Smith-Kettlewell Eye Research Institute, 2318 Fillmore St., San Francisco, CA 94115, USA.
J Neurophysiol. 2011 Dec;106(6):2992-3000. doi: 10.1152/jn.01134.2010. Epub 2011 Sep 7.
Since the environment is in constant flux, decision-making capabilities of the brain must be rapid and flexible. Yet in sensory motion processing pathways of the primate brain where decision making has been extensively studied, the flexibility of neurons is limited by inherent selectivity to motion direction and speed. The supplementary eye field (SEF), an area involved in decision making on moving stimuli, is not strictly a sensory or motor structure, and hence may not suffer such limitations. Here we test whether neurons in the SEF can flexibly interpret the rule of a go/nogo task when the decision boundary in the task changes with each trial. The task rule specified that the animal pursue a moving target with its eyes if and when the target entered a visible zone. The size of the zone was changed from trial to trial in order to shift the decision boundary, and thereby assign different go/nogo significance to the same motion trajectories. Individual SEF neurons interpreted the rule appropriately, signaling go or nogo in compliance with the rule and not the direction of motion. The results provide the first evidence that individual neurons in frontal cortex can flexibly interpret a rule that governs the decision to act.
由于环境在不断变化，大脑的决策能力必须快速而灵活。然而，在灵长类动物大脑的感觉运动处理通路中，尽管已经广泛研究了决策制定，但神经元的灵活性受到运动方向和速度固有选择性的限制。补充眼区（SEF）是参与运动刺激决策的区域，它不是严格的感觉或运动结构，因此可能不会受到这种限制。在这里，我们测试了当任务中的决策边界在每次试验中都发生变化时，SEF 中的神经元是否可以灵活地解释 Go/NoGo 任务的规则。任务规则规定，如果目标进入可见区域，动物就用眼睛追踪移动的目标。区域的大小会在每次试验中改变，以改变决策边界，从而为相同的运动轨迹赋予不同的 Go/NoGo 意义。个别 SEF 神经元根据规则适当地解释了规则，根据规则而不是运动方向发出 Go 或 NoGo 信号。结果提供了第一个证据，表明额皮质中的单个神经元可以灵活地解释控制行为决策的规则。
