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PubMed2006

Effects of distributed transmission speeds on propagating activity in neural populations.

Motivated by experimental evidence, a distribution of axonal transmission speeds is introduced into a standard field model of neural populations. The resulting field dynamics is analytically studied by a systematic investigation of the stability and bifurcations of equilibrium solutions. Using a perturbation approach, the effect of distributed speeds on bifurcations of equilibria are determined for general connectivity and speed distributions. In addition, a nonlinear analysis of traveling fronts is given. It is shown that the variance of the speed distribution affects the frequency of bifurcating periodic solutions and the phase speed of traveling waves. Moreover, a new effect is discovered where the introduction of axonal speed distributions leads to the maximization of the traveling front speed.

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PubMed2003

Pattern formation in intracortical neuronal fields.

This paper introduces a neuronal field model for both excitatory and inhibitory connections. A single integro-differential equation with delay is derived and studied at a critical point by stability analysis, which yields conditions for static periodic patterns and wave instabilities. It turns out that waves only occur below a certain threshold of the activity propagation velocity. An additional brief study exhibits increasing phase velocities of waves with decreasing slope subject to increasing activity propagation velocities, which are in accordance with experimental results. Numerical studies near and far from instability onset supplement the work.

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