Neuroglia: gliosis and focal epilepsy.

Normal neuroglial cells buffer the extracellular space around neurons and presynaptic terminals against increases in potassium ions. Epileptic foci resulting from brain injury are characterized by areas of intense fibrillary gliosis bordering neuronal tissue. The known pathological changes that occur in gliosis may impair glial control of extracellular potassium ions and lead to excessively excitable neuronal border regions.