title: Oscillatory activity in developing prefrontal networks results from theta-gamma-modulated synaptic inputs.
abstract: The hippocampus-driven entrainment of neonatal prefrontal circuits in theta-gamma oscillations contributes to the maturation of cognitive abilities, yet the underlying synaptic mechanisms are still unknown. Here we combine patch-clamp recordings from morphologically and neurochemically characterized layer V pyramidal neurons and interneurons in vivo, with extracellular recordings from the prelimbic cortex (PL) of awake and lightly anesthetized neonatal rats, to elucidate the synaptic framework of early network oscillations. We demonstrate that all neurons spontaneously fire bursts of action potentials. They receive barrages of fast and slow glutamatergic as well as GABAergic synaptic inputs. Oscillatory theta activity results from long-range coupling of pyramidal neurons, presumably within prelimbic-hippocampal circuits, and from local interactions between interneurons. In contrast, beta-low gamma activity requires external glutamatergic drive on prelimbic interneurons. High-frequency oscillations in layer V are independent of interactions at chemical synapses. Thus, specific theta-gamma-modulated synaptic interactions represent the substrate of network oscillations in the developing PL.
authors: Developmental Neurophysiology, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany.
authors: Sebastian H
authors: SH
authors: Bitzenhofer
authors: Developmental Neurophysiology, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany.
authors: Kay
authors: K
authors: Sieben
authors: Developmental Neurophysiology, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany.
authors: Kai D
authors: KD
authors: Siebert
authors: Department of Chemosensation, Institute for Biology II, RWTH Aachen University, 52074 Aachen, Germany.
authors: Marc
authors: M
authors: Spehr
authors: Developmental Neurophysiology, Institute of Neuroanatomy, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany. Electronic address: hangop@zmnh.uni-hamburg.de.
authors: Ileana L
authors: IL
authors: Hanganu-Opatz
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D065818:Gamma Rhythm / Q000502:physiology; D007150:Immunohistochemistry; D007395:Interneurons / Q000502:physiology*; D018613:Microscopy, Confocal; D055495:Neurogenesis / Q000502:physiology*; D018408:Patch-Clamp Techniques; D017397:Prefrontal Cortex / Q000254:growth & development / Q000502:physiology*; D017966:Pyramidal Cells / Q000502:physiology*; D051381:Rats; D009435:Synaptic Transmission / Q000502:physiology*; D013826:Theta Rhythm / Q000502:physiology