Effects of seizures on brain development: lessons from the laboratory.

Both clinical and laboratory studies demonstrate that seizures early in life can result in permanent behavioral abnormalities and enhance epileptogenicity. In experimental rodent models, the consequences of seizures are dependent upon age, etiology, seizure duration, and frequency. Recurrent seizures in immature rats result in long-term adverse effects on learning and memory. These behavioral changes are paralleled by changes in brain connectivity, dendritic morphology, excitatory and inhibitory receptor subunits, ion channels, and neurogenesis. These changes can occur in the absence of cell loss. Although impaired cognitive function and brain changes have been well documented after early onset seizures, the mechanisms of seizure-induced injury remain unclear. Recent studies have demonstrated abnormalities in single cell function that parallel behavioral changes.