Spigler Giacomo, Wilson Stuart P
Sheffield Robotics, The University of Sheffield, Sheffield, United Kingdom.
Department of Psychology, The University of Sheffield, Sheffield, United Kingdom.
PLoS One. 2017 Jun 12;12(6):e0179306. doi: 10.1371/journal.pone.0179306. eCollection 2017.
Repetition suppression refers to a reduction in the cortical response to a novel stimulus that results from repeated presentation of the stimulus. We demonstrate repetition suppression in a well established computational model of cortical plasticity, according to which the relative strengths of lateral inhibitory interactions are modified by Hebbian learning. We present the model as an extension to the traditional account of repetition suppression offered by sharpening theory, which emphasises the contribution of afferent plasticity, by instead attributing the effect primarily to plasticity of intra-cortical circuitry. In support, repetition suppression is shown to emerge in simulations with plasticity enabled only in intra-cortical connections. We show in simulation how an extended 'inhibitory sharpening theory' can explain the disruption of repetition suppression reported in studies that include an intermediate phase of exposure to additional novel stimuli composed of features similar to those of the original stimulus. The model suggests a re-interpretation of repetition suppression as a manifestation of the process by which an initially distributed representation of a novel object becomes a more localist representation. Thus, inhibitory sharpening may constitute a more general process by which representation emerges from cortical re-organisation.
重复抑制是指由于对刺激的重复呈现而导致皮质对新刺激的反应减弱。我们在一个成熟的皮质可塑性计算模型中证明了重复抑制，根据该模型，侧向抑制相互作用的相对强度通过赫布学习进行修改。我们提出该模型是对由锐化理论提供的传统重复抑制解释的扩展，锐化理论强调传入可塑性的贡献，而我们则将这种效应主要归因于皮质内电路的可塑性。作为支持，在仅在皮质内连接启用可塑性的模拟中显示出重复抑制的出现。我们在模拟中展示了扩展的“抑制性锐化理论”如何解释在研究中报告的重复抑制的破坏，这些研究包括一个中间阶段，即暴露于由与原始刺激相似的特征组成的额外新刺激。该模型表明，重复抑制可重新解释为一个过程的表现，即一个新物体最初的分布式表征如何变成一个更加局部化的表征。因此，抑制性锐化可能构成一个更普遍的过程，通过该过程表征从皮质重组中出现。
