Antolík Ján
Unité de Neurosciences, Information et Complexité, Centre National de la Recherche Scientifique UPR 3293Gif-sur-Yvette, France.
Front Neural Circuits. 2017 Mar 31;11:21. doi: 10.3389/fncir.2017.00021. eCollection 2017.
Competitive interactions are believed to underlie many types of cortical processing, ranging from memory formation, attention and development of cortical functional organization (e.g., development of orientation maps in primary visual cortex). In the latter case, the competitive interactions happen along the cortical surface, with local populations of neurons reinforcing each other, while competing with those displaced more distally. This specific configuration of lateral interactions is however in stark contrast with the known properties of the anatomical substrate, i.e., excitatory connections (mediating reinforcement) having longer reach than inhibitory ones (mediating competition). No satisfactory biologically plausible resolution of this conflict between anatomical measures, and assumed cortical function has been proposed. Recently a specific pattern of delays between different types of neurons in cat cortex has been discovered, where direct mono-synaptic excitation has approximately the same delay, as the combined delays of the disynaptic inhibitory interactions between excitatory neurons (i.e., the sum of delays from excitatory to inhibitory and from inhibitory to excitatory neurons). Here we show that this specific pattern of delays represents a biologically plausible explanation for how short-range inhibition can support competitive interactions that underlie the development of orientation maps in primary visual cortex. We demonstrate this statement analytically under simplifying conditions, and subsequently show using network simulations that development of orientation maps is preserved when long-range excitation, direct inhibitory to inhibitory interactions, and moderate inequality in the delays between excitatory and inhibitory pathways is added.
竞争性相互作用被认为是许多类型皮质处理过程的基础，范围从记忆形成、注意力到皮质功能组织的发育（例如，初级视觉皮质中方位图的发育）。在后一种情况下，竞争性相互作用沿着皮质表面发生，局部神经元群体相互加强，同时与更远端移位的神经元群体竞争。然而，这种横向相互作用的特定配置与解剖学基质的已知特性形成鲜明对比，即兴奋性连接（介导加强作用）的作用范围比抑制性连接（介导竞争）更长。尚未提出关于解剖学测量与假定的皮质功能之间这种冲突的令人满意的生物学上合理的解决方案。最近，在猫皮质中发现了不同类型神经元之间的一种特定延迟模式，其中直接单突触兴奋的延迟与兴奋性神经元之间双突触抑制相互作用的组合延迟大致相同（即从兴奋性神经元到抑制性神经元以及从抑制性神经元到兴奋性神经元的延迟之和）。在这里，我们表明这种特定的延迟模式为短程抑制如何支持初级视觉皮质中方位图发育所基于的竞争性相互作用提供了一种生物学上合理的解释。我们在简化条件下通过分析证明了这一说法，随后使用网络模拟表明，当添加长程兴奋、直接抑制性到抑制性相互作用以及兴奋性和抑制性通路之间延迟的适度不平等时，方位图的发育得以保留。
