Cortical and perceptual processing of naturalistic visualstructure
自然图像在大脑中的信息处理
主办方：北京师范大学脑与认知科学研究院
认知神经科学与学习国家重点实验室
主讲人：Prof. J. Anthony Movshon
时间：2014年9月16日上午10点
地点：北京师范大学
图书馆一层会议室
Joseph Anthony Movshon, Ph.D., Professor
Member, National Academy of Sciences
Fellow, American Academy of Arts and Sciences
Director, Center for Neural Science, New York University
美国科学院院士 Tony Movshon 博士是资深的视觉科学家，是美国纽约大学神经科学中心的终身教授。他于1975年在英国剑桥大学获得博士学位，随后加入纽约大学任助理教授、1984年获终身教授、并担任神经科学中心的主任，2002年成为Silver荣誉教授，2008年当选为美国科学院院士。他担任过认知神经科学协会（CNS）和视觉科学协会（VSS）的主席。Movshon 博士的主要研究涉及视觉的多个领域，包括中枢视觉系统的生理和形态、空间和运动视觉的心理物理研究、视觉发育、计算神经科学等。
The perception of complex visual patterns emerges from neuronal activity in a cascade of areas in the primate cerebral cortex. Neurons in the primary visual cortex (V1) represent information about local orientation and spatial scale,but the role of the second visual area (V2) is enigmatic. We made synthetic images that contain complex features found in naturally occurring visual textures, and used them to stimulate macaque V1 and V2 neurons. Most V2 cells respond more vigorously to these stimuli than to matched control stimuli lacking naturalistic structure, while V1 cells do not. fMRI measurements in humans reveal differences in V1 and V2 responses to the same textures that are consistent with neuronal measurements in macaque. The ability of human observers to detect naturalistic structure is well predicted by the strength of the neuronal and fMRI responses in V2 but not in V1.
Preliminary results suggest a further transformation of information downstream of V2, in which the representation of natural scenes becomes a more prominent driving feature of cortex. These results reveal a particular role for V2 in there presentation of naturally occurring structure in visual images, and suggest ways that it begins the transformation of information about elementary visual features into the specific signals about scenes and objects that are found in areas further downstream in the visual pathway.
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