Search results for " cerebral cortex"
showing 10 items of 15 documents
Anxiolytic effects of muscarinic acetylcholine receptors agonist oxotremorine in chronically stressed rats and related changes in BDNF and FGF2 level…
2017
Rationale: In depressive disorders, one of the mechanisms proposed for antidepressant drugs is the enhancement of synaptic plasticity in the hippocampus and cerebral cortex. Previously, we showed that the muscarinic acetylcholine receptor (mAChR) agonist oxotremorine (Oxo) increases neuronal plasticity in hippocampal neurons via FGFR1 transactivation. Objectives: Here, we aimed to explore (a) whether Oxo exerts anxiolytic effect in the rat model of anxiety-depression-like behavior induced by chronic restraint stress (CRS), and (b) if the anxiolytic effect of Oxo is associated with the modulation of neurotrophic factors, brain-derived neurotrophic factor (BDNF) and fibroblast growth factor-2…
The cholinergic system in Down's syndrome
2006
The cholinergic system is one of the most important modulatory neurotransmitter systems in the brain. Alterations of the transmission communicators are accompanied by reduction of the cortical activity, which is associated with a learning and memory deficit. Down's syndrome is a pathological condition characterized by a high number of abnormalities that involve the brain.The cholinergic system is involved in alterations of the neurological system such as severe learning difficulties.To explain these alterations, important results are obtained from studies about murine trisomy 16 (animal model of Down's syndrome).The results obtained provide useful elements in the improvement of knowledge ab…
Brain activity during intra- and cross-modal priming: new empirical data and review of the literature
2003
A positron emission tomography (PET) study was conducted to investigate the neurofunctional correlate of auditory within-modality and auditory-to-visual cross-modality stem completion priming. Compared to the auditory-to-auditory priming condition, cross-modality priming was associated with a significantly larger regional cerebral blood flow (rCBF) decrease at the boundary between left inferior temporal and fusiform gyri, brain regions previously associated with modality independent lexical retrieval and reading. Instead, within-modality auditory priming was associated with a bilateral pattern of prefrontal rCBF increase. This was likely the expression of more efficient access to output lex…
Plasticity of brain wave network interactions and evolution across physiologic states
2015
Neural plasticity transcends a range of spatio-temporal scales and serves as the basis of various brain activities and physiologic functions. At the microscopic level, it enables the emergence of brain waves with complex temporal dynamics. At the macroscopic level, presence and dominance of specific brain waves is associated with important brain functions. The role of neural plasticity at different levels in generating distinct brain rhythms and how brain rhythms communicate with each other across brain areas to generate physiologic states and functions remains not understood. Here we perform an empirical exploration of neural plasticity at the level of brain wave network interactions repre…
Auditory temporal processing deficits in patients with insular stroke
2006
OBJECTIVE: To assess central auditory function in a series of patients with stroke of the insula and adjacent areas. METHODS: The authors recruited eight patients with stroke affecting the insula and adjacent areas and eight neurologically normal controls (matched to the patients for age, sex, handedness, and hearing thresholds). The lesion spared the adjacent auditory areas in three patients and included other auditory structures in five cases. The authors conducted pure-tone audiometry and tympanometry and a central auditory test battery, which included the dichotic digits, and three temporal tests, the duration pattern, frequency pattern, and gaps in noise tests. They collected informati…
Quantitative mass spectrometry for human melanocortin peptides in vitro and in vivo suggests prominent roles for β-MSH and desacetyl α-MSH in energy …
2018
Objective The lack of pro-opiomelanocortin (POMC)-derived melanocortin peptides results in hypoadrenalism and severe obesity in both humans and rodents that is treatable with synthetic melanocortins. However, there are significant differences in POMC processing between humans and rodents, and little is known about the relative physiological importance of POMC products in the human brain. The aim of this study was to determine which POMC-derived peptides are present in the human brain, to establish their relative concentrations, and to test if their production is dynamically regulated. Methods We analysed both fresh post-mortem human hypothalamic tissue and hypothalamic neurons derived from …
Resonance of cortico-cortical connections of the motor system with the observation of goal directed grasping movements
2010
Goal directed movements require the activation of parietal, premotor and primary motor areas. In monkeys, neurons of these areas become active also during the observation of movements performed by others, especially for coding the goal of the action (mirror system). Using bifocal transcranial magnetic stimulation (TMS) in healthy subjects, we tested whether the observation of goal directed reach to grasp actions may lead to specific changes in the short-latency connections linking key areas of the mirror system, such as the anterior intraparietal cortex (AIP) and the ventral premotor cortex (PMv), with the primary motor cortex (M1). We found that AIP-M1 and PMv-M1 cortico-cortical interacti…
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…
Biased postural vertical in humans with hemispheric cerebral lesions.
1998
International audience; This study was aimed at demonstrating the existence of a biased postural vertical in humans with a recent cerebral lesion. The postural vertical of patients and controls was analysed comparatively using a self-regulated balancing task, performed in sitting posture. Patients displayed a quite constant (19/22) contralesional tilt of the postural vertical (mean -2.6 degrees), varying with the severity of their spatial neglect and hemianaethesia. Eight of them showed a pathological contralesional bias (mean -5.5 degrees) as compared to normals. This result indicates an asymmetric process of somatic graviceptive information due to some cerebral lesions. When patients were…
Evidence for reading improvement following tDCS treatment in children and adolescents with Dyslexia.
2016
Purpose There is evidence that non-invasive brain stimulation transitorily modulates reading by facilitating the neural pathways underactive in individuals with dyslexia. The study aimed at investigating whether multiple sessions of transcranial direct current stimulation (tDCS) would enhance reading abilities of children and adolescents with dyslexia and whether the effect is long-lasting. Methods Eighteen children and adolescents with dyslexia received three 20-minute sessions a week for 6 weeks (18 sessions) of left anodal/right cathodal tDCS set at 1 mA over parieto-temporal regions combined with a cognitive training. The participants were randomly assigned to the active or the sham tre…