A layered neural continuum architecture in attention and seizure disorders

Neural continuum theory concerns regions containing large numbers of neurons. Connections within a region are not specified and those between regions are probabilistic. Constituent cells can be treated as purely "excitatory" or "inhibitory." In a layered geometry, with a time delay between layers, delay is the variable controlling the linear behavior of the system, in particular, growth of small disturbances. Two layers of cells of opposite types structurally resemble and functionally model the attention centers of the brain (the reticular formation). Attention shifts among competing regions through changes in local inhibitory time waves and their spatial propagation. Increase in delay above a critical value, leads to large amplitude, spatially uniform activity; non-linear extension of the two-layer model predicts potentials in qualitative agreement with those observed during seizures. The preferentially amplified spatial-frequency of normal waves remains relatively constant with delay. Since it is proportional to the locally varying mean lateral axonal extent, spatial-frequency is a signature by which the most compelling region can be recognized by higher brain centers.