Why do infants have seizures?

Epidemiologic studies indicate that seizures occur more frequently early in life than in any other age group. To elucidate the ontogenetic substrates of seizure susceptibility, it is important to study the mechanisms of epileptogenesis in immature and mature animals. Developmental studies of experimental focal seizures using a variety of seizure models have suggested that young animals have unique behavioral seizure patterns, including the presence of bilateral although asymmetric convulsions. There are differences in the mechanisms responsible for the generation of seizures, propagation patterns and seizure arrest and recurrences. These include maturational differences at the neuronal level or local circuits as well as in the functional activity of systems responsible in part for the control of seizures in adulthood. One such system involves the substantia nigra and its output connections. Data will be presented demonstrating how evolving neurobiologic processes modulate the expression of seizures as a function of age. Understanding of the age-related differences is important for the development of new antiepileptic treatments to effectively control age- specific seizure disorders.