Grossberg S, Williamson J R
Department of Cognitive and Neural Systems and Center for Adaptive Systems, Boston University, Boston, MA 02215, USA.
Cereb Cortex. 2001 Jan;11(1):37-58. doi: 10.1093/cercor/11.1.37.
A neural model suggests how horizontal and interlaminar connections in visual cortical areas V1 and V2 develop within a laminar cortical architecture and give rise to adult visual percepts. The model suggests how mechanisms that control cortical development in the infant lead to properties of adult cortical anatomy, neurophysiology and visual perception. The model clarifies how excitatory and inhibitory connections can develop stably by maintaining a balance between excitation and inhibition. The growth of long-range excitatory horizontal connections between layer 2/3 pyramidal cells is balanced against that of short-range disynaptic interneuronal connections. The growth of excitatory on-center connections from layer 6-to-4 is balanced against that of inhibitory interneuronal off-surround connections. These balanced connections interact via intracortical and intercortical feedback to realize properties of perceptual grouping, attention and perceptual learning in the adult, and help to explain the observed variability in the number and temporal distribution of spikes emitted by cortical neurons. The model replicates cortical point spread functions and psychophysical data on the strength of real and illusory contours. The on-center, off-surround layer 6-to-4 circuit enables top-down attentional signals from area V2 to modulate, or attentionally prime, layer 4 cells in area V1 without fully activating them. This modulatory circuit also enables adult perceptual learning within cortical area V1 and V2 to proceed in a stable way.
一种神经模型揭示了视觉皮层区域V1和V2中的水平连接和层间连接如何在层状皮层结构中发育，并产生成人的视觉感知。该模型表明，婴儿期控制皮层发育的机制如何导致成人皮层解剖结构、神经生理学和视觉感知的特性。该模型阐明了兴奋性和抑制性连接如何通过维持兴奋与抑制之间的平衡而稳定发育。第2/3层锥体细胞之间的长距离兴奋性水平连接的生长与短距离双突触中间神经元连接的生长保持平衡。从第6层到第4层的兴奋性中心连接的生长与抑制性中间神经元外周连接的生长保持平衡。这些平衡的连接通过皮层内和皮层间反馈相互作用，以实现成人感知分组、注意力和感知学习的特性，并有助于解释观察到的皮层神经元发放的尖峰数量和时间分布的变异性。该模型复制了皮层点扩散函数以及关于真实和虚幻轮廓强度的心理物理学数据。第6层到第4层的中心-外周回路使来自V2区域的自上而下的注意力信号能够调节V1区域第4层细胞，或对其进行注意力启动，而不会使其完全激活。这种调节性回路还使皮层区域V1和V2内的成人感知学习能够以稳定的方式进行。
