见目标的自愿扫视的准确性。结果表明，隐蔽跟踪伴随着一个沿着目标路径不断移动的扫视计划。
