Commentary on Hewapathirane et al. (in vivo imaging of seizure activity in a novel developmental seizure model) seizure-induced brain damage: from tadpoles to children.

0014-4886/$ – see front matter © 2008 Elsevier Inc. Al doi:10.1016/j.expneurol.2008.05.005 Epilepsy, a condition characterized by repeated, unprovoked seizures, is unfortunately quite common, affecting approximately 1% of the population (Hauser, 1994), Epilepsy is most common in the first year of life and approximately 75% of epilepsy begins during childhood. The underlying mechanisms responsible for this increased excitability during this period of life are not completely understood but are clearly age-dependent. During the early postnatal period, at a time when the immature brain is highly susceptible to seizures (Jensen et al., 1992; Jensen and Baram, 2000; Khazipov et al., 2004), GABA exerts paradoxical excitatory action, indicating that in the young brain enhanced excitability is due to the excitatory rather than inhibitory actions of GABA (Dzhala and Staley, 2003; Khazipov et al., 2004). The lack of an efficient time-locked inhibition, the delayed maturation of postsynaptic GABA(B)-mediated currents and the high input resistance of small and densely packed neurons also facilitates the generation of action potentials and synchronized activities (Gaiarsa et al., 1995; McLean et al.,1996). As the brainmatures, enhanced excitatory neurotransmission may play an additional role in the propensity for the immature brain to seize as there is an overabundance of excitatory receptors (AMPA and NMDA) (Insel et al., 1990; McDonald et al., 1990; Miller et al., 1990; Brennan et al., 1997). With further maturation, axonal collaterals and attendant synapses regress (Swann et al., 1990, 1991). While seizures are common in children there is controversy regarding whether seizures result in neurological sequelae. It is known that neonatal seizures are often associated with long-term neurological consequences including post-neonatal epilepsy, behavioral problems, and mental retardation (Scher et al., 1989, 1993; Brunquell et al., 2002). While it iswidely recognized that the etiologyof the seizures is a primary determinant of outcome, there remains controversy regarding whether the occurrence of seizures themselves in the young children contribute