McManus Justin N J, Ullman Shimon, Gilbert Charles D
Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
J Neurophysiol. 2008 May;99(5):2086-100. doi: 10.1152/jn.00871.2007. Epub 2008 Jan 16.
The ablation of afferent input results in the reorganization of sensory and motor cortices. In the primary visual cortex (V1), binocular retinal lesions deprive a corresponding cortical region [lesion projection zone (LPZ)] of visual input. Nevertheless, neurons in the LPZ regain responsiveness by shifting their receptive fields (RFs) outside the retinal lesions; this re-emergence of neural activity is paralleled by the perceptual completion of disrupted visual input in human subjects with retinal damage. To determine whether V1 reorganization can account for perceptual fill-in, we developed a neural network model that simulates the cortical remapping in V1. The model shows that RF shifts mediated by the plexus of spatial- and orientation-dependent horizontal connections in V1 can engender filling-in that is both robust and consistent with psychophysical reports of perceptual completion. Our model suggests that V1 reorganization may underlie perceptual fill-in, and it predicts spatial relationships between the original and remapped RFs that can be tested experimentally. More generally, it provides a general explanation for adaptive functional changes following CNS lesions, based on the recruitment of existing cortical connections that are involved in normal integrative mechanisms.
传入输入的消融会导致感觉和运动皮层的重组。在初级视觉皮层（V1）中，双眼视网膜损伤会使相应的皮层区域[损伤投射区（LPZ）]失去视觉输入。然而，LPZ中的神经元通过将其感受野（RFs）转移到视网膜损伤区域之外而重新获得反应性；这种神经活动的重新出现与视网膜损伤的人类受试者中视觉输入中断的感知完成相平行。为了确定V1重组是否可以解释感知填补，我们开发了一个神经网络模型来模拟V1中的皮层重新映射。该模型表明，由V1中空间和方向依赖性水平连接丛介导的RF转移可以产生既稳健又与感知完成的心理物理学报告一致的填补。我们的模型表明，V1重组可能是感知填补的基础，并且它预测了可以通过实验测试的原始RF和重新映射的RF之间的空间关系。更一般地说，它基于参与正常整合机制的现有皮层连接的募集，为中枢神经系统损伤后的适应性功能变化提供了一个一般性解释。
