Lateral Spread of Orientation Selectivity in V1 is Controlled by Intracortical Cooperativity.
Lateral Spread of Orientation Selectivity in V1 is Controlled by Intracortical Cooperativity.
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DOI：
10.3389/fnsys.2011.00004
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发表时间：
2011
影响因子：
3
通讯作者：
Grinvald A
中科院分区：
文献类型：
--
作者：
Chavane F;Sharon D;Jancke D;Marre O;Frégnac Y;Grinvald A
初级视觉皮层中的神经元通过各种皮层连接接收来自其感受野 (RF) 外围的潜意识信息。据报道，在猫的初级视觉皮层中，长程水平轴突优先与具有相似方向偏好的远处柱结合，而来自更高视觉区域的反馈连接提供了更多样化的功能输入。为了理解这些横向相互作用的作用，表征它们的有效功能连接和调节特性至关重要。然而，无论其解剖学起源如何，皮质侧向连接的整体功能影响尚不清楚，因为它从未被直接表征过。通过直接测量猫区域 17 和 18 的突触后整合，我们对视觉驱动的横向网络的功能影响进行了多尺度评估。 电压敏感染料成像表明，局部定向刺激会引起定向选择性活动，该活动仍局限于刺激的皮质前馈印记。超过一根超柱的距离后，皮层活动的横向扩散逐渐失去其方向偏好，近似为指数，空间常数约为 1mm。 细胞内记录表明，这种方向选择性的丧失是由源自经典 RF 之外的会聚突触输入模式的多样性引起的。相反，当刺激大小增加时，我们观察到激活的方向选择性扩散超出了前馈印记。我们得出的结论是，刺激引起的协同性增强了远程方向选择性传播。
Neurons in the primary visual cortex receive subliminal information originating from the periphery of their receptive fields (RF) through a variety of cortical connections. In the cat primary visual cortex, long-range horizontal axons have been reported to preferentially bind to distant columns of similar orientation preferences, whereas feedback connections from higher visual areas provide a more diverse functional input. To understand the role of these lateral interactions, it is crucial to characterize their effective functional connectivity and tuning properties. However, the overall functional impact of cortical lateral connections, whatever their anatomical origin, is unknown since it has never been directly characterized. Using direct measurements of postsynaptic integration in cat areas 17 and 18, we performed multi-scale assessments of the functional impact of visually driven lateral networks. Voltage-sensitive dye imaging showed that local oriented stimuli evoke an orientation-selective activity that remains confined to the cortical feedforward imprint of the stimulus. Beyond a distance of one hypercolumn, the lateral spread of cortical activity gradually lost its orientation preference approximated as an exponential with a space constant of about 1 mm. Intracellular recordings showed that this loss of orientation selectivity arises from the diversity of converging synaptic input patterns originating from outside the classical RF. In contrast, when the stimulus size was increased, we observed orientation-selective spread of activation beyond the feedforward imprint. We conclude that stimulus-induced cooperativity enhances the long-range orientation-selective spread.