Search results for "Brain Mapping"
showing 10 items of 396 documents
Mathematical models for the diffusion magnetic resonance signal abnormality in patients with prion diseases
2014
In clinical practice signal hyperintensity in the cortex and/or in the striatum on magnetic resonance (MR) diffusion-weighted images (DWIs) is a marker of sporadic Creutzfeldt–Jakob Disease (sCJD). MR diagnostic accuracy is greater than 90%, but the biophysical mechanisms underpinning the signal abnormality are unknown. The aim of this prospective study is to combine an advanced DWI protocol with new mathematical models of the microstructural changes occurring in prion disease patients to investigate the cause of MR signal alterations. This underpins the later development of more sensitive and specific image-based biomarkers. DWI data with a wide a range of echo times and diffusion weightin…
Effect of cholinergic stimulation in early Alzheimer's disease - functional imaging during a recognition memory task.
2011
Treatment of Alzheimer's disease (AD) with acetylcholinesterase inhibitors (AChEI) enhances cholinergic activity and alleviates clinical symptoms. In the present functional magnetic resonance imaging (fMRI) study, we investigated the effect of the AChEI rivastigmine on cognitive function and brain activation patterns during a face recognition memory task. Twenty patients with newly-diagnosed mild AD were administered a single oral dose of placebo, a single dose of rivastigmine (acute), and twice-daily treatment with rivastigmine for 4 weeks (chronic). After each treatment, the patients underwent a facial recognition task during fMRI. The prefrontal areas known to be involved in face recogni…
Using Diffusion Tensor Imaging to Evaluate Microstructural Changes and Outcomes after Radiofrequency Rhizotomy of Trigeminal Nerves in Patients with …
2016
Trigeminal neuralgia is characterized by facial pain that may be sudden, intense, and recurrent. Our aim was to investigate microstructural tissue changes of the trigeminal nerve in patients with trigeminal neuralgia resulting from neurovascular compression by diffusion tensor imaging, and to test the predictive value of diffusion tensor imaging for determining outcomes after radiofrequency rhizotomy. Forty-three patients with trigeminal neuralgia were recruited, and diffusion tensor imaging was performed before radiofrequency rhizotomy. By selecting the cisternal segment of the trigeminal nerve manually, we measured the volume of trigeminal nerve, fractional anisotropy, apparent diffusion …
The reliability of continuous brain responses during naturalistic listening to music
2015
Low-level (timbral) and high-level (tonal and rhythmical) musical features during continuous listening to music, studied by functional magnetic resonance imaging (fMRI), have been shown to elicit large-scale responses in cognitive, motor, and limbic brain networks. Using a similar methodological approach and a similar group of participants, we aimed to study the replicability of previous findings. Participants' fMRI responses during continuous listening of a tango Nuevo piece were correlated voxelwise against the time series of a set of perceptually validated musical features computationally extracted from the music. The replicability of previous results and the present study was assessed b…
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…
Immediate effects of active versus passive scapular correction on pain and pressure pain threshold in patients with chronic neck pain.
2012
OBJECTIVE: The purpose of this study was to investigate the effect of active vs passive scapular correction on pain and pressure pain threshold at the most symptomatic cervical segment in patients with chronic neck pain. METHODS: Twenty-three volunteers with chronic, idiopathic neck pain were recruited (age, 38.9 ± 14.4 years; sex [man/woman], 3/20; Neck Disability Index, 28.1% ± 9.9%). Subjects were randomly allocated to 2 groups: active scapular correction or passive scapular correction. Pressure pain threshold and pain intensity rated on a numerical rating scale during a posteroanterior glide over the most symptomatic cervical segment were measured before and immediately after the active…
In vivo imaging of dopamine receptors in a model of temporal lobe epilepsy
2010
Alterations in dopamine neurotransmission in animal models of epilepsies have been frequently demonstrated using invasive neuroscience or ex vivo techniques. We aimed to test whether corresponding alterations could be detected by noninvasive in vivo brain imaging with positron emission tomography (PET) in the chronic phase of the rat pilocarpine model of temporal lobe epilepsy.Six pilocarpine-treated Wistar rats exhibiting spontaneous recurrent seizures and nine control rats were studied with PET using [(18)F]-fallypride, a high-affinity dopamine D(2/3) receptor ligand. Parametric images of [(18)F]-fallypride specific binding were calculated using a reference tissue method, and the two grou…
Cognitive estimation: Performance of patients with focal frontal and posterior lesions
2018
The Cognitive Estimation Test (CET) is a widely used test to investigate estimation abilities requiring complex processes such as reasoning, the development and application of appropriate strategies, response plausibility checking as well as general knowledge and numeracy (e.g., Shallice and Evans, 1978; MacPherson et al., 2014). Thus far, it remains unknown whether the CET is both sensitive and specific to frontal lobe dysfunction. Neuroimaging techniques may not represent a useful methodology for answering this question since the complex processes involved are likely to be associated with a large network of brain regions, some of which are not functionally necessary to successfully carry …
Enhancement of brain event-related potentials to speech sounds is associated with compensated reading skills in dyslexic children with familial risk …
2014
Specific reading disability, dyslexia, is a prevalent and heritable disorder impairing reading acquisition characterized by a phonological deficit. However, the underlying mechanism of how the impaired phonological processing mediates resulting dyslexia or reading disabilities remains still unclear. Using ERPs we studied speech sound processing of 30 dyslexic children with familial risk for dyslexia, 51 typically reading children with familial risk for dyslexia, and 58 typically reading control children. We found enhanced brain responses to shortening of a phonemic length in pseudo-words (/at:a/ vs. /ata/) in dyslexic children with familial risk as compared to other groups. The enhanced bra…
THE EFFECTS OF AGING ON DOPAMINERGIC NEUROTRANSMISSION A microPET STUDY OF [11C]-raclopride BINDING IN THE AGED RODENT BRAIN
2010
Rodent models are frequently used in aging re search to investigate biochemical age effects and aid in the development of therapies for pathological and non pathological age related degenerative processes In order to validate the use of animal models in aging research and pave the way for longitudinal intervention based animal studies, the consistency of cerebral aging processes across species needs to be evaluated The dopaminergic system seems particularly susceptible to the aging process, and one of the most consistent findings in human brain aging research is a decline in striatal D2-like receptor (D2R) availability, quantifiable by positron emission tomography (PET) imaging In this stud…