: In this work we discuss Hebb's old ideas about cell assemblies in the light of recent results concerning temporal structure and correlations in neural signals. We want to give a conceptual, necessarily only rough picture, how ideas about `binding by synchronisation', `synfire chains', `local and global assemblies', `short and long term memory' and `behaviour' might be integrated into a coherent model of brain functioning based on neuronal assemblies. Keywords: cell assemblies, synchronization, gamma-oscillations, synfire chains, memory, behaviour 1 ASSEMBLIES AND ASSOCIATIVE MEMORIES 1.1 Cell Assemblies Cell assemblies have been introduced by Donald Hebb with the intention of providing a functional and at the same time structural model for cortical processes and neuronal representations of external events (Hebb, 1949). According to Hebb's ideas, stimuli, objects, things, but also more abstract entities like concepts, contextual relations, ideas, and so on are thought of being repre...

This paper discusses the relation of theory and experiment in neuroscience exemplified by three assumptions often made in models of coherent activation in the cortex: basic feature-coding oscillators, phase-coding and global binding of whole objects. Apparently these assumptions are not very well supported by the experimental evidence. We propose that it is the single synchronized population-burst that matters: spikes of feature-coding cells are temporally clustered in our opinion by recurrent associative processes. In each burst a single stimulus is processed (if there are several). Synchronization is restricted to cortical sites which physically interact. These principles are illustrated by computer simulations.

We investigate the contribution of single cells to collective gamma-oscillations in a network of spiking neurons subject to an inhibitory activity control. In contrast to many earlier studies emphasizing a high precision in spike timing, cell ring is rather unreliable in our model. Nonetheless, we qualitatively reproduce many experimental ndings, some of them previously unexplored in modeling studies.