Studies on Function and its Disorder of the Frontal Association Cortex

在猴子实验数据的基础上，我们研究了猴子和人类额叶联合皮层的功能及其紊乱。结果将总结为以下两个主要主题。决定（判断）和抑制作用的额叶关联皮层一只猴子被要求在两种不同的色光刺激下进行“走”/“不走”的手部运动。当一种颜色的视觉刺激在刺激的500毫秒内用手举起杠杆时，猴子会得到奖励，而另一种颜色的视觉刺激则不会。当猴子逐渐停止对后一种刺激（不去）的反应时，两个脑半球的前额叶皮层出现并发展了一个电位，特别是对不去的刺激，称为“不去电位”。电位由表面负、深度正（s-N、d-P）偏转组成，潜伏期85-150 ms，定位于主沟背岸和前额叶皮层的左腹侧角。潜在的出现和发展模式表明，皮质位点的活动与不移动的决定或判断以及随后对go反应的抑制有关。皮质部位的刺激实验证实了其抑制作用。我们以固定的时间间隔（如1秒）对猴子进行警告-命令性刺激，使其在命令性刺激出现后能够立即举起杠杆。事实上，猴子经过足够的训练后，动作的潜伏期非常短。在警告刺激的初始视觉诱发电位之后，在双脑前额叶和运动前皮层的广泛区域记录到对命令性刺激的s-N、d-P持续慢电位。同侧小脑半球切除术对运动手的短潜伏期运动几乎没有影响，这与单纯反应时运动的情况有很大不同。这可能暗示，在警告命令刺激下，额叶联合皮层的持续活动可以在一定程度上克服小脑的缺陷。在对人类受试者的研究中，在同样的“走”/“不走”任务中，也记录了人类头皮的“不走”电位。它广泛分布于头皮前部，最大分布于顶点（Fz）。警告-必要刺激在人头皮上诱发偶然负变异（CNV）。额叶联想皮层的持续活动一定与对即将到来的刺激的精神集中有关。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