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All Outputs (59)

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. https://doi.org/10.1016/j.neuroimage.2018.07.028

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 about A bi-planar coil system for nulling background magnetic fields in scalp mounted magnetoencephalography.

Microstructural imaging of the human brain with a ‘super-scanner’: 10 key advantages of ultra-strong gradients for diffusion MRI (2018)
Journal Article
Jones, D., Alexander, D., Bowtell, R. W., Cercignani, M., Dell'Acqua, F., McHugh, D., …Tax, C. (2018). Microstructural imaging of the human brain with a ‘super-scanner’: 10 key advantages of ultra-strong gradients for diffusion MRI. NeuroImage, 182, 8-38. https://doi.org/10.1016/j.neuroimage.2018.05.047

The key component of a microstructural diffusion MRI ‘super-scanner’ is a dedicated high-strength gradient system that enables stronger diffusion weightings per unit time compared to conventional gradient designs. This can, in turn, drastically short... Read More about Microstructural imaging of the human brain with a ‘super-scanner’: 10 key advantages of ultra-strong gradients for diffusion MRI.

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, Article 6259. https://doi.org/10.1038/s41598-018-24650-2

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 about Quantifying MRI frequency shifts due to structures with anisotropic magnetic susceptibility using pyrolytic graphite sheet.

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, 657-661. https://doi.org/10.1038/nature26147

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 about Moving magnetoencephalography towards real-world applications with a wearable system.

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), Article e0157655. https://doi.org/10.1371/journal.pone.0157655

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 about On the potential of a new generation of magnetometers for MEG: A beamformer simulation study.

The UK National Quantum Technologies Hub in sensors and metrology (Keynote Paper) (2016)
Presentation / Conference Contribution
Bongs, K., Boyer, V., Cruise, M., Freise, A., Holynski, M., Hughes, J., Kaushik, A., Lien, Y.-H., Niggebaum, A., Perea-Ortiz, M., Petrov, P., Plant, S., Singh, Y., Stabrawa, A., Paul, D., Sorel, M., Cumming, D., Marsh, J., Bowtell, R. W., Bason, M., …John, P. (2016, April). The UK National Quantum Technologies Hub in sensors and metrology (Keynote Paper). Presented at SPIE Photonics Europe, 2016, Brussels, Belgium

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 about The UK National Quantum Technologies Hub in sensors and metrology (Keynote Paper).

Global signal modulation of single-trial fMRI response variability: effect on positive vs negative BOLD response relationship (2016)
Journal Article
Mayhew, S. D., Mullinger, K. J., Ostwald, D., Porcaro, C., Bowtell, R. W., Bagshaw, A. P., & Francis, S. T. (2016). Global signal modulation of single-trial fMRI response variability: effect on positive vs negative BOLD response relationship. NeuroImage, 133, https://doi.org/10.1016/j.neuroimage.2016.02.077

In functional magnetic resonance imaging (fMRI), the relationship between positive BOLD responses (PBRs) and negative BOLD responses (NBRs) to stimulation is potentially informative about the balance of excitatory and inhibitory brain responses in se... Read More about Global signal modulation of single-trial fMRI response variability: effect on positive vs negative BOLD response relationship.

Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study (2015)
Journal Article
Jung, J., Bungert, A., Bowtell, R., & Jackson, S. R. (2016). Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study. Brain Stimulation, 9(1), 58-64. https://doi.org/10.1016/j.brs.2015.09.008

Background A common control condition for transcranial magnetic stimulation (TMS) studies is to apply stimulation at the vertex. An assumption of vertex stimulation is that it has relatively little influence over on-going brain processes involved in... Read More about Vertex Stimulation as a Control Site for Transcranial Magnetic Stimulation: A Concurrent TMS/fMRI Study.

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), https://doi.org/10.1002/mrm.25189

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 about Effects of white matter microstructure on phase and susceptibility maps.

Evidence that the negative BOLD response is neuronal in origin: a simultaneous EEG–BOLD–CBF study in humans (2014)
Journal Article
Mullinger, K. J., Mayhew, S. D., Bagshaw, A. P., Bowtell, R. W., & Francis, S. T. (2014). Evidence that the negative BOLD response is neuronal in origin: a simultaneous EEG–BOLD–CBF study in humans. NeuroImage, 94, https://doi.org/10.1016/j.neuroimage.2014.02.029

Unambiguous interpretation of changes in the BOLD signal is challenging because of the complex neurovascular coupling that translates changes in neuronal activity into the subsequent haemodynamic response. In particular, the neurophysiological origin... Read More about Evidence that the negative BOLD response is neuronal in origin: a simultaneous EEG–BOLD–CBF study in humans.

Reference layer artefact subtraction (RLAS): A novel method of minimizing EEG artefacts during simultaneous fMRI (2013)
Journal Article
Chowdhury, M. E., Mullinger, K. J., Glover, P., & Bowtell, R. W. (2014). Reference layer artefact subtraction (RLAS): A novel method of minimizing EEG artefacts during simultaneous fMRI. NeuroImage, 84, 307-319. https://doi.org/10.1016/j.neuroimage.2013.08.039

Large artefacts compromise EEG data quality during simultaneous fMRI. These artefact voltages pose heavy demands on the bandwidth and dynamic range of EEG amplifiers and mean that even small fractional variations in the artefact voltages give rise to... Read More about Reference layer artefact subtraction (RLAS): A novel method of minimizing EEG artefacts during simultaneous fMRI.

Poststimulus undershoots in cerebral blood flow and BOLD fMRI responses are modulated by poststimulus neuronal activity (2013)
Journal Article
Mullinger, K. J., Mayhew, S. D., Bagshaw, A. P., Bowtell, R., & Francis, S. T. (2013). Poststimulus undershoots in cerebral blood flow and BOLD fMRI responses are modulated by poststimulus neuronal activity. Proceedings of the National Academy of Sciences, 110(33), https://doi.org/10.1073/pnas.1221287110

fMRI is the foremost technique for noninvasive measurement of human brain function. However, its utility is limited by an incomplete understanding of the relationship between neuronal activity and the hemodynamic response. Though the primary peak of... Read More about Poststimulus undershoots in cerebral blood flow and BOLD fMRI responses are modulated by poststimulus neuronal activity.

Identifying the sources of the pulse artefact in EEG recordings made inside an MR scanner (2013)
Journal Article
Mullinger, K. J., Havenhand, J., & Bowtell, R. W. (2013). Identifying the sources of the pulse artefact in EEG recordings made inside an MR scanner. NeuroImage, 71(1), https://doi.org/10.1016/j.neuroimage.2012.12.070

EEG recordings made during concurrent fMRI are confounded by the pulse artefact (PA), which although smaller than the gradient artefact is often more problematic because of its variability over multiple cardiac cycles. A better understanding of the P... Read More about Identifying the sources of the pulse artefact in EEG recordings made inside an MR scanner.

Regional structural differences across functionally parcellated Brodmann areas of human primary somatosensory cortex (2013)
Journal Article

Ultra-high-field (UHF) MRI is ideally suited for structural and functional imaging of the brain. High-resolution structural MRI can be used to map the anatomical boundaries between functional domains of the brain by identifying changes related to the... Read More about Regional structural differences across functionally parcellated Brodmann areas of human primary somatosensory cortex.

Fiber orientation-dependent white matter contrast in gradient echo MRI (2012)
Journal Article
Wharton, S., & Bowtell, R. W. (2012). Fiber orientation-dependent white matter contrast in gradient echo MRI. Proceedings of the National Academy of Sciences, 109(45), https://doi.org/10.1073/pnas.1211075109

Recent studies have shown that there is a direct link between the orientation of the nerve fibers in white matter (WM) and the contrast observed in magnitude and phase images acquired using gradient echo MRI. Understanding the origin of this link is... Read More about Fiber orientation-dependent white matter contrast in gradient echo MRI.

Motion-related artefacts in EEG predict neuronally plausible patterns of activation in fMRI data (2012)
Journal Article
Jansen, M., White, T. P., Mullinger, K. J., Liddle, E. B., Gowland, P. A., Francis, S. T., …Liddle, P. F. (2012). Motion-related artefacts in EEG predict neuronally plausible patterns of activation in fMRI data. NeuroImage, 59(1), https://doi.org/10.1016/j.neuroimage.2011.06.094

The simultaneous acquisition and subsequent analysis of EEG and fMRI data is challenging owing to increased noise levels in the EEG data. A common method to integrate data from these two modalities is to use aspects of the EEG data, such as the ampli... Read More about Motion-related artefacts in EEG predict neuronally plausible patterns of activation in fMRI data.

Reducing the gradient artefact in simultaneous EEG-fMRI by adjusting the subject’s axial position (2011)
Journal Article
Mullinger, K. J., Yan, W. X., & Bowtell, R. W. (2011). Reducing the gradient artefact in simultaneous EEG-fMRI by adjusting the subject’s axial position. NeuroImage, 54(3), https://doi.org/10.1016/j.neuroimage.2010.09.079

Large artefacts which compromise EEG data quality are generated when electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) are carried out concurrently. The gradient artefact produced by the time-varying magnetic field gradien... Read More about Reducing the gradient artefact in simultaneous EEG-fMRI by adjusting the subject’s axial position.