Search results for "Cerebral Cortex"
showing 10 items of 529 documents
Changes in the expression of cation-Cl- cotransporters, NKCC1 and KCC2, during cortical malformation induced by neonatal freeze-lesion.
2007
Focal cortical malformations comprise a heterogeneous group of disturbances in brain development, often associated with intractable epilepsy. A focal freeze-lesion of cerebral cortex in newborn rat produces a cortical malformation that resembles human polymicrogyria, clinical conditions that results from abnormal neuronal migration. The change in GABAergic functions that occurs during early brain development is induced by an alteration in Cl(-) homeostasis and plays important roles in neocortical development by modulating such events as laminar organization and synaptogenesis. We therefore investigated the relationship between pathogenesis of polymicrogyria and ontogeny of Cl(-) homeostasis…
Electrophysiological correlates of the cognitive control processes underpinning mixing and switching costs
2016
Typically, in task-switching contexts individuals are slower and less accurate when repeating a task in mixed blocks compared to single-task blocks (mixing cost) and when switching to a new task compared to repeating a previous one (switch cost). Previous research has shown that distinct electrophysiological correlates underlie these two phenomena. However, this evidence is not a consistent result. The goal of this study was to better characterize differences between the control processes involved in mixing and switch costs. To this aim, we examined event-related potentials (ERPs) evoked during a cued task-switching experiment. In order to minimize the confounding effects of cognitive deman…
The expression of the Goodpasture antigen-binding protein (ceramide transporter) in adult rat brain
2009
The Goodpasture antigen-binding protein (GPBP) plays a critical role in brain development. Knockdown of GPBP leads to loss of myelinated tracts in the central nervous system and to extensive apoptosis in the brain during early embryogenesis. GPBP was initially identified as a protein associated with the autoantigen in Goodpasture autoimmune syndrome, where it was shown to be a kinase that regulates type IV collagen organization. GPBP isoforms bind and transport ceramide from the endoplasmic reticulum to the Golgi apparatus and are therefore also known as ceramide transporters (CERT). Ceramide dysregulation is involved in autoimmunity and neurodegenerative disorders. In order to analyze the …
Cellular expression of α4 subunit mRNA of the nicotinic acetylcholine receptor in the developing rat telencephalon
1995
By contrast to adult brain, little is known on the development of nicotinic acetylcholine receptor (nAChR) expression. Using a digoxigenin-labeled riboprobe for in situ hybridization, alpha 4 nAChR subunit mRNA expression was studied in embryonic and postnatal rat neocortex and hippocampus where it was transiently increased in neuronal subpopulations and preceded cholinergic fiber ingrowth. alpha 4 expression was increased in neocortical layer VIb between E20 and P2 and, about birth, in dentate gyrus granule cells subsequently decreasing to adult levels. nAChR mRNA expression is increased at the developing neuromuscular endplate preceding cholinergic innervation which triggers changes in no…
Electrophysiology and neuronal integrity following systemic arterial hypotension in a rat model of unilateral carotid artery occlusion.
2007
Patients with carotid artery stenosis may be particularly susceptible to hypotension-associated cerebral ischemia and subsequent neurological sequelae. Measuring somatosensory evoked potentials (SEP), electroencephalogram (EEG), direct current (DC) potential, and histology, we compared the temporal evolution of cortical functional perturbations as well as neuronal integrity in a model of unilateral carotid artery occlusion and systemic hypobaric hypotension (HH) at the lower limit of cerebral blood flow autoregulation (50 mm Hg). Serial measurements of EEG power spectra as well as SEP-amplitudes and latencies of N10.3 were performed before, during, and up to 60 min after 30 min-HH (n=7) or …
Photochemically induced, graded cerebral infarction in the mouse by laser irradiation evolution of brain edema
1992
Cerebral infarction was produced in mice by intravenous injection of a photosensitive dye, rose bengal (10 mg/kg), and by focal illumination of the intact skull surface for 3 min with a laser source, operating at 570 nm with power levels of 2, 5, 10, and 20 mW. Location of infarction was made using 2,3,5-triphenyltetrazolium chloride and the time course of edema in the irradiated cerebral hemisphere was evaluated by measuring water, sodium, and potassium content 4, 24, and 72 hr after irradiation. With power levels of 2 and 5 mW, the infarct was restricted to the cortex, whereas with power levels of 10 and 20 mW, it extended to subcortical regions. Increases in water and sodium and decrease…
Neuron regeneration reverses 3-acetylpyridine-induced cell loss in the cerebral cortex of adult lizards
1991
Systemic administration of the neurotoxin 3-acetylpyridine to adult lizards results in extensive loss of neurons in the medial cerebral cortex, other brain areas remaining largely unaffected. After the neurotoxic trauma, new cells are produced by mitotic division of cells in the ventricular wall. The new cells migrate along radial glial fibers and replace lost neurons in the medial cortex. Electron microscopic examination of cells labeled with [3H]thymidine confirms that the newly generated cells are neurons. Thus, neuron regeneration can occur in the cerebral cortex of adult lizards.
Reading for meaning in dyslexic and young children : distinct neural pathways but common endpoints
2009
Developmental dyslexia is a highly prevalent and specific disorder of reading acquisition characterised by impaired reading fluency and comprehension. We have previously identified fMRI- and ERP-based neural markers of impaired sentence reading in dyslexia that indicated both deviant basic word processing and deviant semantic incongruency processing. However, it remained unclear how specific these impairments are for dyslexia, as they occurred when children with dyslexia (DYS) were compared to chronological age-matched controls (CA) who also differ in the amount of reading experience. Adding a younger control group at a similar reading level (RL) as the dyslexic group, we examined here whic…
Acute inactivation of the medial forebrain bundle imposes oscillations in the SNr: a challenge for the 6-OHDA model?
2010
It has been recently shown that the substantia nigra pars reticulata (SNr) of 6-hydroxydopamine (6-OHDA)-lesioned rats, under urethane anaesthesia, manifests a prominent low frequency oscillation (LFO) of around 1Hz, synchronized with cortical slow wave activity (SWA). Nevertheless, it is poorly understood whether these electrophysiological alterations are correlated only with severe dopamine depletion or may also play a relevant pathogenetic role in the early stages of the dopamine denervation. Hence, here we recorded SNr single units and electrocorticogram (ECoG) in two models of dopamine denervation: (i) acute dopamine denervated rats, obtained by injection of tetrodotoxin (TTX), (ii) ch…
Children with dyslexia lack multiple specializations along the visual word-form (VWF) system.
2009
Developmental dyslexia has been associated with a dysfunction of a brain region in the left inferior occipitotemporal cortex, called the "visual word-form area" (VWFA). In adult normal readers, the VWFA is specialized for print processing and sensitive to the orthographic familiarity of letter strings. However, it is still unclear whether these two levels of occipitotemporal specialization are affected in developmental dyslexia. Specifically, we investigated whether (a) these two levels of specialization are impaired in dyslexic children with only a few years of reading experience and (b) whether this impairment is confined to the left inferior occipitotemporal VWFA, or extends to adjacent …