Raffone A, Wolters G
La Sapienza University of Rome.
J Cogn Neurosci. 2001 Aug 15;13(6):766-85. doi: 10.1162/08989290152541430.
Luck and Vogel (1997) showed that the storage capacity of visual working memory is about four objects and that this capacity does not depend on the number of features making up the objects. Thus, visual working memory seems to process integrated objects rather than individual features, just as verbal working memory handles higher-order "chunks" instead of individual features or letters. In this article, we present a model based on synchronization and desynchronization of reverberatory neural assemblies, which can parsimoniously account for both the limited capacity of visual working memory, and for the temporary binding of multiple assemblies into a single pattern. A critical capacity of about three to four independent patterns showed up in our simulations, consistent with the results of Luck and Vogel. The same desynchronizing mechanism optimizing phase segregation between assemblies coding for separate features or multifeature objects poses a limit to the number of oscillatory reverberations. We show how retention of multiple features as visual chunks (feature conjunctions or objects) in terms of synchronized reverberatory assemblies may be achieved with and without long-term memory guidance.
勒克和沃格尔（1997年）表明，视觉工作记忆的存储容量约为四个物体，且这一容量并不取决于构成物体的特征数量。因此，视觉工作记忆似乎处理的是整合后的物体而非单个特征，就如同言语工作记忆处理的是高阶“组块”而非单个特征或字母一样。在本文中，我们提出了一个基于回响神经集合的同步和去同步的模型，该模型能够简洁地解释视觉工作记忆的有限容量，以及多个集合临时绑定成单一模式的现象。在我们的模拟中出现了约三到四个独立模式的关键容量，这与勒克和沃格尔的结果一致。在为单独特征或多特征物体编码的集合之间优化相位分离的相同去同步机制，对振荡回响的数量构成了限制。我们展示了在有和没有长期记忆引导的情况下，如何通过同步的回响集合将多个特征作为视觉组块（特征结合或物体）进行保留。
