Functional Neuroimaging: a window on the working human brain 23/05/2019 Functional Neuroimaging: a window on the working human brain Dr. Matt Brookes Sir Peter Mansfield Magnetic Resonance Centre

MRI in Nottingham 1978 2011 MRI now a standard diagnostic tool in hospitals worldwide ~60 million scans performed every year

MRI in Nottingham Professor Sir Peter Mansfield and Professor Paul Lauterbur shared the Nobel prize for physiology or medicine in 2003

MRI in Nottingham 0.1 T: 1977 7 T: 2011

Structural imaging at ultra high magnetic field Imaging brain function Overview: Structural imaging at ultra high magnetic field Imaging brain function Functional MRI at 7T Imaging electrical current in the brain Measurements of neurochemistry Conclusions

Structural Imaging Images of the Cerebellum at 1.5 T and 7 T In plane resolution increased from 1mm to 0.4mm

Structural Imaging 3T system 7T system Different relaxation times at 7T means new contrast mechanisms

Functional Imaging Time Functional MRI provides the ability to image human brain function in vivo Time Whole head images are acquired in a fraction of a second. This enables rapid, real time imaging of the entire brain. We detect small changes in blood flow, volume and oxygenation. Therefore we can image brain function.

Functional Imaging DIGIT NUMBER Higher contrast in fMRI at 7T enables functional mapping with high spatial resolution ~1mm Here we show functional changes due to finger movement

Functional Imaging BLOOD VESSELS NEURON

Functional Imaging BLOOD VESSELS NEURON Blood flow in the brain can be measured using functional MRI BLOOD VESSELS NEURON We want to measure electrical activity in neurons

Magnetoencephalography A set of 275 magnetic field detectors placed around the head. Sensors can measure field changes to an accuracy of ~10fT Measure the magnetic fields induced outside the head by flow of current through electrical cells in the brain

Magnetoencephalography Technical Challenge: Measure magnetic field outside the head, and turn it into an image of current density in the brain MEG Beamformer Projects sensor space data into source space and allows imaging of electrical brain activity

Magnetoencephalography Change in brain current induced by a moving visual stimulus (rotating wedge)

Magnetoencephalography BOLD fMRI MEG -ERS The MEG signal is rich in information with a range of detectable The time scale of the electrical effects is at the ms level whereas BOLD ~ 5-8s Nevertheless BOLD and neuro-electrical effects are closely related MEG mirrors invasive recordings made in animal brains MEG -ERD MEG -ERS

Functional Imaging BLOOD VESSELS NEUROCHEMISTRY NEURON Blood flow in the brain can be measured using functional MRI BLOOD VESSELS Can we gain insight into neurochemistry? NEUROCHEMISTRY NEURON Measure electrical activity using MEG

MR Spectroscopy In MRI we measure the distribution of free water in the body However, MR is sensitive to the molecular surroundings of water molecules and so measurements can be chemically specific MR spectroscopy therefore enables measurement of the concentration of different neuro-chemicals is specific brain regions Example of MRS showing metabolite concentrations in the visual cortex

Our work has begun to use MRS to investigate the neurochemical origin of electrical brain activity We have shown significant correlations between the concentration of neurotransmitters and the frequency of electrical signals These exciting new results have the potential to explain both normal brain processes, and how they are perturbed by disease.

Conclusions Structural imaging has been revolutionised at 7T with increased spatial resolution and novel contrast mechanisms enabling new clinical insight. Functional neuroimaging offers exciting insights in to the internal workings of the human brain. We can measure blood flow, electrical activity and neurochemistry non-invasively using fMRI, MEG and MRS.

Conclusions cont… Neuroimaging is multi-disciplinary and success requires collaboration between Physicists, Statisticians, Engineers, Neuroscientists, Medics, Psychiatrists, Psychologists… Nottingham’s continued success in this area is based on academic excellence across multiple subject areas Continued development and clinical application of neuroimaging technology will ensure that the next 30 years is even more exciting that the last 30 years!!

THANKYOU! Prof. Sir Peter Mansfield, Prof. Peter Morris, Prof. Richard Bowtell, Prof. Penny Gowland, Dr. Sue Francis and all colleagues at the Sir Peter Mansfield Magnetic Resonance Centre. Thanks also to the BBC for allowing us to show the tomorrows world clip, which was first broadcast in 1978