GABAergic control of CA3-driven network events in the developing hippocampus

Abstract

Endogenous activity is a characteristic feature of developing neuronal networks. In the neonatal rat hippocampus, spontaneously occurring network events known as "Giant Depolarizing Potentials" (GDPs) are seen in vitro at a stage when GABAergic transmission is depolarizing. GDPs are triggered by the CA3 region and they are seen as brief recurrent events in field-potential recordings, paralleled by depolarization and spiking of pyramidal neurons. In the light of current data, GDPs are triggered by the glutamatergic pyramidal neurons which act as conditional pacemakers, while the depolarizing action of GABA plays a permissive role for the generation of these events in in vitro preparations. From an in vivo perspective, GDPs appear to be an immature form of hippocampal sharp waves. © 2007 Springer-Verlag Berlin Heidelberg.