Cell assemblies in the neocortex

Erik Fransen

Dept. of Numerical Analysis and Computer Science, Royal Institute of Technology,
S-100 44 Stockholm, Sweden

Abstract: The cell assembly is a conceptual entity introduced by D. O. Hebb in his classic book The organization of behavior. Within this book, Hebb described how the cell assembly would be formed, and how it could support internal representations of entities in the surrounding world. He also discussed associations between assemblies and sequences of such, as elements of "thought". The hypothesis has been adopted and extended by many. We have studied how this qualitative hypothesis could be formulated in a quantitative computational framework. We have also investigated its support from modern neuroscience in terms of structure and function. In a biophysical model, we have tested the performance for the assembly functions, as well as other computational variables such as speed of recall, unit activity levels, and flexibility of operation. In the presentation, the possibility that assembly-like operations may be present in multiple regions of the cortex, including its relations to the long-term and working memory function attributed to these regions, will also be discussed.