Spike-rate adaptation and neuronal bursting in a mean-field model of brain activity.
Spike-rate adaptation is investigated within a mean-field model of brain activity. Two different mechanisms of negative feedback are considered; one involving modulation of the mean firing threshold, and the other, modulation of the mean synaptic strength. Adaptation to a constant stimulus is shown to take place for both mechanisms, and limit-cycle oscillations in the firing rate corresponding to bursts of neuronal activity are investigated. These oscillations are found to result from a Hopf bifurcation when the equilibrium lies between the local maximum and local minimum of a given nullcline. Oscillations with amplitudes significantly below the maximum firing rate are found over a narrow range of possible equilibriums.
Loxley
P N
PN
School of Physics, The University of Sydney, Sydney, NSW 2006, Australia. loxley@physics.usyd.edu.au
Robinson
P A
PA
D000200:Action Potentials / Q000502:physiology*; D000222:Adaptation, Physiological / Q000502:physiology; D000465:Algorithms; D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D001921:Brain / Q000502:physiology*; D002540:Cerebral Cortex / Q000502:physiology; D003198:Computer Simulation; D005071:Evoked Potentials / Q000502:physiology; D005246:Feedback / Q000502:physiology; D006801:Humans; D009415:Nerve Net / Q000502:physiology*; D016571:Neural Networks, Computer; D009434:Neural Pathways / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D013788:Thalamus / Q000502:physiology