Neurophysiology, neuropharmacology and behavioral relationships of visual system evoked after-discharges: A review

Visually evoked response (VER) after-discharge (AD) research is reviewed. Neurophysiological and neuroanatomical contributions are developed in terms of the thalamic generating mechanisms of VER ADs, with specific reference to the dorsal lateral geniculate nucleus. The association between a variety of brain systems including the mesencephalic reticular formation, superior colliculus, ventral lateral geniculate nucleus, pulvinar, hippocampus and medial geniculate in terms of the modulation and functional significance of the VER AD is provided. The neuropharmacology of VER ADs is likewise examined with respect to the development of an experimental epilepsy model, this being dependent upon the observations that convulsants markedly augment while anticonvulsants significantly attenuate VER ADs. Cholinergic and catecholaminergic systems are also discussed in terms of their relevancy with the neuropharmacology of VER ADs. A variety of behavioral relationships have been determined and are likewise reviewed. A unifying theme of the behavioral research associated with VER AD elicitation and elaboration has been with an underlying arousal dimension. The multidisciplinary approach taken by VER AD research suggests the direct application of this type of orientation for a variety of behavioral research areas.