Professor Kevin Murphy

Professor Kevin Murphy

Wellcome Trust Senior Research Fellow
Head of Brain Imaging Group

School of Physics and Astronomy

A healthy brain is critically dependent on well-functioning blood supply. My research focusses on developing tools to assess the health of ageing blood vessels in the brain using signals from fMRI. This will allow researchers to track deterioration of the vessels as we age and will open the possibility of treating associated brain conditions before they become problematic.

I have a BA in Theoretical Physics, a MSc in High Performance Computing and was awarded my PhD in NeuroImaging Methods in 2005 by Trinity College Dublin. My first post-doctoral position was at the Section on Functional Imaging Methods, National Institutes of Health in Bethesda, Maryland, USA. In 2008, I moved to the Cardiff University Brain Research Imaging Centre (CUBRIC) to work on a Pfizer-sponsored project to improve the interpretability of human pharmacological fMRI. I was awarded a Research Career Development Fellowship in 2010 to remain at CUBRIC to investigate age-related vascular influences on neurovascular coupling. I am currently Professor of Brain Imaging in the School of Physics and Astronomy, CUBRIC, Cardiff University where I am Head of the recently-formed Brain Imaging Group. Funded by a Wellcome Trust Senior Research Fellowship, my research focuses on developing MRI-based tools to assess the health of the brain’s blood vessels during ageing and disease.

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Between 2010 and 2015, I held a Research Career Development Fellowship (RCDF), awarded by the Wellcome Trust. With my RCDF, I aimed to relate fMRI signals more directly to neural activity by removing cerebrovascular confounds. My first RCDF studies focussed on removing physiological confounds to reveal neural activity-related signals with breath-hold techniques. I helped develop a technique to quantify absolute oxygen consumption; an estimate of energy requirements during baseline neural activity.

My group has since shifted its research focus to assessing cerebrovascular function using these "confounds". We developed a reliable method to measure cerebrovascular reactivity (CVR) in clinical populations and used it to assess CVR recovery after stroke . We have established the link between blood pressure and BOLD signals, demonstrating that cerebral autoregulation is measurable with fMRI. To this end, we have developed an MR-compatible lower body negative pressure (LBNP) device and have demonstrated differential changes in tone along the vascular tree to the challenge.

We have demonstrated that for every neural network, a similar vascular network exists supporting the hypothesis that local vessels and neurons should be considered single functional units. We have shown that current measures of neurovascular coupling are dependent on baseline CBF, prompting a radical rethink of the mechanisms involved. With magenetoencaphalography (MEG), we have shown that neuronal oscillatory power is intimately linked with fluctuations in arterial CO2 concentrations during spontaneous breathing.

My current research program is funded by a Wellcome Trust Senior Research Fellowship, started in Sept 2016. In an ageing population, neurological problems related to control of brain blood flow are increasing, generating an unsustainable socioeconomic burden. During my SRF, I plan to develop a pragmatic fMRI-based tool to assess the health of the brain's blood vessels. This will improve understanding of normal brain physiology, opening opportunities to track deterioration of cerebrovascular health during ageing, allowing early intervention in neurological disorders.

FMRI is an ideal method to achieve this vision. The key goal is to provide researchers and clinicians with fMRI tools to assess brain vascular health. Localised brain blood flow is mainly controlled by smooth muscles around the arterioles. We will quantify the health of vessel function by measuring changes in arteriolar blood volume during cerebrovascular processes (autoregulation/reactivity) by developing direct and indirect MRI measures of such function. The indirect measure will combine a comprehensive cerebrovascular function model with widely-available, non-specialised BOLD fMRI scans, helping to maximise accessibility of the technique. Age and disease-related changes in this cerebrovascular measure will be investigated. By providing a new window into cerebrovascular health, this tool aims to help researchers mitigate neurological dysfunction in an ageing population.