Trial manufacture of visual field specific stimulator by means of computer image frame memory and an application to brain metabolic mapping.

我们在这项研究项目中取得了两个主要成果：一是研制了一种视觉刺激器，并在电生理单单位记录中展示了其有效性。其次是将其应用于大脑的新陈代谢图谱。我们已经展示了在视觉记忆研究中使用“分形图”的优点。在本项目中，我们的视觉刺激器是通过修改FBX24(TEXNAI)图像帧存储系统来构建的。该刺激器利用FBX24的缩放、平移和滚动功能，成功地生成了分形图案，并在17毫秒内以任何大小呈现在视野的任何位置。通过使用该刺激器，我们发现在颞叶皮质中的形状选择神经活动对图像信息具有高度的选择性，并且与所呈现的刺激的大小、方向、颜色或位置等物理属性无关。在海马体中，我们发现神经元活动与显示刺激的位置有关。这一发现支持了海马体对位置记忆有贡献的假设。在第二次应用于脑代谢图谱中，采用2-脱氧葡萄糖放射自显影方法测量单侧视觉刺激后局部葡萄糖利用率(LGU)。我们发现，在视觉刺激过程中，小脑小叶，尤其是对侧的小脑小叶，表现出高LGU。在对侧小叶的中间1/3处，我们发现了斑片状的高LGU区域，可能与小脑微区相对应。在，东京大学医院引入了正电子发射断层扫描，放射科要求我们为正电子发射断层扫描系统改装我们的视觉刺激器。进一步发展我们的结果对于临床诊断是重要的。

We obtained two major results in this research project; first was to manufacture a visual stimulator and to show its effectiveness in an electrophysiological single-unit recording. Second was to apply it to the metabolic mapping of the brain.We had already shown merits of using "fractal patterns" in the research of visual memory. In this project our visual stimulator was constructed by modifying the FBX24 (Texnai) image frame memory system. The stimulator utilized the zoom, pan and scroll functions of FBX24 and succeeded in generating fractal patterns and presenting them at any position of the visual field in any size within 17msec. By using this stimulator we found that a shape-selective neural activity in the temporal cortex was highly selective for the pictorial information and was independent of the physical attributes such as size, orientation, color or position of the presented stimulus. In the hippocampus we found neuronal activity related to the place in which a stimulus was shown. This finding supports the hypothesis that the hippocampus contributes to the place memory. In the second application to metabolic mapping of the brain, local glucose utilization rates (LGU) were measured by 2-deoxyglucose autoradiography method after unilateral visual stimulation. We found that the cerebellar flocculus, especially in the contralateral side, exhibited high LGU during the visual stimulation. In the middle one-third of the contralateral flocculus we found patch-like high LGU areas, which may correspond to the cerebellar microzones.In 1989 a positron emission tomography (PET) was introduced in the Tokyo University Hospital and the Department of Radiology asked us to modify our visual stimulator for the PET system. It is important to further develop our results for a clinical diagnosis.