Computational Physiology Laboratory, Cornell University Ithaca, NY, USA.
Front Integr Neurosci. 2012 Feb 10;6:5. doi: 10.3389/fnint.2012.00005. eCollection 2012.
Classical lateral inhibition, which relies on spatially ordered neural representations of physical stimuli, cannot decorrelate sensory representations in which stimulus properties are represented non-topographically. Recent theoretical and experimental studies indicate that such a non-topographical representation of olfactory stimuli predominates in olfactory bulb, thereby refuting the classical view that olfactory decorrelation is mediated by lateral inhibition comparable to that in the retina. Questions persist, however, regarding how well non-topographical decorrelation models can replicate the inhibitory "surround" that has been observed experimentally (with respect to odor feature-similarity) in olfactory bulb principal neurons, analogous to the spatial inhibitory surround generated by lateral inhibition in retina. Using two contrasting scenarios of stimulus representation - one "retinotopically" organized and one in which receptive fields are unpredictably distributed as they are in olfactory bulb - we here show that intracolumnar inhibitory interactions between local interneurons and principal neurons successfully decorrelate similar sensory representations irrespective of the scenario of representation. In contrast, lateral inhibitory interactions between these same neurons in neighboring columns are only able to effectively decorrelate topographically organized representations. While anatomical substrates superficially consistent with both types of inhibition exist in olfactory bulb, of the two only local intraglomerular inhibition suffices to mediate olfactory decorrelation.
经典的侧抑制依赖于物理刺激的空间有序的神经表示，而不能去相关化刺激属性非拓扑表示的感觉表示。最近的理论和实验研究表明，这种嗅觉刺激的非拓扑表示在嗅球中占主导地位，从而反驳了经典观点，即嗅觉去相关是通过与视网膜中类似的侧抑制来介导的。然而，关于非拓扑去相关模型在多大程度上可以复制嗅球主神经元中已经观察到的实验抑制“周围”（关于气味特征相似性）的问题仍然存在，类似于由视网膜中的侧抑制产生的空间抑制周围。使用两种对比的刺激表示场景——一种是“视网膜”组织的，另一种是在嗅球中感受野随机分布的——我们在这里表明，局部中间神经元和主神经元之间的柱内抑制相互作用可以成功地去相关相似的感觉表示，而与表示场景无关。相比之下，这些相同神经元在相邻柱之间的侧抑制相互作用仅能够有效地去相关拓扑组织的表示。虽然嗅球中存在与这两种抑制都表面上一致的解剖学基质，但只有局部的球内抑制足以介导嗅觉去相关。
