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A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field (2016)
Journal Article
Cronin, M. J., Wharton, S., Al-Radaideh, A., Constantinescu, C., Evangelou, N., Bowtell, R. W., & Gowland, P. A. (2016). A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field. Magnetic Resonance Materials in Physics, Biology and Medicine, 29(3), 543-557. https://doi.org/10.1007/s10334-016-0560-5

Objective The aim of this study was to compare the use of high-resolution phase and QSM images acquired at ultra-high field in the investigation of multiple sclerosis (MS) lesions with peripheral rings, and to discuss their usefulness for drawing... Read More about A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field.

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.

Functional quantitative susceptibility mapping (fQSM) (2014)
Journal Article
Balla, D. Z., Sánchez-Panchuelo, R., Wharton, S. J., Hagberg, G. E., Scheffler, K., Francis, S. T., & Bowtell, R. (2014). Functional quantitative susceptibility mapping (fQSM). NeuroImage, 100, 112-124. https://doi.org/10.1016/j.neuroimage.2014.06.011

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is a powerful technique, typically based on the statistical analysis of the magnitude component of the complex time-series. Here, we additionally interrogated the p... Read More about Functional quantitative susceptibility mapping (fQSM).

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.

Event-related fMRI at 7T reveals overlapping cortical representations for adjacent fingertips in S1 of individual subjects (2013)
Journal Article
Besle, J., Sánchez-Panchuelo, R., Bowtell, R., Francis, S., & Schluppeck, D. (2014). Event-related fMRI at 7T reveals overlapping cortical representations for adjacent fingertips in S1 of individual subjects. Human Brain Mapping, 35(5), 2027-2043. https://doi.org/10.1002/hbm.22310

Recent fMRI studies of the human primary somatosensory cortex have been able to differentiate the cortical representations of different fingertips at a single-subject level. These studies did not, however, investigate the expected overlap in cortical... Read More about Event-related fMRI at 7T reveals overlapping cortical representations for adjacent fingertips in S1 of individual subjects.

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
Sánchez-Panchuelo, R., Besle, J., Mougin, O., Gowland, P., Bowtell, R., Schluppeck, D., & Francis, S. (2014). Regional structural differences across functionally parcellated Brodmann areas of human primary somatosensory cortex. NeuroImage, 93 Pt 2, 221-230. https://doi.org/10.1016/j.neuroimage.2013.03.044

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.