The role of seizure-induced neurogenesis in epileptogenesis and brain repair.

Data accumulated over the past four decades have led to the widespread recognition that neurogenesis, the birth of new neurons, persists in the hippocampal dentate gyrus and rostral forebrain subventricular zone (SVZ) of the adult mammalian brain. Neural precursor cells located more caudally in the forebrain SVZ are thought to also give rise to glia throughout life. The continued production of neurons and glia suggests that the mature brain maintains an even greater potential for plasticity after injury than was previously recognized. Underscoring this idea are recent findings that seizures induced by various experimental manipulations increase neurogenesis in the adult rodent dentate gyrus. Although neurogenesis and gliogenesis in persistent germinative zones are altered in adult rodent models of temporal lobe epilepsy (TLE), the effects of seizure-induced neurogenesis in the epileptic brain, in terms of either a pathological or reparative role, are only beginning to be explored. Emerging data suggest that altered neurogenesis in the epileptic dentate gyrus may be pathological and promote abnormal hyperexcitability. However, the presence of endogenous neural progenitors in other proliferative regions may offer potential strategies for the development of anti-epileptogenic or neuronal replacement therapies.