Tonic-clonic seizure transitions in a next generation neural field model #

Oliver Cattell

11:30 Tuesday in 2Q50/51.

Part of the Neurodynamics session.

Abstract #

Epilepsy is a dynamic complex disease involving a paroxysmal change in the activity of millions of neurons, often resulting in seizures. Tonic-clonic seizures are a particularly important class of seizures. Fast rhythmic spikes during the tonic stage are associated with muscle stiffness that give way to bursts and slow waves associated with muscle jerks during the clonic phase. This has previously been theorised to arise in systems with an instability from one temporal rhythm to another via a quasiperiodic transition. We show this is possible in a field version of a new class of neural mass model and that this can arise via a secondary instability of the homogeneous steady state. The bifurcation diagram for this scenario is constructed using a weakly nonlinear analysis beyond the point where two incommensurate temporal frequencies are excited. The model is derived from a network of spiking neurons with chemical and electrical synapses and reduces the description of many neurons to a small number of physically meaningful macroscopic variables (population firing rate, mean membrane potential and synchrony). This allows us to identify some key physiological mechanisms underlying the susceptibility of cortical tissue to tonic-clonic seizures.