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The aim of this work was to assess whether ammonia concentrations similar to the increase found in the brain of hyperammonemic rats (100 microM), impair N-methyl-D-aspartate (NMDA) receptor-mediated signal transduction. We first measured glutamate neurotoxicity, which in these neurons is mediated by activation of NMDA receptors, as an initial parameter(More)
In rodents, cortical interneurons originate from the medial ganglionic eminence (MGE) and caudal ganglionic eminence (CGE) according to precise temporal schedules. The mechanisms controlling the specification of CGE-derived interneurons and their role in cortical circuitry are still unknown. Here, we show that COUP-TFI expression becomes restricted to the(More)
The firing pattern of 96 neuron in the medial septal nucleus (MSN) and diagonal band of Broca (DBB) and their functional relationships with hippocampal theta generators were investigated in rats during physostigmine-induced hippocampal theta rhythm (theta). Three types of discharge were found. (a) Type 1 (74%), in rhythmic bursts phase-locked with theta.(More)
Dorsal hippocampal theta rhythm (Θ) and extracellular unit activity from CA1 pyramidal layer were recorded in awake guinea pigs, both during standing and during walking on a conveyor belt at increasing speeds. Amplitude, frequency and rhythmicity of Θ increased linearly with the movement speed. In this preparation we found the same three types of unit(More)
The activity from 55 septohippocampal neuron pairs was examined in rats anesthetized with urethane. In addition to the statistical characterization of the firing patterns of the recorded units, the functional interactions between pairs of neurons and between neurons and hippocampal theta (theta) waves were investigated with cross-correlation techniques.(More)
To compare the ongoing electrical activity in possibly homologous structures of reptiles and mammals, the electrographic activity (micro-EEG) from major parts of the cortex of unanesthetized turtles (Pseudemys) and geckos (Gekko) was recorded with and without acute and chronic stimuli, physostigmine and atropine. Electrodes were placed in the medial cortex(More)
Rat hippocampal EEG and motor activity were studied during 15 days in relation to the vigilance state and to the light-dark cycle with a computerized system. During slow-wave sleep (SS) the hippocampal EEG has an outstanding mean power density in the theta band, similar to the large values present during paradoxical sleep. A circadian modulation was found(More)
Electroencephalographic recordings in cirrhotic patients without overt hepatic encephalopathy (HE) have mainly been performed during wakefulness. Our aim was to quantify their alterations in nocturnal sleep electroencephalogram (EEG). In 20 patients and 20 healthy volunteers, we recorded a nocturnal digital polysomnography. Different sleep parameters were(More)
Hippocampal and entorhinal cortex glucose metabolism were studied by 14C-2-deoxyglucose (2-DG) autoradiography in anesthetized rats with and without continuous theta rhythm (theta). 2-Deoxyglucose changes in specific cytoarchitectonic regions were precisely assessed by n innovative approach. In the absence of theta there were areas with a higher glucose(More)
Long-term potentiation of excitatory synaptic transmission was studied in an in vitro turtle brain that manifests spontaneous electrocorticogram activity. We show that in the turtle medial cortex, there is evidence of homosynaptic long-term potentiation in the septum-medial cortex pathway. This potentiation has two components, one dependent on NMDA receptor(More)