A continuum model of activity waves in layered neuronal networks: A neuropsychology of brainstem seizures

We model and brainstem as two layers of respectively purely excitatory and purely inhibitory cells, with instantaneous synaptic interactions within a layer, but with a variable time delay between the layers. For appropriate values of the connection parameters, this configuration provides an attentional mechanism. As the inhibitory delay increases, input signals are, at first, increasingly amplified and confined spatially. At larger delays, the amplified activity propagates into other regions allowing for spatial summation. The temporal frequency of the amplified activity decreases with increasing delay, but its spatial frequency remains relatively constant. As the delay increases through a critical region, a new regime is reached in which highly amplified activity occurs simultaneously over large areas. This regime exhibits many properties of seizure activity.