FUNCTIONAL ANATOMY OF PERCEPTUAL AND MEMORY SYSTEMS IN THE PRIMATE BRAIN

为了更好地理解皮层调节感知和记忆的机制，我们一直在研究由非人类灵长类动物视觉关联皮层组成的功能区，并利用神经解剖学追踪技术结合神经活动的生理记录来探索它们之间的相互联系。我们的研究结果表明，在信息处理过程中，在初级视觉皮层之外存在着多种独立的视觉区域。这些区域形成了两个层次组织和功能专门化的皮质通路：一个枕颞通路，或腹侧流，用于识别物体；一个枕顶叶通路，或背侧流，用于欣赏物体之间的空间关系和向它们移动的视觉引导。位于颞叶通路沿线区域的神经元处理物体的视觉特征，如颜色和形状，而位于顶叶通路沿线区域的神经元处理物体的视觉空间属性，如运动方向。这两种处理途径不仅在解剖学和功能上是不同的，而且还可以通过它们的神经化学特征来区分。枕顶通路中的绝大多数神经元含有神经丝蛋白，而枕颞通路中只有不到一半的神经元含有神经丝蛋白。为了确定人类和猴子大脑之间的同源性，我们已经开始使用功能性脑成像对人类受试者进行研究，并使用与我们在猴子脑组织上使用的相同的免疫组织学染色技术对人类脑组织进行研究。到目前为止，在我们的脑成像研究中，我们已经定位了人类大脑中的两种视觉处理途径，研究了它们内部视觉属性的功能专门化，并确定了它们在前额叶皮层中对工作记忆的进一步扩展。此外，我们已经证明，简单技能的学习和保留，无论是知觉的还是运动的，都涉及到皮层处理的非常早期阶段的神经机制，即初级视觉和运动皮层。在我们对人类脑组织的研究中，我们已经成功地确定了人类大脑中的几个皮层区域，这些区域已经在猴子的大脑中被描述过，包括视觉区域V2、V3和MT。未来的研究将继续对人类的感知和记忆进行功能性脑成像研究，并对清醒、有行为的猴子进行平行的单细胞记录研究。一个主要的努力将是确定注意力和记忆的自上而下的影响如何影响知觉加工。-视觉认知，脑成像，大脑皮层，感知，记忆，运动学习-人类受试者

To better understand the cortical mechanisms mediating perception and memory, we have been examining the functional areas that comprise visual association cortex in nonhuman primates and explored their interconnections by the use of neuroanatomical tracing techniques in combination with physiological recording of neural activity. Our results indicate that a multiplicity of separate visual areas lie beyond the primary visual cortex in the stream of information processing. These areas form two hierarchically organized and functionally specialized cortical pathways: an occipitotemporal pathway, or ventral stream, for the identification of objects, and an occipitoparietal pathway, or dorsal stream, for the appreciation of the spatial relationships among objects and the visual guidance of movement towards them. Whereas neurons in the areas along the pathway into the temporal lobe process the visual features objects, such as color and form, those in areas along the pathway into the parietal lobe process the visuospatial attributes of objects, such as their direction of motion. Not only are the two processing pathways anatomically and functionally distinct, but they can also be differentiated by their neurochemical profiles. Whereas the vast majority of neurons within the occipitoparietal pathway contain neurofilament protein, this is true for less than half the neurons within the occipitotemporal pathway. In an attempt to identify homologies between the human and monkey brains, we have begun investigations of human subjects using functional brain imaging and of human brain tissue using the same immunohistological staining techniques that we have used on monkey brain tissue. Thus far in our brain imaging studies, we have localized the two visual processing pathways within the human brain, investigated functional specialization of visual attributes within them, and identified their further extensions for working memory in the prefrontal cortex. Additionally, we have demonstrated that the learning and retention of simple skills, both perceptual and motor, involves neural mechanisms located at very early stages of cortical processing, namely, the primary visual and motor cortex. In our work with human brain tissue, we have successfully identified several cortical areas in the human brain that have been described in the monkey brain, including visual areas V2, V3 and MT. Future studies will pursue functional brain imaging studies of perception and memory in humans and parallel single- cell recording studies in awake, behaving monkeys. A major effort will be to determine how top- down influences of attention and memory affect perceptual processing. - visual cognition, brain imaging, cerebral cortex, perception, memory, motor learning - Human Subjects