Multimodular Networks and Semantic Memory Impairments

We present a multi-modular approach to neural modeling of associative memory. By segregating between intra-modular and inter-modular synaptic transmission, and subjecting the latter to non-linear dendritic processing, we can successfully store memories encoded on different numbers of modules. This model has a striking capability of memory retrieval from partial inputs when the appropriate neurons in only few modules, or even a single module, are activated by afferent connections. Hence, if modular afferents are lesioned, memories that are encoded in more modules are more resilient to damage. Assuming that memories of concrete objects are encoded in a larger number of modules than abstract ones, our results provide a novel explanation of the phenomenon of category specific semantic impairments in patients with deep acquired dyslexia. D. H. 2 1 Introduction Imaging studies (Martin et al. 1995, Martin et al. 1996) support the notion that the knowledge of concrete objects is stored in ..