Studies on Function and its Disorder of the Frontal Association Cortex

我们在猴子实验获得的数据的基础上，研究了猴子的额叶联合皮质的功能及其障碍，然后在人类的基础上进行了研究。研究结果将概括为以下两个主要主题：1.额叶联合皮层的决策(判断)和抑制作用一只猴子被要求进行GO/NO-GO反应时的手部动作，并区分两种不同颜色的光刺激。一种颜色的视觉刺激伴随着奖赏，当猴子在刺激持续时间为500ms内用手举起杠杆时，而另一种颜色的视觉刺激没有。当猴子逐渐停止对后者(no-go)刺激的反应时，在两个大脑半球的前额叶皮质出现并发展出一种电位，特别是对no-go刺激，称为‘no-go Potential’。该电位由潜伏期为85-150ms的表面负向、深度正向(S-N，d-P)偏转组成，定位于主沟和r…背侧。更多的是前额叶皮质的卵腹角。电位的出现和发展模式表明，皮层部位的活动与决定或判断不动以及随后对GO反应的抑制有关。结论：1.大脑皮层刺激实验证实了其抑制作用。额叶联合皮层对刺激到来的预期和注意力我们以固定的时间间隔(如1秒)对猴子进行警告-命令刺激，以便它能在命令刺激开始后立即举起杠杆。事实上，猴子经过足够的训练后，行动的潜伏期很短。根据警告刺激的初始视觉诱发电位，在双侧大脑半球的前额叶和运动前皮质的广域记录到S-N、d-P向命令性刺激的持续慢电位。运动手同侧小脑半球切除对短潜伏期运动几乎没有影响，这与单纯的反应时手运动有很大的不同。这可能暗示在警示-命令性刺激条件下，额叶联合皮层的持续活动可以在一定程度上克服小脑功能缺陷。在人类受试者身上的研究也记录了同样进行/不进行任务的人类头皮的不进行电位。它广泛地分布在头皮的前部，最大的是在头顶(Fz)。警示-命令性刺激在头皮上引起条件性负变异(CNV)。额叶联合皮质的持续活动必须与对即将到来的刺激的精神集中有关。较少

We investigated function of the frontal association cortex and its disorder in monkeys, and then in humans on the basis of data obtained by monkey experiments. The results will be summarized in two main topics as follows.1. The frontal association cortex for decision (judgment) and suppressor action A monkey was tasked with go/no-go reaction-time hand movement with discrimination between two different color light stimuli. Visual stimulus of a color was accompanied by reward when the monkey lifted a lever by its hand within 500 ms duration of the stimulus, whereas that of another color was not. When the monkey gradually ceased in responding to the latter (no-go) stimulus, a potential appeared and developed in the prefrontal cortex of both hemispheres, specifically to the no-go stimulus, called 'no-go potential'. The potential is composed of surface-negative, depth-positive (s-N, d-P) deflections at a latency of 85-150 ms and localized in the dorsal bank of the principal sulcus and the r … More ostroventral corner of the prefrontal cortex. Modes of appearance and development of the potential suggest that the activity of the cortical loci is related to decision or judgment not to move and to subsequent suppression of the go reaction. The suppressor action was substantiated by stimulation experiment of the cortical loci.2. The frontal association cortex for expectancy of coming stimulus and mental concentration We gave warning-imperative stimuli with a fixed time interval (e. g. ls) to a monkey so that it could lift a lever immediately after the onset of imperative stimulus. In fact, the monkey, after enough trained, moved at very short latencies. Following initial visual evoked potentials on the warning stimulus, s-N, d-P sustained slow potentials toward the imperative stimulus were recorded in wide areas of the prefrontal and premotor cortices in both hemispheres. The short latency movement was scarcely in fluenced by cerebellar hemispherectomy ipsilateral to the moving hand, which was quite different from the case of simple reaction-time hand movement. This may imply that the sustained activity of the frontal association cortex on the warning-imperative stimulus can overcome cerebellar deficiency to some extent.3. Studies in human subjects No-go potential was recorded also from the human scalp on the same go/no-go task. It spreads over the frontal part of scalp widely with the maximum at the vertex (Fz). The warning-imperative stimulus induces contingent negative variation (CNV) on the human scalp. Sustained activities of the frontal association cortex must be related to mental concentration on the coming stimulus. Less