SPONTANEOUS EXCITATIONS IN THE VISUAL-CORTEX - STRIPES, SPIRALS, RINGS, AND COLLECTIVE BURSTS

As a simple model of the cortical sheet, we study a locally connected net of spiking neurons. Refractoriness, noise, axonal delays, and the time course of excitatory and inhibitory postsynaptic potentials are t aken into account explicitly. In addition to a low-activity state and depending on the synaptic efficacy, four different scenarios evolve sp ontaneously, viz., stripes, spirals, rings, and collective bursts. Our results can be related to experimental observations of drug-induced e pilepsy and hallucinations.