Miconi Thomas, Vanrullen Rufin
Centre de Recherche Cerveau et Cognition, Université de Toulouse, Université Paul Sabatier Toulouse, France.
Front Hum Neurosci. 2010 Nov 17;4:205. doi: 10.3389/fnhum.2010.00205. eCollection 2010.
While recent studies have shed light on the mechanisms that generate gamma (>40 Hz) oscillations, the functional role of these oscillations is still debated. Here we suggest that the purported mechanism of gamma oscillations (feedback inhibition from local interneurons), coupled with lateral connections implementing "Gestalt" principles of object integration, naturally leads to a decomposition of the visual input into object-based "perceptual cycles," in which neuron populations representing different objects within the scene will tend to fire at successive cycles of the local gamma oscillation. We describe a simple model of V1 in which such perceptual cycles emerge automatically from the interaction between lateral excitatory connections (linking oriented cells falling along a continuous contour) and fast feedback inhibition (implementing competitive firing and gamma oscillations). Despite its extreme simplicity, the model spontaneously gives rise to perceptual cycles even when faced with natural images. The robustness of the system to parameter variation and to image complexity, together with the paucity of assumptions built in the model, support the hypothesis that perceptual cycles occur in natural vision.
虽然最近的研究已经阐明了产生伽马（>40赫兹）振荡的机制，但这些振荡的功能作用仍存在争议。在这里，我们认为，所谓的伽马振荡机制（来自局部中间神经元的反馈抑制），与实施物体整合“格式塔”原则的侧向连接相结合，自然会导致视觉输入分解为基于物体的“感知周期”，其中代表场景中不同物体的神经元群体将倾向于在局部伽马振荡的连续周期中放电。我们描述了一个初级视觉皮层的简单模型，在该模型中，这种感知周期从侧向兴奋性连接（连接沿连续轮廓排列的定向细胞）和快速反馈抑制（实施竞争性放电和伽马振荡）之间的相互作用中自动出现。尽管该模型极其简单，但即使面对自然图像，它也能自发地产生感知周期。该系统对参数变化和图像复杂性的鲁棒性，以及模型中假设的匮乏，支持了感知周期发生在自然视觉中的假设。
