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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 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)
Dorsal hippocampal theta rhythm (theta) 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 theta increased linearly with the movement speed. In this preparation we found the same three types of(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)
Hyperammonemia is considered the main factor responsible for the neurological and cognitive alterations found in hepatic encephalopathy and in patients with congenital deficiencies of the urea cycle enzymes. The underlying mechanisms remain unclear. Chronic moderate hyperammonemia reduces nitric oxide-induced activation of soluble guanylate cyclase and(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)
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)
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)
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)
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)