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Developing networks follow common rules to shift from silent cells to coactive networks that operate via thousands of synapses. This review deals with some of these rules and in particular those concerning the crucial role of the neurotransmitter gamma-aminobuytric acid (GABA), which operates primarily via chloride-permeable GABA(A) receptor channels. In(More)
Sensorimotor coordination emerges early in development. The maturation period is characterized by the establishment of somatotopic cortical maps, the emergence of long-range cortical connections, heightened experience-dependent plasticity and spontaneous uncoordinated skeletal movement. How these various processes cooperate to allow the somatosensory system(More)
A depolarized resting membrane potential has long been considered to be a universal feature of immature neurons. Despite the physiological importance, the underlying mechanisms of this developmental phenomenon are poorly understood. Using perforated-patch, whole cell, and cell-attached recordings, we measured the membrane potential in CA3 pyramidal cells in(More)
The behavior of immature cortical networks in vivo remains largely unknown. Using multisite extracellular and patch-clamp recordings, we observed recurrent bursts of synchronized neuronal activity lasting 0.5 to 3 seconds that occurred spontaneously in the hippocampus of freely moving and anesthetized rat pups. The influence of slow rhythms (0.33 and 0.1(More)
GABA depolarizes immature cortical neurons. However, whether GABA excites immature neocortical neurons and drives network oscillations as in other brain structures remains controversial. Excitatory actions of GABA depend on three fundamental parameters: the resting membrane potential (Em), reversal potential of GABA (E(GABA)), and threshold of action(More)
The immature brain is prone to seizures but the underlying mechanisms are poorly understood. We explored the hypothesis that increased seizure susceptibility during early development is due to the excitatory action of GABA. Using noninvasive extracellular field potential and cell-attached recordings in CA3 of Sprague-Dawley rat hippocampal slices, we(More)
During visual system development, the light-insensitive retina spontaneously generates waves of activity, which are transmitted to the lateral geniculate nucleus. The crucial question is whether retinal waves are further transmitted to the cortex and influence the early cortical patterns of activity. Using simultaneous recordings from the rat retina and(More)
The intact hippocampal formation (IHF) of neonatal or young rats can be kept alive for an extended period in a fully submerged chamber with excellent morphological preservation. Field or patch-clamp recordings, intracellular Ca2+ measurements, and 3-D reconstruction of biocytin-filled neurons can be performed routinely. The generation and propagation of(More)
We asked whether GABA(A) and NMDA receptors may act in synergy in neonatal hippocampal slices, at a time when GABA exerts a depolarizing action. The GABA(A) receptor agonist isoguvacine reduced the voltage-dependent Mg2+ block of single NMDA channels recorded in cell-attached configuration from P(2-5) CA3 pyramidal neurons and potentiated the Ca2+ influx(More)
Delta-brush is the dominant pattern of rapid oscillatory activity (8-25 Hz) in the human cortex during the third trimester of gestation. Here, we studied the relationship between delta-brushes in the somatosensory cortex and spontaneous movements of premature human neonates of 29-31 weeks postconceptional age using a combination of scalp(More)