Baker Tanya I, Issa Naoum P
Department of Physics, University of Chicago, Chicago, Illinois 60637, USA.
J Neurophysiol. 2005 Jul;94(1):775-87. doi: 10.1152/jn.01093.2004. Epub 2005 Mar 9.
In the earliest cortical stages of visual processing, a scene is represented in different functional domains selective for specific features. Maps of orientation and spatial frequency preference have been described in the primary visual cortex using simple sinusoidal grating stimuli. However, recent imaging experiments suggest that the maps of these two spatial parameters are not sufficient to describe patterns of activity in different orientation domains generated in response to complex, moving stimuli. A model of cortical organization is presented in which cortical temporal frequency tuning is superimposed on the maps of orientation and spatial frequency tuning. The maps of these three tuning properties are sufficient to describe the activity in orientation domains that have been measured in response to drifting complex images. The model also makes specific predictions about how moving images are represented in different spatial frequency domains. These results suggest that the tangential organization of primary visual cortex can be described by a set of maps of separable neuronal receptive field features including maps of orientation, spatial frequency, and temporal frequency tuning properties.
在视觉处理的最早皮层阶段,一个场景在对特定特征具有选择性的不同功能域中得到表征。使用简单的正弦光栅刺激,已经在初级视觉皮层中描述了方向和空间频率偏好图谱。然而,最近的成像实验表明,这两个空间参数的图谱不足以描述响应复杂移动刺激而在不同方向域中产生的活动模式。本文提出了一种皮层组织模型,其中皮层时间频率调谐叠加在方向和空间频率调谐图谱之上。这三种调谐特性的图谱足以描述响应漂移复杂图像而测量到的方向域中的活动。该模型还对移动图像在不同空间频率域中的表征方式做出了具体预测。这些结果表明,初级视觉皮层的切向组织可以通过一组可分离的神经元感受野特征图谱来描述,包括方向、空间频率和时间频率调谐特性图谱。