Simulated Electrocortical Activity at Microscopic, Mesoscopic and Global Scales

Australian Journal of Psychology, Volume 55, 2003.
International Journal of Bifurcation, Volume 14, Issue 2, pp 853-872, 2004, Doi: 10.1142/S0218127404009569.
Neuropsychopharmacology, Volume 28, pp S80-S90, 2003, Doi: 10.1038/sj.npp.1300138.

J.J. WRIGHT1,2,3,6, C.J. RENNIE1,4,5, G.J. LEES3, P.A. ROBINSON1,4,

1. Brain Dynamics Centre, Westmead Hospital and University of Sydney, Westmead, NSW 2145, Australia.

2. Mental Health Research Institute, Parkville, Victoria 3052, Australia.

3. Department of Psychiatry, University of Auckland School of Medicine, Auckland, New Zealand.

4. Theoretical Physics Group, School of Physics, University of Sydney, NSW 2006, Australia.

5. Department of Medical Physics, Westmead Hospital, Westmead, NSW 2145, Australia.

6. Liggins Institute, University of Auckland, Auckland, New Zealand.

7. Department of Psychological Medicine, Westmead Hospital and University of Sydney, Westmead, NSW 2145, Australia.


Simulation of electrocortical activity requires (a) determination of the most crucial features to be modelled, (b) specification of state equations with parameters that can be determined against independent measurements, and (c) explanation of electrical events in the brain at several scales. We report our attempts to address these problems, and show that mutually consistent explanations, and simulation of experimental data can be achieved for cortical gamma activity, synchronous oscillation, and the main features of the EEG power spectrum including the cerebral rhythms and evoked potentials. These simulations include consideration of dendritic and synaptic dynamics, AMPA, NMDA, and GABA receptors, and intracortical and cortical/subcortical interactions. We speculate on the way in which Hebbian learning and intrinsic reinforcement processes might complement the brain dynamics thus explained, to produce elementary cognitive operations.