Search results for "Cortex"
showing 10 items of 1827 documents
Mepolizumab effectiveness on small airway obstruction, corticosteroid sparing and maintenance therapy step-down in real life
2020
Background: Mepolizumab (MEP) has been recently introduced to treat severe eosinophilic asthma. Trials have demonstrated a significant effectiveness in this asthma phenotype. We evaluated MEP efficacy on lung function, symptoms, asthma exacerbations, biologic markers, steroid dependence and controller treatment level in real-life. Methods: We retrospectively analyzed 134 severe asthmatics (61 males; mean age 58.3 ± 11; mean FEV1%:72 ± 21), treated with MEP for at least 6 months (mean duration:10.9 ± 3.7 months). Results: FEV1% improved significantly after MEP. Mean FEF25-75 also increased from 37.4 ± 25.4% to 47.2 ± 27.2% (p < 0.0001). Mean baseline blood eosinophil level was 712 ± 731/μ…
Chronic fluoxetine treatment alters the structure, connectivity and plasticity of cortical interneurons
2014
Novel hypotheses suggest that antidepressants, such as the selective serotonin reuptake inhibitor fluoxetine, induce neuronal structural plasticity, resembling that of the juvenile brain, although the underlying mechanisms of this reopening of the critical periods still remain unclear. However, recent studies suggest that inhibitory networks play an important role in this structural plasticity induced by fluoxetine. For this reason we have analysed the effects of a chronic fluoxetine treatment in the hippocampus and medial prefrontal cortex (mPFC) of transgenic mice displaying eGFP labelled interneurons. We have found an increase in the expression of molecules related to critical period pla…
Cognitive control in auditory working memory is enhanced in musicians
2010
Musical competence may confer cognitive advantages that extend beyond processing of familiar musical sounds. Behavioural evidence indicates a general enhancement of both working memory and attention in musicians. It is possible that musicians, due to their training, are better able to maintain focus on task-relevant stimuli, a skill which is crucial to working memory. We measured the blood oxygenation-level dependent (BOLD) activation signal in musicians and non-musicians during working memory of musical sounds to determine the relation among performance, musical competence and generally enhanced cognition. All participants easily distinguished the stimuli. We tested the hypothesis that mus…
Functional Synaptic Projections onto Subplate Neurons in Neonatal Rat Somatosensory Cortex
2002
Subplate neurons (SPn) play an important role in the formation of thalamocortical connections during early development and show glutamatergic and GABAergic spontaneous synaptic activity. We characterized these synaptic inputs by performing whole-cell recordings from SPn in somatosensory cortical slices of postnatal day 0-3 rats. At -70 mV, electrical stimulation of the thalamocortical afferents elicited in 68% of the SPn a monosynaptic CNQX-sensitive postsynaptic current (PSC). These fast PSCs were mediated by AMPA receptors, because they were prolonged by cyclothiazide and blocked by GYKI 52466. On membrane depolarization, thalamocortical stimulation elicited in 50% of the cells an additio…
Convergence of Cortical and Sensory Driver Inputs on Single Thalamocortical Cells
2013
Ascending and descending information is relayed through the thalamus via strong, "driver" pathways. According to our current knowledge, different driver pathways are organized in parallel streams and do not interact at the thalamic level. Using an electron microscopic approach combined with optogenetics and in vivo physiology, we examined whether driver inputs arising from different sources can interact at single thalamocortical cells in the rodent somatosensory thalamus (nucleus posterior, POm). Both the anatomical and the physiological data demonstrated that ascending driver inputs from the brainstem and descending driver inputs from cortical layer 5 pyramidal neurons converge and interac…
Elevation in type I interferons inhibits HCN1 and slows cortical neuronal oscillations
2014
Central nervous system (CNS) inflammation involves the generation of inducible cytokines such as interferons (IFNs) and alterations in brain activity, yet the interplay of both is not well understood. Here, we show that in vivo elevation of IFNs by viral brain infection reduced hyperpolarization-activated currents (Ih) in cortical pyramidal neurons. In rodent brain slices directly exposed to type I IFNs, the hyperpolarization-activated cyclic nucleotide (HCN)-gated channel subunit HCN1 was specifically affected. The effect required an intact type I receptor (IFNAR) signaling cascade. Consistent with Ih inhibition, IFNs hyperpolarized the resting membrane potential, shifted the resonance fre…
Optical release of caged glutamate for stimulation of neurons in the in vitro slice preparation
2005
Optical stimulation techniques prove useful to map func- tional inputs in the in vitro brain slice preparation: Glutamate released by a focused beam of UV light induces action potentials, which can be detected in postsynaptic neurons. The direct activation effect is influenced by factors such as compound concentration, focus depth, light absorption in the tissue, and sensitivity of different neuronal do- mains. We analyze information derived from direct stimulation ex- periments in slices from rat barrel cortex and construct a computa- tional model of a layer V pyramidal neuron that reproduces the experimental findings. The model predictions concerning the influ- ence of focus depth on inpu…
Effects of manganese injected into rat nostrils: implications for in vivo functional study of olfaction using MEMRI.
2011
WOS: 000298212500007; International audience; Manganese-enhanced magnetic resonance imaging (MEMRI) is a powerful tool for visualizing neuronal pathways and mapping brain activity modulation. A potential drawback of MEMRI lies in the toxic effects of manganese (Mn), which also depend on its administration route. The aim of this study was to analyze the effects of Mn doses injected into the nostrils of rats on both olfactory perception and MRI contrast enhancement. For this purpose, doses in the range 0-8 μmol MnCl(2) were tested. Behavioral items were quantified with and without odor stimulation during the first 2 h following Mn injection. The MRI study was performed after 16 h of intermitt…
Increased cortical curvature reflects white matter atrophy in individual patients with early multiple sclerosis
2014
Objective White matter atrophy occurs independently of lesions in multiple sclerosis. In contrast to lesion detection, the quantitative assessment of white matter atrophy in individual patients has been regarded as a major challenge. We therefore tested the hypothesis that white matter atrophy (WMA) is present at the very beginning of multiple sclerosis (MS) and in virtually each individual patient. To find a new sensitive and robust marker for WMA we investigated the relationship between cortical surface area, white matter volume (WMV), and whole-brain-surface-averaged rectified cortical extrinsic curvature. Based on geometrical considerations we hypothesized that cortical curvature increa…
Allocortical neurofibrillary changes in progressive supranuclear palsy.
1992
Silver techniques for intraneuronal cytoskeleton abnormalities (neurofibrillary tangles and neuropil threads) and extracellular A4-amyloid deposits were used to examine lesions of the cerebral cortex in six cases of progressive supranuclear palsy (three were mentally unimpaired and three showed moderate degrees of dementia). Deposits of A4-amyloid protein occurred in small numbers or were absent. Neurofibrillary tangles and neuropil threads were present in all cases and were largely confined to the allocortex. A characteristic pattern of changes was found in the entorhinal cortex. The three mentally unimpaired individuals had mild cortical changes virtually confined to the transentorhinal r…