Search results for "Gyrus"
showing 10 items of 277 documents
Modulatory effects of nitric oxide-active drugs on the anticonvulsant activity of lamotrigine in an experimental model of partial complex epilepsy in…
2007
Abstract Background The effects induced by administering the anticonvulsant lamotrigine, the preferential inhibitor of neuronal nitric oxide synthase 7-nitroindazole and the precursor of NO synthesis L-arginine, alone or in combination, on an experimental model of partial complex seizures (maximal dentate gyrus activation) were studied in urethane anaesthetized rats. The epileptic activity of the dentate gyrus was obtained through the repetitive stimulation of the angular bundle and maximal dentate gyrus activation latency, duration and post-stimulus afterdischarge duration were evaluated. Results Either Lamotrigine (10 mg kg-1) or 7-nitroindazole (75 mg kg-1) i.p. administration had an ant…
Neocortical Variation of Abeta Load in Fully Expressed, Pure Alzheimer's Disease
2010
The relationship between amyloid-beta (A beta) deposition and tau-related neurofibrillary changes is a key issue in the pathogenesis of Alzheimer's disease (AD). The aim of this study was to investigate the extent and cortical distribution of A beta and tau pathology, their mutual links and their correlation with the duration of the disease in thirty-nine patients with fully expressed AD. By tau immunohistochemistry, we identified different patterns of distribution of neurofibrillary changes that were ascribed to Braak stage V and VI. The disease duration was longer in patients at Braak stage VI than in those at V. Morphometric analysis carried out in several neocortical areas demonstrated …
N-methyl-d-aspartate receptor expression during adult neurogenesis in the rat dentate gyrus.
2006
Abstract N -methyl- d -aspartate (NMDA) receptors play a crucial role in the regulation of neuronal development during embryogenesis and they also regulate the rate of neurogenesis and proliferation in the adult dentate gyrus. However, the mechanism by which they influence these processes is not fully understood. NMDA receptors seem to be functional in hippocampal precursor cells and recently generated granule neurons, although there is no anatomical correlate of these physiological observations. We have analyzed the expression of the NMDA receptor subunits NR1 and NR2B in precursor cells and recently generated granule neurons of the adult rat dentate gyrus, using 5′bromodeoxyuridine, green…
Role(s) of the 5-HT2C receptor in the development of maximal dentate activation in the hippocampus of anesthetized rats.
2014
Aims: Substantial evidence indicates that 5-HT2C receptors are involved in the control of neuronal network excitability and in seizure pathophysiology. Here, we have addressed the relatively unexplored relationship between temporal lobe epilepsy (TLE), the most frequent type of intractable epilepsy, and 5-HT2CRs. Methods: In this study, we investigated this issue using a model of partial complex (limbic) seizures in urethane-anesthetized rat, based on the phenomenon of maximal dentate activation (MDA) using 5-HT2C compounds, electrophysiology, immunohistochemistry, and western blotting techniques. Results: The 5-HT2C agonists mCPP (1 mg/kg, i.p) and lorcaserin (3 mg/kg, i.p), but not RO60-0…
Feeling addressed! The neural processing of social communicative cues in patients with major depression
2020
Abstract The feeling of being addressed is the first step in a complex processing stream enabling successful social communication. Social impairments are a relevant characteristic of patients with major depressive disorder (MDD). Here, we investigated a mechanism which—if impaired—might contribute to withdrawal or isolation in MDD, namely, the neural processing of social cues such as body orientation and gesture. During funtional magnetic resonance imaging (fMRI) data acquisition, 33 patients with MDD and 43 healthy control subjects watched video clips of a speaking actor: one version with a gesture accompanying the speech and one without gesture. Videos were filmed simultaneously from two …
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…
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…
Metabolic changes in vestibular and visual cortices in acute vestibular neuritis
2004
Five right-handed patients with a right-sided vestibular neuritis were examined twice with fluorodeoxyglucose positron emission tomography while lying supine with eyes closed: once during the acute stage (mean, 6.6 days) and then 3 months later when central vestibular compensation had occurred. Regional cerebral glucose metabolism (rCGM) was significantly increased (p <0.001 uncorrected) during the acute stage in multisensory vestibular cortical and subcortical areas (parietoinsular vestibular cortex in the posterior insula, posterolateral thalamus, anterior cingulate gyrus [Brodmann area 32/24], pontomesencephalic brainstem, hippocampus). Simultaneously, there was a significant rCGM decrea…
A critical period for experience-dependent remodeling of adult-born neuron connectivity.
2015
Neurogenesis in the dentate gyrus (DG) of the adult hippocampus is a process regulated by experience. To understand whether experience also modifies the connectivity of new neurons, we systematically investigated changes in their innervation following environmental enrichment (EE). We found that EE exposure between 2-6 weeks following neuron birth, rather than merely increasing the number of new neurons, profoundly affected their pattern of monosynaptic inputs. Both local innervation by interneurons and to even greater degree long-distance innervation by cortical neurons were markedly enhanced. Furthermore, following EE, new neurons received inputs from CA3 and CA1 inhibitory neurons that w…
Dentate spikes and learning : disrupting hippocampal function during memory consolidation can improve pattern separation
2018
Hippocampal dentate spikes (DSs) are short-duration, large-amplitude fluctuations in hilar local field potentials and take place while resting and sleeping. During DSs, dentate gyrus granule cells increase firing while CA1 pyramidal cells decrease firing. Recent findings suggest DSs play a significant role in memory consolidation after training on a hippocampus-dependent, nonspatial associative learning task. Here, we aimed to find out whether DSs are important in other types of hippocampus-dependent learning tasks as well. To this end, we trained adult male Sprague-Dawley rats in a spatial reference memory task, a fixed interval task, and a pattern separation task. During a rest period im…