A5104157397- Advanced MRI Techniques and Applications
- Optical Imaging and Spectroscopy Techniques
- Functional Brain Connectivity Studies
- Neural dynamics and brain function
- Asthma and respiratory diseases
- Respiratory and Cough-Related Research
- EEG and Brain-Computer Interfaces
- Atomic and Subatomic Physics Research
- Advanced Neuroimaging Techniques and Applications
- Neuroscience and Neuropharmacology Research
- Photoreceptor and optogenetics research
- Pharmaceutical studies and practices
- Cardiovascular Health and Disease Prevention
- Retinal Development and Disorders
- Dysphagia Assessment and Management
- Prostate Cancer Treatment and Research
- Cardiac Imaging and Diagnostics
- MRI in cancer diagnosis
- Heart Rate Variability and Autonomic Control
- Spinal Hematomas and Complications
- Grit, Self-Efficacy, and Motivation
- Child and Animal Learning Development
- Pharmacological Effects and Assays
- Language Development and Disorders
- Inhalation and Respiratory Drug Delivery
Sheffield Teaching Hospitals NHS Foundation Trust
2019-2025
Medical Research Institute of New Zealand
2019-2024
The Christie NHS Foundation Trust
2024
King's College London
2023
University of Manchester
2023
Royal Hallamshire Hospital
2019
University of Sheffield
2000-2009
Macquarie University
2005
GlaxoSmithKline (United Kingdom)
2001
Walton Hospital
1982
Unexpected, biologically salient stimuli elicit a short-latency, phasic response in midbrain dopaminergic (DA) neurons. Although this signal is important for reinforcement learning, the information it conveys to forebrain target structures remains uncertain. One way decode DA would be determine perceptual properties of sensory inputs After local disinhibition superior colliculus anesthetized rats, neurons became visually responsive, whereas visual cortex was ineffective. As primary source...
This article investigates the relation between stimulus-evoked neural activity and cerebral hemodynamics. Specifically, hypothesis is tested that hemodynamic responses can be modeled as a linear convolution of experimentally obtained measures with suitable impulse response function. To obtain range responses, rat whisker pad was stimulated using brief (≤2 seconds) electrical stimuli consisting single pulses (0.3 millisecond, 1.2 mA) combined both at different frequencies in paired-pulse...
The spatial resolution of hemodynamic-based neuroimaging techniques, including functional magnetic resonance imaging, is limited by the degree to which neurons regulate their blood supply on a fine scale. Here we investigated detail neurovascular events with combination high spatiotemporal two-dimensional spectroscopic optical multichannel electrode recordings and cytochrome oxidase histology in rodent whisker barrel field. After mechanical stimulation single whisker, found two spatially...
Abstract Optical imaging slit spectroscopy is a powerful method for estimating quantitative changes in cerebral haemodynamics, such as deoxyhaemoglobin, oxyhaemoglobin and blood volume (Hbr, HbO 2 Hbt, respectively). Its disadvantage that there large loss of spatial data one image dimension used to encode spectral wavelength information. Single optical imaging, on the other hand, produces high‐resolution spatiotemporal maps brain activity, but yields only indirect measures Hbr, Hbt. In this...
Abstract Functional magnetic resonance imaging (fMRI) signal variations are based on a combination of changes in cerebral blood flow (CBF) and volume (CBV), oxygenation. We investigated the relationship between these hemodynamic parameters rodent barrel cortex by performing fMRI concurrently with laser Doppler flowmetry (LDF) or optical spectroscopy (OIS), following whisker stimulation hypercapnic challenge. A difference positions maximum oxygenation level‐dependent (BOLD) CBV was observed...
Grounded in Self-Determination Theory (SDT), we integrate personality traits and basic psychological need frustration to explore relationships between students' 'dark' the core student outcomes of satisfaction, engagement, performance. Using time-separated, multi-source data (N = 330), examined whether perceived mediated effects dark triad (i.e., Psychopathy, Machiavellianism, Narcissism) common variance among triad) upon outcomes. Correlations structural equation models showed that is...
Optical imaging spectroscopy was used to measure the hemodynamic response of somatosensory cortex stimulation whiskers. Responses brief puffs air were compared in anesthetized and unanesthetized rats. The approximately four times larger animal than corresponding animal. In animals, a short-latency (approximately 400 milliseconds) short-duration 300 startle observed. General linear model analysis extract this component from time series, revealed an underlying increase deoxygenated hemoglobin...
The temporal relationship between changes in cerebral blood flow (CBF) and volume (CBV) is important the biophysical modeling interpretation of hemodynamic response to activation, particularly context magnetic resonance imaging oxygen level-dependent signal. measured steady state CBV CBF after hypercapnic challenge. proportional CBFphi has been used extensively literature. Two similar models, Balloon Windkessel , have proposed describe dynamics with respect CBF. In this study, a dynamic...
Abstract The dependency of the blood oxygenation level dependent (BOLD) signal on underlying hemodynamics is not well understood. Building a forward biophysical model this relationship important for quantitative estimation hemodynamic changes and neural activity functional magnetic resonance imaging (fMRI) signals. We have developed general BOLD which can both intra‐ extravascular signals an arbitrary tissue across wide range parameters. was instantiated as look‐up‐table (LuT), verified...
Objective To characterise the self-isolating household units (bubbles) during COVID-19 Alert Level 4 lockdown in New Zealand. Design, setting and participants In this cross-sectional study, an online survey was distributed to a convenience sample via Facebook advertising Medical Research Institute of Zealand’s social media platforms mailing list. Respondents were able share link their own by email. Results collected over 6 days from respondents living Zealand, aged 16 years over. Main...
Recent studies have shown that the haemodynamic responses to brief (<2 secs) stimuli can be well characterised as a linear convolution of neural activity with suitable impulse response. In this paper, we show model cannot predict measurements blood flow longer duration (>2 secs), regardless response function chosen. Modifying scheme nonlinear was found provide good prediction observed data. Whereas several coupling between stimulus input and responses, current modelling uses an input,...
Background Asthma is the most common chronic childhood respiratory condition globally. Inhaled corticosteroid (ICS)–formoterol reliever-based regimens reduce risk of asthma exacerbations compared with conventional short-acting β 2 -agonist (SABA) in adults and adolescents. The current limited evidence for anti-inflammatory reliever therapy children means it unknown whether these findings are also applicable to children. High-quality randomised controlled trials (RCTs) needed. Objective study...
Abstract The relationship between localized changes in brain activity and metabolism, the blood oxygenation level‐dependent (BOLD) signal used functional magnetic resonance imaging studies is not fully understood. One source of complexity that stimulus‐elicited BOLD arise both from oxygen consumption due to increases purely ‘haemodynamic’ such as cerebral flow. It well established robust cortical haemodynamic can be elicited by increasing concentration inspired CO 2 (inducing hypercapnia) it...
Abstract The aim of this study was to determine the extent cortical functional preservation following retinal pigment epithelium (RPE) transplantation in Royal College Surgeons (RCS) rat using single‐wavelength optical imaging and spectroscopy. responses visual stimulation transplanted rats at 6 months post‐transplantation were compared with those from age‐matched untreated dystrophic non‐dystrophic rats. Our results show that evoked both luminance changes pattern stimulation, whereas no...