The selfish brain: using high resolution 7 Tesla MRI of the human brain to investigate hypertension

BP is under the control of the brain and in a substantial proportion of patients with intractable hypertension it is thought that problems with the brain's control mechanisms may be the root cause. These central control mechanisms are poorly
understood, since, hitherto, they have been hard to study in humans. The new Cardiff University Brain Research Imaging Centre (CUBRIC) with its ultra-high field (7 Tesla; 7T) MRI system (the third of its kind in the UK) has the tools to address this problem. 7T MRI permits functional magnetic resonance imaging (fMRI) and vascular imaging with high spatial resolution allowing us to visualise, for the first time, key brain regions involved in the control of BP in humans and the small arteries that are seen to alter with age and hypertension, increasing their resistance to flow. The project aims to: Develop the 7T functional and structural vascular imaging protocols and analysis pipelines to reliably map these brain regions and small penetrating arteries that supply deep brain tissue;Demonstrate perturbations to the neural networks involved in blood pressure control in healthy volunteers during normal fluctuations in blood pressure; Characterise neural network function in hypertensive patients in comparison to controls and quantify alterations to vascular resistance that may cause hypertension under the 'selfish brain hypothesis'. The project is interdisciplinary, requiring a student with a physical science background and an interest in applying this to clinical relevant physiological questions. The initial challenges will be to improve image resolution to localise small brainstem nuclei and small vessels. This will involve a good understanding of MRI, signal processing and image registration. Feasibility of this approach has just recently been demonstrated for the investigation of brainstem respiratory control centres at 7T at the University of Oxford. Experimental
approaches will be implemented to map relevant brain networksduring perturbation of BP in healthy volunteers and hypertensives, using simple tasks such as a 'handgrip', which transiently elevates BP.