Intracortical vs. thalamocortical processing of spatial working memory

Working memory processes contain not only maintenance but manipulation of the working memory contents. The system of the mediodorsal (MD) nucleus and the prefrontal cortex is considered to contribute to some aspects of the working memory processes. This article studies computationally the characteristics of the integrated cortical and thalamocortical system. The model circuit is operated in the "thalamocortical mode", in which the thalamocortical inputs can control the cortical working memory representation. Our simulation shows that transient excitatory inputs to the MD relay cells can erase the working memory representation through the intracortical processes, especially the cross-directional inhibition. (C) 2003 Elsevier Science B.V. All rights reserved.