1. Population dynamics: variance and the sigmoid activation function.
- Author
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Marreiros AC, Daunizeau J, Kiebel SJ, and Friston KJ
- Subjects
- Algorithms, Computer Simulation, Humans, Models, Statistical, Statistical Distributions, Brain physiology, Brain Mapping methods, Electroencephalography methods, Evoked Potentials physiology, Models, Neurological
- Abstract
This paper demonstrates how the sigmoid activation function of neural-mass models can be understood in terms of the variance or dispersion of neuronal states. We use this relationship to estimate the probability density on hidden neuronal states, using non-invasive electrophysiological (EEG) measures and dynamic casual modelling. The importance of implicit variance in neuronal states for neural-mass models of cortical dynamics is illustrated using both synthetic data and real EEG measurements of sensory evoked responses.
- Published
- 2008
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