A5018565112- Advanced MRI Techniques and Applications
- Functional Brain Connectivity Studies
- Advanced NMR Techniques and Applications
- Neuroscience and Neuropharmacology Research
- Advanced Neuroimaging Techniques and Applications
- Neural dynamics and brain function
- Medical Imaging Techniques and Applications
- Diet and metabolism studies
- Electron Spin Resonance Studies
- Tryptophan and brain disorders
- Alzheimer's disease research and treatments
- Lanthanide and Transition Metal Complexes
- Transcranial Magnetic Stimulation Studies
- Dementia and Cognitive Impairment Research
- MRI in cancer diagnosis
- NMR spectroscopy and applications
- Metabolomics and Mass Spectrometry Studies
- EEG and Brain-Computer Interfaces
- Memory and Neural Mechanisms
- Neurological disorders and treatments
- Atomic and Subatomic Physics Research
- Stress Responses and Cortisol
- Visual perception and processing mechanisms
- Mitochondrial Function and Pathology
- Neural and Behavioral Psychology Studies
Sunnybrook Health Science Centre
2021-2025
Sunnybrook Research Institute
2021-2025
University of Toronto
2021-2025
John Wiley & Sons (United States)
2024
Hudson Institute
2024
Douglas Mental Health University Institute
2015-2024
McGill University
2015-2024
Toronto General Hospital
2024
Sunnybrook Hospital
2023-2024
Concordia University
2024
Magnetic resonance spectroscopy (MRS) allows measurement of neurotransmitter concentrations within a region interest in the brain. Inter-individual variation MRS-measured GABA levels have been related to task performance number regions. However, it is not clear how MRS-assessed measures relate cortical excitability or GABAergic synaptic activity. We therefore performed two studies investigating relationship between as assessed by MRS and transcranial magnetic stimulation (TMS) activity...
To introduce a new toolkit for simulation and processing of magnetic resonance spectroscopy (MRS) data, to demonstrate some its novel features.The FID appliance (FID-A) is an open-source, MATLAB-based software MRS data. The designed specifically data with multiple dimensions (eg, radiofrequency channels, averages, spectral editing dimensions). It equipped functions importing in the formats most major MRI vendors Siemens, Philips, GE, Agilent) exporting into several common packages LCModel,...
Once an MRS dataset has been acquired, several important steps must be taken to obtain the desired metabolite concentration measures. First, data preprocessed prepare them for analysis. Next, intensity of signal(s) interest estimated. Finally, measured signal intensities converted into scaled units employing a quantitative reference allow meaningful interpretation. In this paper, we review these three main in post‐acquisition workflow single‐voxel experiment (preprocessing, analysis and...
Purpose Frequency and phase drifts are a common problem in the acquisition of vivo magnetic resonance spectroscopy (MRS) data. If not accounted for, frequency will result artifactual broadening spectral peaks, distortion lineshapes, reduction signal‐to‐noise ratio (SNR). We present herein new method for estimating correcting MRS Methods used simple fitting each average to reference scan (often first series) time domain through adjustment terms. Due similarity with image registration, this is...
We previously demonstrated that network level functional connectivity in the human brain could be related to levels of inhibition a major node at baseline (Stagg et al., 2014). In this study, we build upon finding directly investigate effects perturbing M1 GABA and resting state using transcranial direct current stimulation (tDCS), neuromodulatory approach has been modulate both metrics. FMRI data levels, as assessed by Magnetic Resonance Spectroscopy, were measured before after 20 min 1 mA...
The translation of MRS to clinical practice has been impeded by the lack technical standardization. There are multiple methods acquisition, post‐processing, and analysis whose details greatly impact interpretation results. These often not fully reported, making it difficult assess studies on a standardized basis. This hampers reviewing manuscripts, limits reproducibility study results, complicates meta‐analysis literature. In this paper consensus group experts provides minimum guidelines for...
Anatomically plausible networks of functionally inter-connected regions have been reliably demonstrated at rest, although the neurochemical basis these ‘resting state networks’ is not well understood. In this study, we combined magnetic resonance spectroscopy (MRS) and resting fMRI an inverse relationship between levels inhibitory neurotransmitter GABA within primary motor cortex (M1) strength functional connectivity across network. This was both neurochemically anatomically specific. We...
Importance National Institute on Aging–Alzheimer’s Association (NIA-AA) workgroups have proposed biological research criteria intended to identify individuals with preclinical Alzheimer disease (AD). Objective To assess the clinical value of these older without cognitive impairment who are at near-term risk developing symptomatic AD. Design, Setting, and Participants This longitudinal cohort study used data from 4 independent population-based cohorts (PREVENT-AD, HABS, AIBL, Knight ADRC)...
Background and Objective. γ-Aminobutyric acid (GABA) is the dominant inhibitory neurotransmitter in brain important motor learning. We aimed to measure GABA content primary cortex poststroke (using GABA-edited magnetic resonance spectroscopy [MRS]) relation recovery during 2 weeks of constraint-induced movement therapy (CIMT). Methods. Twenty-one patients (3-12 months poststroke) 20 healthy subjects were recruited. Magnetic imaging structural T1 MRS performed at baseline after CIMT, once...
Learning novel motor skills alters local inhibitory circuits within primary cortex (M1) (Floyer-Lea et al., 2006) and changes long-range functional connectivity (Albert 2009). Whether such effects occur with long-term training is less well established. In addition, the relationship between learning-related in inhibition, their modulation by practice, has not previously been tested. Here, we used resting-state magnetic resonance imaging (rs-fMRI) to assess MR spectroscopy quantify GABA before...
Purpose To investigate the quantitative impact of frequency drift on Gamma-Aminobutyric acid (GABA+)-edited MRS human brain at 3 Tesla (T). Methods Three sequential GABA+-edited MEGA-PRESS acquisitions were acquired in fifteen sessions; ten these, was preceded by functional MRI (fMRI) to induce drift, which estimated from creatine resonance 3.0 ppm. Simulations performed examine effects editing efficiency GABA and co-edited macromolecules (MM) subtraction artifacts GABA+ quantification. The...
Significance In vitro and modeling studies have indicated that GABAergic signaling underlies gamma oscillations. It would be valuable to measure this correlation between GABA oscillations in the human brain, a recent study [Muthukumaraswamy SD, et al. (2009) Proc Natl Acad Sci USA 106(20):8356–8361] is possible, using magnetoencephalography magnetic resonance spectroscopy. If true, such make peak frequency useful surrogate marker of cortical excitability for investigating clinical...
With a 40‐year history of use for in vivo studies, the terminology used to describe methodology and results magnetic resonance spectroscopy (MRS) has grown substantially is not consistent many aspects. Given platform offered by this special issue on advanced MRS methodology, authors decided implicated terms, pinpoint differences their meanings suggest specific uses or definitions. This work covers terms all aspects MRS, starting from description MR signal its theoretical basis acquisition...
Purpose The purpose of this study is to present a cloud‐based spectral simulation tool “MRSCloud,” which allows MRS users simulate vendor‐specific and sequence‐specific basis set online in convenient time‐efficient manner. This can sets for GE, Philips, Siemens MR scanners, including conventional acquisitions editing schemes with PRESS semi‐LASER localization at 3 T. Methods MRSCloud was built on the functionality FID‐A software package. We added three extensions accelerate computation (ie,...
Magnetic resonance spectroscopy (MRS) is an acceptable non-invasive means of studying brain neurochemistry in depression. Previous studies depressed patients have focused on measurement the amino acid neurotransmitters, γ-aminobutyric (GABA) and glutamate.The aim this study to use MRS conjunction with ultrashort echo time 'SPECIAL' technique measure cortical levels GABA, glutamate glutathione (GSH) unmedicated major We also examined effect 6-week treatment selective serotonin re-uptake...
Short‐TE MRS has been proposed recently as a method for the in vivo detection and quantification of γ‐aminobutyric acid (GABA) human brain at 3 T. In this study, we investigated accuracy reproducibility short‐TE measurements GABA T using both simulations experiments. LCModel analysis was performed on large number simulated spectra with known metabolite input concentrations. Simulated were generated range spectral linewidths signal‐to‐noise ratios to investigate effect varying experimental...
Gilles de la Tourette syndrome is a hereditary, neuropsychiatric movement disorder with reported abnormalities in the neurotransmission of dopamine and γ-aminobutyric acid (GABA). Spatially focalized alterations excitatory, inhibitory modulatory neurochemical ratios within specific functional subdivisions basal ganglia, may lead to expression diverse motor non-motor features as manifested syndrome. Current treatment strategies are often unsatisfactory thus provoking need for further...
To prospectively compare the black-blood ( BB black blood ) imaging efficiency of a delay alternating with nutation for tailored excitation DANTE preparation module conventional double inversion-recovery DIR inversion recovery and motion-sensitive driven equilibrium MSDE modules to introduce new three-dimensional 3D T1-weighted magnetic resonance (MR) sequence.Carotid artery wall was performed in 10 healthy volunteers 15 patients accordance an institutional review board-approved protocol....
Background Visual aura is present in about one-third of migraine patients and triggering by bright or flickering lights frequently reported. Method Using with visual patients, we investigated the neurochemical profile cortex using magnetic resonance spectroscopy. Specifically, glutamate/creatine GABA/creatine ratios were quantified occipital female patients. Results GABA levels lower than that controls. Glutamate but not controls, correlated blood-oxygenation-level-dependent (BOLD) signal...
Right brain injury causes visual neglect - lost awareness of left space. During prism adaptation therapy, patients adapt to a rightward optical shift by recalibrating right arm movements leftward. This can improve neglect, but the benefit single session is transient (~1 day). Here we show that tonic disinhibition motor cortex during enhances consolidation, stabilizing both sensorimotor and cognitive after-effects. In three longitudinal patient case series, just 20 min combined...