Research Repository

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Updating dynamic noise models with moving magnetoencephalographic (MEG) systems (2019)
Journal Article
Lopez, J. D., Tierney, T. M., Sucerquia, A., Valencia, F., Holmes, N., Mellor, S., …Barnes, G. R. (2019). Updating dynamic noise models with moving magnetoencephalographic (MEG) systems. IEEE Access, 7(1), 10093-10102. doi:10.1109/access.2019.2891162

Optically pumped magnetometers have opened many possibilities for the study of human brain function using wearable moveable technology. In order to fully exploit this capability, a stable low-field environment at the sensors is required. One way to a... Read More

Frequency difference mapping applied to the corpus callosum at 7T (2018)
Journal Article
Tendler, B. C., & Bowtell, R. (2018). Frequency difference mapping applied to the corpus callosum at 7T. Magnetic Resonance in Medicine, doi:10.1002/mrm.27626

Purpose: Frequency difference mapping (FDM) is a phase processing technique which characterises the non-linear temporal evolution of the phase of gradient echo signals. Here, a novel FDM processing algorithm is introduced, which is shown to reveal in... Read More

Exploring the relative efficacy of motion artefact correction techniques for EEG data acquired during simultaneous fMRI (2018)
Journal Article
Alexander, D. J., Smith, J. A., Spencer, G. S., Jorge, J., Bowtell, R., & Mullinger, K. J. (2018). Exploring the relative efficacy of motion artefact correction techniques for EEG data acquired during simultaneous fMRI. Human Brain Mapping, doi:10.1002/hbm.24396

Simultaneous EEG-fMRI allows multi-parametric characterisation of brain function, in principle enabling a more complete understanding of brain responses; unfortunately the hostile MRI environment severely reduces EEG data quality. Simply eliminating... Read More

Cognitive neuroscience using wearable magnetometer arrays: non-invasive assessment of language function (2018)
Journal Article
Tierney, T. M., Holmes, N., Meyer, S. S., Boto, E., Roberts, G., Leggett, J., …Barnes, G. R. (2018). Cognitive neuroscience using wearable magnetometer arrays: non-invasive assessment of language function. NeuroImage, 181, (513-520). doi:10.1016/j.neuroimage.2018.07.035. ISSN 1053-8119

Recent work has demonstrated that Optically Pumped Magnetometers (OPMs) can be utilised to create a wearable Magnetoencephalography (MEG) system that is motion robust. In this study, we use this system to map eloquent cortex using a clinically valida... Read More

A bi-planar coil system for nulling background magnetic fields in scalp mounted magnetoencephalography (2018)
Journal Article
Holmes, N., Leggett, J., Boto, E., Roberts, G., Hill, R. M., Tierney, T. M., …Bowtell, R. (2018). A bi-planar coil system for nulling background magnetic fields in scalp mounted magnetoencephalography. NeuroImage, 181, (760-774). doi:10.1016/j.neuroimage.2018.07.028. ISSN 1053-8119

Small, commercially-available Optically Pumped Magnetometers (OPMs) can be used to construct a wearable Magnetoencephalography (MEG) system that allows large head movements to be made during recording. The small dynamic range of these sensors however... Read More

Quantifying MRI frequency shifts due to structures with anisotropic magnetic susceptibility using pyrolytic graphite sheet (2018)
Journal Article
Cronin, M., & Bowtell, R. W. (2018). Quantifying MRI frequency shifts due to structures with anisotropic magnetic susceptibility using pyrolytic graphite sheet. Scientific Reports, 8, doi:10.1038/s41598-018-24650-2. ISSN 2045-2322

Magnetic susceptibility is an important source of contrast in magnetic resonance imaging (MRI), with spatial variations in the susceptibility of tissue affecting both the magnitude and phase of the measured signals. This contrast has generally been i... Read More

Moving magnetoencephalography towards real-world applications with a wearable system (2018)
Journal Article
Boto, E., Holmes, N., Leggett, J., Roberts, G., Shah, V., Meyer, S. S., …Brookes, M. J. (2018). Moving magnetoencephalography towards real-world applications with a wearable system. Nature, 555, doi:10.1038/nature26147. ISSN 0028-0836

Imaging human brain function with techniques such as magnetoencephalography1 (MEG) typically requires a subject to perform tasks whilst their head remains still within a restrictive scanner. This artificial environment makes the technique inaccessibl... Read More

A new generation of magnetoencephalography: room temperature measurements using optically-pumped magnetometers (2017)
Journal Article
Boto, E., Meyer, S. S., Shah, V., Alem, O., Knappe, S., Kruger, P., …Brookes, M. J. (2017). A new generation of magnetoencephalography: room temperature measurements using optically-pumped magnetometers. NeuroImage, 149, doi:10.1016/j.neuroimage.2017.01.034. ISSN 1053-8119

Advances in the field of quantum sensing mean that magnetic field sensors, operating at room temperature, are now able to achieve sensitivity similar to that of cryogenically cooled devices (SQUIDs). This means that room temperature magnetoencephalog... Read More

Histological basis of laminar MRI patterns in high resolution images of fixed human auditory cortex (2016)
Journal Article
Wallace, M. N., Cronin, M. J., Bowtell, R. W., Scott, I., Palmer, A. R., & Gowland, P. A. (2016). Histological basis of laminar MRI patterns in high resolution images of fixed human auditory cortex. Frontiers in Neuroscience, 10, doi:10.3389/fnins.2016.00455. ISSN 1662-4548

Functional magnetic resonance imaging (fMRI) studies of the auditory region of the temporal lobe would benefit from the availability of image contrast that allowed direct identification of the primary auditory cortex, as this region cannot be accurat... Read More

On the potential of a new generation of magnetometers for MEG: a beamformer simulation study (2016)
Journal Article
Boto, E., Bowtell, R. W., Kruger, P., Fromhold, T. M., Morris, P. G., Meyer, S. S., …Brookes, M. J. (2016). On the potential of a new generation of magnetometers for MEG: a beamformer simulation study. PLoS ONE, 11(8), doi:10.1371/journal.pone.0157655. ISSN 1932-6203

Magnetoencephalography (MEG) is a sophisticated tool which yields rich information on the spatial, spectral and temporal signatures of human brain function. Despite unique potential, MEG is limited by a low signal-to-noise ratio (SNR) which is caused... Read More

The UK National Quantum Technology Hub in Sensors and Metrology (2016)
Book
Bongs, K., Boyer, V., Cruise, M., Freise, A., Holynski, M., Hughes, J., …John, P. (2016). The UK National Quantum Technology Hub in Sensors and Metrology. In J. Stuhler, & A. J. Shields (Eds.), Quantum opticsSPIE. doi:10.1117/12.2232143

The UK National Quantum Technology Hub in Sensors and Metrology is one of four flagship initiatives in the UK National of Quantum Technology Program. As part of a 20-year vision it translates laboratory demonstrations to deployable practical devices,... Read More

Effects of white matter microstructure on phase and susceptibility maps (2015)
Journal Article
Wharton, S., & Bowtell, R. W. (in press). Effects of white matter microstructure on phase and susceptibility maps. Magnetic Resonance in Medicine, 173(3), doi:10.1002/mrm.25189. ISSN 0740-3194

Purpose: To investigate the effects on quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI) of the frequency variation produced by the microstructure of white matter (WM). Methods: The frequency offsets in a WM tissue... Read More