FUNCTIONAL ANATOMY OF PERCEPTUAL AND MEMORY SYSTEMS IN THE PRIMATE BRAIN

为了更好地了解大脑皮层调节感知和记忆的机制，我们一直在研究非人灵长类动物视觉关联皮层的功能区，并通过使用神经解剖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，在信息处理流中，初级视皮层之外存在着许多独立的视觉区域。这些区域形成了两个等级组织和功能特化的皮层通路：枕颞通路或腹侧流，用于识别物体，枕顶通路或背侧流，用于欣赏物体之间的空间关系和视觉引导运动。位于沿着通路进入颞叶的区域中的神经元处理物体的视觉特征，如颜色和形状，而位于沿着通路进入顶叶的区域中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不同，而且还可以通过其神经化学特征来区分。虽然绝大多数的神经元内的枕顶通路含有神经丝蛋白，这是真正的不到一半的神经元内的枕颞通路。在试图确定人类和猴子的大脑之间的同源性，我们已经开始调查人类受试者使用功能性脑成像和人类的脑组织使用相同的免疫组织学染色技术，我们已经在猴子的脑组织。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个视觉处理通路，研究了它们内部视觉属性的功能特化，并确定了它们在前额叶皮层中对工作记忆的进一步延伸。此外，我们已经证明，学习和保持简单的技能，知觉和运动，涉及神经机制位于非常早期阶段的皮层处理，即初级视觉和运动皮层。在我们对人脑组织的研究中，我们成功地识别出了几个在猴脑中描述过的人脑皮层区域，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处理。- 视觉认知，脑成像，大脑皮层，知觉，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