A study of decision processes for motion discrimination

本研究旨在探讨视觉运动方向感知和决策过程的脑机制。为了实现这一目标，我们使用了两种方法。在日本，当猴子（恒河猴）执行视觉运动的感知和决策任务时，我们使用功能成像技术来绘制整个大脑的激活区域。我们使用了滨松音响公司的PET机器，这是专门为动物设计的。为了开发移动随机点的计算机程序和训练猴子，斯坦福大学纽森教授实验室的工作人员来到日本，帮助日本团队。我们还在日本开了3次讨论会，在美国开了5次讨论会，设计项目，讨论PET研究的结果。在美国，Newsome使用了不同的方法来研究视觉运动的大脑机制——记录单个神经元的活动。他和他的工作人员将微电极引入顶叶皮层，以确定行为猴子在视觉感知和决策过程中的神经元活动特征。他们从顶叶联合皮层开始记录，因为我们在初步的PET研究中发现顶叶皮层在视觉运动任务中是活跃的。他们发现神经元活动与决策过程有关。因此，日本和美国之间的确证工作非常有效，在两个实验室进行的研究都是富有成效的。

The objective of this research is to investigate brain mechanism underling perception and decision making process of the direction of visual motion. In order to achieve this objectiv, we used 2 approaches. In Japan, we used the functional imaging technique to map the activated areas of the whole brain while the monkey (rhesus monkey) is performing the perception and decision task of visual motion. We used the PET machine in Hamamatsu Phononics which is specially designed for animal use. To develop the computer program of moving random dots and to train monkeys, staffs of Professor Newsomels laboratory in the Stanford University came to Japan and help Japanese teem. We also had the discussion meeting 3 times in Japan and 5 times in the United States to design the project and to discuss the results of the PET study. In the United States, Newsome used the different approach to investigate the brain mechanisms of visual motion --recording of single neuronal activities. He and his staffs introduced micro-electrode into the parietal cortex to determine the characteristics of neuronal activities during the visual perception and decision process of behaving monkeys. They started recording from the parietal association cortex, since we found in our preliminary PET study that the parietal cortex is active during the visual motion task. They found that neuronal activity related decision process. Thus the corroboration between Japan and the United States worked very effciently and researches performed in both laboratory was productive.