![Christopher Evans B.Sc (Bristol) Ph.D. (Exeter) CPhys](https://profiles-cardiff.imgix.net/attachments/5656?w=200&h=200&auto=format&crop=faces&fit=crop&q=90")
Dr Christopher Evans
B.Sc (Bristol) Ph.D. (Exeter) CPhys
MRI Lab Manager
Overview
Research summary
As the Chief Physicist of the Magnetic Resonance lab in CUBRIC, I am responsible for the optimisation of our 3 Tesla MR system for use as a tool for neuroimaging research, for example by the implementation of novel pulse sequences. This role also involves advising on experimental design and analysis across the whole range of MR methods – structural and functional imaging and Spectroscopy.
My research interests include:
MR Spectroscopy
Evaluating the robustness of GABA measurement in vivo.
The optimisation of analysis methods for GABA spectra, and the development of a toolkit for the analysis of GABA data (Gannet)
TMS-MRI.
Working on hardware improvements to allow the integration of transcranial magnetic stimulation into the MR environment for simultaneous TMS and functional MRI.
Publication
2024
- Afzali, M. et al. 2024. In vivo diffusion MRI of the human heart using a 300 mT/m gradient system. Magnetic Resonance in Medicine 92(3), pp. 1022-1034. (10.1002/mrm.30118)
2023
- Merritt, K. et al. 2023. The impact of cumulative obstetric complications and childhood trauma on brain volume in young people with psychotic experiences. Molecular Psychiatry 28, pp. 3688-3697. (10.1038/s41380-023-02295-6)
2022
- Shastin, D. et al. 2022. Surface-based tracking for short association fibre tractography. NeuroImage 260, article number: 119423. (10.1016/j.neuroimage.2022.119423)
- Keenan, B. E., Lacan, F., Cooper, A., Evans, S. L. and Evans, J. 2022. MRI safety, imaging artefacts, and grid distortion evaluated for FFP3 respiratory masks worn throughout the COVID-19 pandemic. Clinical Radiology 77(8), pp. e660-e666. (10.1016/j.crad.2022.05.001)
- Molendowska, M. et al. 2022. Physiological effects of human body imaging with 300 mT/m gradients. Magnetic Resonance in Medicine 87(5), pp. 2512-2520. (10.1002/mrm.29118)
2021
- Costigan, A. G., Umla-Runge, K., Evans, C. J., Raybould, R., Graham, K. S. and Lawrence, A. D. 2021. Evidence against altered excitatory/inhibitory balance in the posteromedial cortex of young adult APOE E4 carriers: a resting state 1H-MRS study. Neuroimage: Reports 1(4), article number: 100059. (10.1016/j.ynirp.2021.100059)
- Koller, K. et al. 2021. MICRA: Microstructural Image Compilation with Repeated Acquisitions. NeuroImage 225, article number: 117406. (10.1016/j.neuroimage.2020.117406)
2020
- Maizey, L., Evans, C. J., Muhlert, N., Vergruggen, F., Chambers, C. D. and Allen, C. P. G. 2020. Cortical and subcortical functional specificity associated with response inhibition. NeuroImage 220, article number: 117110. (10.1016/j.neuroimage.2020.117110)
- Patel, Y., Shin, J., Drakesmith, M., Evans, J., Pausova, Z. and Paus, T. 2020. Virtual histology of multi-modal magnetic resonance imaging of cerebral cortex in young men. NeuroImage 218, article number: 116968. (10.1016/j.neuroimage.2020.116968)
- Sharp, T. H. et al. 2020. Population neuroimaging: generation of a comprehensive data resource within the ALSPAC pregnancy and birth cohort. Wellcome Open Research 5, article number: 203. (10.12688/wellcomeopenres.16060.1)
2019
- Costigan, A. G., Umla-Runge, K., Evans, C. J., Hodgetts, C. J., Lawrence, A. D. and Graham, K. S. 2019. Neurochemical correlates of scene processing in the precuneus/posterior cingulate cortex: A multimodal fMRI and 1H-MRS study. Human Brain Mapping 40(10), pp. 2884-2898. (10.1002/hbm.24566)
- Tax, C. M. W. et al. 2019. Cross-scanner and cross-protocol diffusion MRI data harmonisation: A benchmark database and evaluation of algorithms. NeuroImage 195, pp. 285-299. (10.1016/j.neuroimage.2019.01.077)
2018
- Jensen, S. K. et al. 2018. Associations between prenatal, childhood, and adolescent stress and variations in white-matter properties in young men. NeuroImage 182, pp. 389-397. (10.1016/j.neuroimage.2017.10.033)
- Puts, N. A. J. et al. 2018. GABA levels in left and right sensorimotor cortex correlate across individuals. Biomedicines 6(3), article number: 80. (10.3390/biomedicines6030080)
2017
- Harris, A. D. et al. 2017. Normalizing data from GABA-edited MEGA-PRESS implementations at 3 Tesla. Magnetic Resonance Imaging 42, pp. 8-15. (10.1016/j.mri.2017.04.013)
2016
- Mikkelsen, M., Singh, K., Brealy, J., Linden, D. and Evans, C. J. 2016. Quantification of y-aminobutyric acid (GABA) in 1 H MRS volumes composed heterogeneously of grey and white matter. NMR in Biomedicine 29(11), pp. 1644-1655. (10.1002/nbm.3622)
- Poon, C. Y. et al. 2016. Pulmonary arterial response to hypoxia in survivors of chronic lung disease of prematurity. Archives of Disease in Childhood-Fetal and Neonatal Edition 101(4), pp. F309-F313. (10.1136/archdischild-2015-309015)
- Carhart-Harris, R. L. et al. 2016. Neural correlates of the LSD experience revealed by multimodal neuroimaging. Proceedings of the National Academy of Sciences 113(17), pp. 4853-4858. (10.1073/pnas.1518377113)
- Mikkelsen, M., Singh, K. D., Sumner, P. and Evans, C. J. 2016. Comparison of the repeatability of GABA-edited magnetic resonance spectroscopy with and without macromolecule suppression. Magnetic Resonance in Medicine 75(3), pp. 946-953. (10.1002/mrm.25699)
2015
- Robson, S. E. et al. 2015. Structural and neurochemical correlates of individual differences in gamma frequency oscillations in human visual cortex. Journal of Anatomy 227(4), pp. 409-417. (10.1111/joa.12339)
- Drakesmith, M. et al. 2015. Schizophrenia-like topological changes in the structural connectome of individuals with subclinical psychotic experiences. Human Brain Mapping 36(7), pp. 2629-2643. (10.1002/hbm.22796)
- Brix, M. K. et al. 2015. Brain MR spectroscopy in autism spectrum disorder - the GABA excitatory/inhibitory imbalance theory revisited. Frontiers in Human Neuroscience 9, article number: 365. (10.3389/fnhum.2015.00365)
2014
- Edden, R. A., Puts, N. A., Harris, A. D., Barker, P. B. and Evans, C. J. 2014. Gannet: a batch-processing tool for the quantitative analysis of gamma-aminobutyric acid-edited MR spectroscopy spectra. Journal of Magnetic Resonance Imaging 40(6), pp. 1445-1452. (10.1002/jmri.24478)
- Harris, A. D. et al. 2014. Impact of frequency drift on gamma-aminobutyric acid-edited MR spectroscopy. Magnetic Resonance in Medicine 72(4), pp. 941-948. (10.1002/mrm.25009)
- Myers, J. F. M., Evans, C. J., Kalk, N. J., Edden, R. A. E. and Lingford-Hughes, A. R. 2014. Measurement of GABA using J-difference edited1H-MRS following modulation of synaptic GABA concentration with tiagabine. Synapse 68(8), pp. 355-362. (10.1002/syn.21747)
- Allen, C. et al. 2014. Enhanced awareness followed reversible inhibition of human visual cortex: a combined TMS, MRS and MEG study. PLoS ONE 9(6), pp. e100350. (10.1371/journal.pone.0100350)
- De Santis, S., Assaf, Y., Evans, C. J. and Jones, D. K. 2014. Improved precision in CHARMED assessment of white matter through sampling scheme optimization and model parsimony testing. Magnetic Resonance in Medicine 71(2), pp. 661-671. (10.1002/mrm.24717)
- Mullins, P. G., McGonigle, D., O'Gorman, R. L., Puts, N., Vidyasagar, R., Evans, C. J. and Edden, R. A. E. 2014. Current practice in the use of MEGA-PRESS spectroscopy for the detection of GABA. NeuroImage 86, pp. 43-52. (10.1016/j.neuroimage.2012.12.004)
2013
- De Santis, S., Evans, C. J. and Jones, D. K. 2013. RAPID: A routine assurance pipeline for imaging of diffusion. Magnetic Resonance in Medicine 70(2), pp. 490-496. (10.1002/mrm.24465)
- Shaw, A. et al. 2013. Marked reductions in visual evoked responses but not y-aminobutyric acid concentrations or y-band measures in remitted depression. Biological Psychiatry 73(7), pp. 691-698. (10.1016/j.biopsych.2012.09.032)
- Harris, A. D. et al. 2013. Temporal dynamics of lactate concentration in the human brain during acute inspiratory hypoxia. Journal of Magnetic Resonance Imaging 37(3), pp. 739-745. (10.1002/jmri.23815)
- Evans, C. J. et al. 2013. Subtraction artifacts and frequency (Mis-)alignment in J-difference GABA editing. Journal of Magnetic Resonance Imaging 38(4), pp. 970-975. (10.1002/jmri.23923)
2012
- Bungert, A., Chambers, C. D., Long, E. and Evans, C. J. 2012. On the importance of specialized radiofrequency filtering for concurrent TMS/MRI. Journal of Neuroscience Methods 210(2), pp. 202-205. (10.1016/j.jneumeth.2012.07.023)
- Diukova, A., Ware, J. J., Smith, J. E., Evans, C. J., Murphy, K., Rogers, P. J. and Wise, R. G. 2012. Separating neural and vascular effects of caffeine using simultaneous EEG-FMRI: Differential effects of caffeine on cognitive and sensorimotor brain responses. NeuroImage 62(1), pp. 239-249. (10.1016/j.neuroimage.2012.04.041)
- Keedwell, P. A., Chapman, R. J., Christiansen, K. Y., Richardson, H., Evans, C. J. and Jones, D. K. 2012. Cingulum white matter in young women at risk of depression: The effect of family history and anhedonia. Biological Psychiatry 72(4), pp. 296-302. (10.1016/j.biopsych.2012.01.022)
- Carhart-Harris, R. L. et al. 2012. Implications for psychedelic-assisted psychotherapy: functional magnetic resonance imaging study with psilocybin. The British Journal of Psychiatry 200(3), pp. 238-244. (10.1192/bjp.bp.111.103309)
- Bungert, A., Chambers, C. D., Phillips, M. and Evans, C. J. 2012. Reducing image artefacts in concurrent TMS/fMRI by passive shimming. NeuroImage 59(3), pp. 2167-2174. (10.1016/j.neuroimage.2011.10.013)
- Muthukumaraswamy, S. D., Evans, C. J., Edden, R. A. E., Wise, R. G. and Singh, K. D. 2012. Individual variability in the shape and amplitude of the BOLD-HRF correlates with endogenous GABAergic inhibition. Human Brain Mapping 33(2), pp. 455-465. (10.1002/hbm.21223)
- Carhart-Harris, R. L. et al. 2012. Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin. Proceedings of the National Academy of Sciences of the United States of America 109(6), pp. 2138-2143. (10.1073/pnas.1119598109)
2011
- Puts, N., Edden, R. A. E., Evans, C. J., McGlone, F. and McGonigle, D. 2011. Regionally specific human GABA concentration correlates with tactile discrimination thresholds. Journal of Neuroscience 31(46), pp. 16556-16560. (10.1523/JNEUROSCI.4489-11.2011)
- Murphy, K., Harris, A. D., Diukova, A., Evans, C. J., Lythgoe, D. J., Zelaya, F. and Wise, R. G. 2011. Pulsed arterial spin labeling perfusion imaging at 3 T: estimating the number of subjects required in common designs of clinical trials. Magnetic Resonance Imaging 29(10), pp. 1382-1389. (10.1016/j.mri.2011.02.030)
- Greve, A., Evans, C. J., Graham, K. S. and Wilding, E. L. 2011. Functional specialisation in the hippocampus and perirhinal cortex during the encoding of verbal associations. Neuropsychologia 49(9), pp. 2746-2754. (10.1016/j.neuropsychologia.2011.06.002)
- Boy, F., Evans, C. J., Edden, R. A. E., Lawrence, A. D., Husain, M., Singh, K. D. and Sumner, P. 2011. Dorsolateral Prefrontal γ-Aminobutyric Acid in Men Predicts Individual Differences in Rash Impulsivity. Biological Psychiatry 70(9), pp. 866-872. (10.1016/j.biopsych.2011.05.030)
- Sheppard, A. L., Evans, C. J., Singh, K. D., Wolffsohn, J. S., Dunne, M. C. M. and Davies, L. N. 2011. Three-Dimensional Magnetic Resonance Imaging of the Phakic Crystalline Lens during Accommodation. Investigative Ophthalmology & Visual Science 52(6), pp. 3689-3697. (10.1167/iovs.10-6805)
2010
- Boy, F., Evans, C. J., Edden, R. A. E., Singh, K. D., Husain, M. and Sumner, P. 2010. Individual differences in subconscious motor control predicted by GABA concentration in SMA. Current Biology 20(19), pp. 1779-1785. (10.1016/j.cub.2010.09.003)
- Sumner, P., Edden, R. A. E., Bompas, A., Evans, C. J. and Singh, K. D. 2010. More GABA, less distraction: a neurochemical predictor of motor decision speed. Nature Neuroscience 13(7), pp. 825-827. (10.1038/nn.2559)
- Greve, A., Doidge, A. N., Evans, C. J. and Wilding, E. L. 2010. Functional neuroanatomy supporting judgments of when events occurred. The Journal of Neuroscience 30(20), pp. 7099-7104. (10.1523/JNEUROSCI.0345-10.2010)
- Evans, C. J., McGonigle, D. and Edden, R. A. E. 2010. Diurnal stability of gamma-aminobutyric acid concentration in visual and sensorimotor cortex. Journal of Magnetic Resonance Imaging 31(1), pp. 204-209. (10.1002/jmri.21996)
- Hinton, E., Dymond, S., Von Hecker, U. and Evans, C. J. 2010. Neural correlates of relational reasoning and the symbolic distance effect: involvement of parietal cortex. Neuroscience 168(1), pp. 138-148. (10.1016/j.neuroscience.2010.03.052)
- Edden, R. A. E. et al. 2010. Edited MRS is sensitive to changes in lactate concentration during inspiratory hypoxia. Journal of Magnetic Resonance Imaging 32(2), pp. 320-325. (10.1002/jmri.22233)
2009
- Piechnik, S. K., Evans, C. J., Bary, L. H., Wise, R. G. and Jezzard, P. 2009. Functional changes in CSF volume estimated using measurement of water T2 relaxation. Magnetic Resonance in Medicine 61(3), pp. 579-586. (10.1002/mrm.21897)
2008
- Taylor, M., Murphy, S., Selvaraj, S., Wylezinkska, M., Jezzard, P., Cowen, P. and Evans, C. J. 2008. Differential effects of citalopram and reboxetine on cortical Glx measured with proton MR spectroscopy. Journal of Psychopharmacology 22(5), pp. 473-476. (10.1177/0269881107081510)
- Bhagwagar, Z., Wylezinska, M., Jezzard, P., Evans, C. J., Boorman, E., Matthews, P. M. and Cowen, P. J. 2008. Low GABA concentrations in occipital cortex and anterior cingulate cortex in medication-free, recovered depressed patients. The International Journal of Neuropsychopharmacology 11(2), pp. 255-260. (10.1017/S1461145707007924)
2007
- Bhagwagar, Z. et al. 2007. Reduction in Occipital Cortex γ-Aminobutyric Acid Concentrations in Medication-Free Recovered Unipolar Depressed and Bipolar Subjects. Biological Psychiatry 61(6), pp. 806-812. (10.1016/j.biopsych.2006.08.048)
2006
- Selvaraj, S., Wylezinska, M., Evans, C. J., Jezzard, P., Matthews, P. M. and Cowen, P. J. 2006. Tryptophan depletion does not lower brain GABA levels in healthy volunteers [Letter]. Psychopharmacology 187(1), pp. 131-132. (10.1007/s00213-006-0407-2)
- Clare, S., Evans, C. J. and Jezzard, P. 2006. Requirements for room temperature shimming of the human brain. Magnetic Resonance in Medicine 55(1), pp. 210-214. (10.1002/mrm.20735)
Articles
- Afzali, M. et al. 2024. In vivo diffusion MRI of the human heart using a 300 mT/m gradient system. Magnetic Resonance in Medicine 92(3), pp. 1022-1034. (10.1002/mrm.30118)
- Merritt, K. et al. 2023. The impact of cumulative obstetric complications and childhood trauma on brain volume in young people with psychotic experiences. Molecular Psychiatry 28, pp. 3688-3697. (10.1038/s41380-023-02295-6)
- Shastin, D. et al. 2022. Surface-based tracking for short association fibre tractography. NeuroImage 260, article number: 119423. (10.1016/j.neuroimage.2022.119423)
- Keenan, B. E., Lacan, F., Cooper, A., Evans, S. L. and Evans, J. 2022. MRI safety, imaging artefacts, and grid distortion evaluated for FFP3 respiratory masks worn throughout the COVID-19 pandemic. Clinical Radiology 77(8), pp. e660-e666. (10.1016/j.crad.2022.05.001)
- Molendowska, M. et al. 2022. Physiological effects of human body imaging with 300 mT/m gradients. Magnetic Resonance in Medicine 87(5), pp. 2512-2520. (10.1002/mrm.29118)
- Costigan, A. G., Umla-Runge, K., Evans, C. J., Raybould, R., Graham, K. S. and Lawrence, A. D. 2021. Evidence against altered excitatory/inhibitory balance in the posteromedial cortex of young adult APOE E4 carriers: a resting state 1H-MRS study. Neuroimage: Reports 1(4), article number: 100059. (10.1016/j.ynirp.2021.100059)
- Koller, K. et al. 2021. MICRA: Microstructural Image Compilation with Repeated Acquisitions. NeuroImage 225, article number: 117406. (10.1016/j.neuroimage.2020.117406)
- Maizey, L., Evans, C. J., Muhlert, N., Vergruggen, F., Chambers, C. D. and Allen, C. P. G. 2020. Cortical and subcortical functional specificity associated with response inhibition. NeuroImage 220, article number: 117110. (10.1016/j.neuroimage.2020.117110)
- Patel, Y., Shin, J., Drakesmith, M., Evans, J., Pausova, Z. and Paus, T. 2020. Virtual histology of multi-modal magnetic resonance imaging of cerebral cortex in young men. NeuroImage 218, article number: 116968. (10.1016/j.neuroimage.2020.116968)
- Sharp, T. H. et al. 2020. Population neuroimaging: generation of a comprehensive data resource within the ALSPAC pregnancy and birth cohort. Wellcome Open Research 5, article number: 203. (10.12688/wellcomeopenres.16060.1)
- Costigan, A. G., Umla-Runge, K., Evans, C. J., Hodgetts, C. J., Lawrence, A. D. and Graham, K. S. 2019. Neurochemical correlates of scene processing in the precuneus/posterior cingulate cortex: A multimodal fMRI and 1H-MRS study. Human Brain Mapping 40(10), pp. 2884-2898. (10.1002/hbm.24566)
- Tax, C. M. W. et al. 2019. Cross-scanner and cross-protocol diffusion MRI data harmonisation: A benchmark database and evaluation of algorithms. NeuroImage 195, pp. 285-299. (10.1016/j.neuroimage.2019.01.077)
- Jensen, S. K. et al. 2018. Associations between prenatal, childhood, and adolescent stress and variations in white-matter properties in young men. NeuroImage 182, pp. 389-397. (10.1016/j.neuroimage.2017.10.033)
- Puts, N. A. J. et al. 2018. GABA levels in left and right sensorimotor cortex correlate across individuals. Biomedicines 6(3), article number: 80. (10.3390/biomedicines6030080)
- Harris, A. D. et al. 2017. Normalizing data from GABA-edited MEGA-PRESS implementations at 3 Tesla. Magnetic Resonance Imaging 42, pp. 8-15. (10.1016/j.mri.2017.04.013)
- Mikkelsen, M., Singh, K., Brealy, J., Linden, D. and Evans, C. J. 2016. Quantification of y-aminobutyric acid (GABA) in 1 H MRS volumes composed heterogeneously of grey and white matter. NMR in Biomedicine 29(11), pp. 1644-1655. (10.1002/nbm.3622)
- Poon, C. Y. et al. 2016. Pulmonary arterial response to hypoxia in survivors of chronic lung disease of prematurity. Archives of Disease in Childhood-Fetal and Neonatal Edition 101(4), pp. F309-F313. (10.1136/archdischild-2015-309015)
- Carhart-Harris, R. L. et al. 2016. Neural correlates of the LSD experience revealed by multimodal neuroimaging. Proceedings of the National Academy of Sciences 113(17), pp. 4853-4858. (10.1073/pnas.1518377113)
- Mikkelsen, M., Singh, K. D., Sumner, P. and Evans, C. J. 2016. Comparison of the repeatability of GABA-edited magnetic resonance spectroscopy with and without macromolecule suppression. Magnetic Resonance in Medicine 75(3), pp. 946-953. (10.1002/mrm.25699)
- Robson, S. E. et al. 2015. Structural and neurochemical correlates of individual differences in gamma frequency oscillations in human visual cortex. Journal of Anatomy 227(4), pp. 409-417. (10.1111/joa.12339)
- Drakesmith, M. et al. 2015. Schizophrenia-like topological changes in the structural connectome of individuals with subclinical psychotic experiences. Human Brain Mapping 36(7), pp. 2629-2643. (10.1002/hbm.22796)
- Brix, M. K. et al. 2015. Brain MR spectroscopy in autism spectrum disorder - the GABA excitatory/inhibitory imbalance theory revisited. Frontiers in Human Neuroscience 9, article number: 365. (10.3389/fnhum.2015.00365)
- Edden, R. A., Puts, N. A., Harris, A. D., Barker, P. B. and Evans, C. J. 2014. Gannet: a batch-processing tool for the quantitative analysis of gamma-aminobutyric acid-edited MR spectroscopy spectra. Journal of Magnetic Resonance Imaging 40(6), pp. 1445-1452. (10.1002/jmri.24478)
- Harris, A. D. et al. 2014. Impact of frequency drift on gamma-aminobutyric acid-edited MR spectroscopy. Magnetic Resonance in Medicine 72(4), pp. 941-948. (10.1002/mrm.25009)
- Myers, J. F. M., Evans, C. J., Kalk, N. J., Edden, R. A. E. and Lingford-Hughes, A. R. 2014. Measurement of GABA using J-difference edited1H-MRS following modulation of synaptic GABA concentration with tiagabine. Synapse 68(8), pp. 355-362. (10.1002/syn.21747)
- Allen, C. et al. 2014. Enhanced awareness followed reversible inhibition of human visual cortex: a combined TMS, MRS and MEG study. PLoS ONE 9(6), pp. e100350. (10.1371/journal.pone.0100350)
- De Santis, S., Assaf, Y., Evans, C. J. and Jones, D. K. 2014. Improved precision in CHARMED assessment of white matter through sampling scheme optimization and model parsimony testing. Magnetic Resonance in Medicine 71(2), pp. 661-671. (10.1002/mrm.24717)
- Mullins, P. G., McGonigle, D., O'Gorman, R. L., Puts, N., Vidyasagar, R., Evans, C. J. and Edden, R. A. E. 2014. Current practice in the use of MEGA-PRESS spectroscopy for the detection of GABA. NeuroImage 86, pp. 43-52. (10.1016/j.neuroimage.2012.12.004)
- De Santis, S., Evans, C. J. and Jones, D. K. 2013. RAPID: A routine assurance pipeline for imaging of diffusion. Magnetic Resonance in Medicine 70(2), pp. 490-496. (10.1002/mrm.24465)
- Shaw, A. et al. 2013. Marked reductions in visual evoked responses but not y-aminobutyric acid concentrations or y-band measures in remitted depression. Biological Psychiatry 73(7), pp. 691-698. (10.1016/j.biopsych.2012.09.032)
- Harris, A. D. et al. 2013. Temporal dynamics of lactate concentration in the human brain during acute inspiratory hypoxia. Journal of Magnetic Resonance Imaging 37(3), pp. 739-745. (10.1002/jmri.23815)
- Evans, C. J. et al. 2013. Subtraction artifacts and frequency (Mis-)alignment in J-difference GABA editing. Journal of Magnetic Resonance Imaging 38(4), pp. 970-975. (10.1002/jmri.23923)
- Bungert, A., Chambers, C. D., Long, E. and Evans, C. J. 2012. On the importance of specialized radiofrequency filtering for concurrent TMS/MRI. Journal of Neuroscience Methods 210(2), pp. 202-205. (10.1016/j.jneumeth.2012.07.023)
- Diukova, A., Ware, J. J., Smith, J. E., Evans, C. J., Murphy, K., Rogers, P. J. and Wise, R. G. 2012. Separating neural and vascular effects of caffeine using simultaneous EEG-FMRI: Differential effects of caffeine on cognitive and sensorimotor brain responses. NeuroImage 62(1), pp. 239-249. (10.1016/j.neuroimage.2012.04.041)
- Keedwell, P. A., Chapman, R. J., Christiansen, K. Y., Richardson, H., Evans, C. J. and Jones, D. K. 2012. Cingulum white matter in young women at risk of depression: The effect of family history and anhedonia. Biological Psychiatry 72(4), pp. 296-302. (10.1016/j.biopsych.2012.01.022)
- Carhart-Harris, R. L. et al. 2012. Implications for psychedelic-assisted psychotherapy: functional magnetic resonance imaging study with psilocybin. The British Journal of Psychiatry 200(3), pp. 238-244. (10.1192/bjp.bp.111.103309)
- Bungert, A., Chambers, C. D., Phillips, M. and Evans, C. J. 2012. Reducing image artefacts in concurrent TMS/fMRI by passive shimming. NeuroImage 59(3), pp. 2167-2174. (10.1016/j.neuroimage.2011.10.013)
- Muthukumaraswamy, S. D., Evans, C. J., Edden, R. A. E., Wise, R. G. and Singh, K. D. 2012. Individual variability in the shape and amplitude of the BOLD-HRF correlates with endogenous GABAergic inhibition. Human Brain Mapping 33(2), pp. 455-465. (10.1002/hbm.21223)
- Carhart-Harris, R. L. et al. 2012. Neural correlates of the psychedelic state as determined by fMRI studies with psilocybin. Proceedings of the National Academy of Sciences of the United States of America 109(6), pp. 2138-2143. (10.1073/pnas.1119598109)
- Puts, N., Edden, R. A. E., Evans, C. J., McGlone, F. and McGonigle, D. 2011. Regionally specific human GABA concentration correlates with tactile discrimination thresholds. Journal of Neuroscience 31(46), pp. 16556-16560. (10.1523/JNEUROSCI.4489-11.2011)
- Murphy, K., Harris, A. D., Diukova, A., Evans, C. J., Lythgoe, D. J., Zelaya, F. and Wise, R. G. 2011. Pulsed arterial spin labeling perfusion imaging at 3 T: estimating the number of subjects required in common designs of clinical trials. Magnetic Resonance Imaging 29(10), pp. 1382-1389. (10.1016/j.mri.2011.02.030)
- Greve, A., Evans, C. J., Graham, K. S. and Wilding, E. L. 2011. Functional specialisation in the hippocampus and perirhinal cortex during the encoding of verbal associations. Neuropsychologia 49(9), pp. 2746-2754. (10.1016/j.neuropsychologia.2011.06.002)
- Boy, F., Evans, C. J., Edden, R. A. E., Lawrence, A. D., Husain, M., Singh, K. D. and Sumner, P. 2011. Dorsolateral Prefrontal γ-Aminobutyric Acid in Men Predicts Individual Differences in Rash Impulsivity. Biological Psychiatry 70(9), pp. 866-872. (10.1016/j.biopsych.2011.05.030)
- Sheppard, A. L., Evans, C. J., Singh, K. D., Wolffsohn, J. S., Dunne, M. C. M. and Davies, L. N. 2011. Three-Dimensional Magnetic Resonance Imaging of the Phakic Crystalline Lens during Accommodation. Investigative Ophthalmology & Visual Science 52(6), pp. 3689-3697. (10.1167/iovs.10-6805)
- Boy, F., Evans, C. J., Edden, R. A. E., Singh, K. D., Husain, M. and Sumner, P. 2010. Individual differences in subconscious motor control predicted by GABA concentration in SMA. Current Biology 20(19), pp. 1779-1785. (10.1016/j.cub.2010.09.003)
- Sumner, P., Edden, R. A. E., Bompas, A., Evans, C. J. and Singh, K. D. 2010. More GABA, less distraction: a neurochemical predictor of motor decision speed. Nature Neuroscience 13(7), pp. 825-827. (10.1038/nn.2559)
- Greve, A., Doidge, A. N., Evans, C. J. and Wilding, E. L. 2010. Functional neuroanatomy supporting judgments of when events occurred. The Journal of Neuroscience 30(20), pp. 7099-7104. (10.1523/JNEUROSCI.0345-10.2010)
- Evans, C. J., McGonigle, D. and Edden, R. A. E. 2010. Diurnal stability of gamma-aminobutyric acid concentration in visual and sensorimotor cortex. Journal of Magnetic Resonance Imaging 31(1), pp. 204-209. (10.1002/jmri.21996)
- Hinton, E., Dymond, S., Von Hecker, U. and Evans, C. J. 2010. Neural correlates of relational reasoning and the symbolic distance effect: involvement of parietal cortex. Neuroscience 168(1), pp. 138-148. (10.1016/j.neuroscience.2010.03.052)
- Edden, R. A. E. et al. 2010. Edited MRS is sensitive to changes in lactate concentration during inspiratory hypoxia. Journal of Magnetic Resonance Imaging 32(2), pp. 320-325. (10.1002/jmri.22233)
- Piechnik, S. K., Evans, C. J., Bary, L. H., Wise, R. G. and Jezzard, P. 2009. Functional changes in CSF volume estimated using measurement of water T2 relaxation. Magnetic Resonance in Medicine 61(3), pp. 579-586. (10.1002/mrm.21897)
- Taylor, M., Murphy, S., Selvaraj, S., Wylezinkska, M., Jezzard, P., Cowen, P. and Evans, C. J. 2008. Differential effects of citalopram and reboxetine on cortical Glx measured with proton MR spectroscopy. Journal of Psychopharmacology 22(5), pp. 473-476. (10.1177/0269881107081510)
- Bhagwagar, Z., Wylezinska, M., Jezzard, P., Evans, C. J., Boorman, E., Matthews, P. M. and Cowen, P. J. 2008. Low GABA concentrations in occipital cortex and anterior cingulate cortex in medication-free, recovered depressed patients. The International Journal of Neuropsychopharmacology 11(2), pp. 255-260. (10.1017/S1461145707007924)
- Bhagwagar, Z. et al. 2007. Reduction in Occipital Cortex γ-Aminobutyric Acid Concentrations in Medication-Free Recovered Unipolar Depressed and Bipolar Subjects. Biological Psychiatry 61(6), pp. 806-812. (10.1016/j.biopsych.2006.08.048)
- Selvaraj, S., Wylezinska, M., Evans, C. J., Jezzard, P., Matthews, P. M. and Cowen, P. J. 2006. Tryptophan depletion does not lower brain GABA levels in healthy volunteers [Letter]. Psychopharmacology 187(1), pp. 131-132. (10.1007/s00213-006-0407-2)
- Clare, S., Evans, C. J. and Jezzard, P. 2006. Requirements for room temperature shimming of the human brain. Magnetic Resonance in Medicine 55(1), pp. 210-214. (10.1002/mrm.20735)
Research
Research topics and related papers
Repeatability of GABA Spectroscopy
There is a significant amount of research demonstrating that the inhibitory neurotransmitter γ-aminobutyric acid (GABA) is a useful biomarker for psychiatric disorders. Recently, work at the School of Psychology at Cardiff has demonstrated that the measurement of GABA concentration in the human brain is sufficiently sensitive to explain individual differences in a variety of behavioural tasks (e.g. Sumner et al, Nature Neuroscience, 2010, Boy et. al. Current Biology, 2010), and in personality traits (Boy et. al. Biological Psychiatry, 2011).
However, the measurement of neurotransmitters using edited MR spectroscopy is inherently insensitive, compared with imaging techniques.
For example, the concentration of GABA is approximately 50,000 times lower than the concentration of water, resulting in longer experiment times and larger voxel sizes than are achievable in imaging experiments. As a result, characterising the robustness of the experiment is very important, particularly as this can vary significantly between brain regions.
Gannet
As part of this research, I have been optimising the analysis method for GABA spectroscopy and, along with Richard Edden (Johns Hopkins University, Baltimore) we have incorporated this into a set of Matlab-based tools (the GABA Analysis Toolkit, "Gannet") which is currently being distributed to collaborating sites, prior to general release [link].
Research collaborators
Fred Boy
Chris Chambers
Richard Edden (Johns Hopkins University, Baltimore)
Derek Jones
Paul Keedwell
David Linden
David McGonigle
Suresh Muthukumaraswamy
Nick Puts (Johns Hopkins University, Baltimore)
Krish Singh
Petroc Sumner
Richard Wise
Biography
Undergraduate education
1995 B.Sc in Physics (University of Bristol)
Postgraduate education
1999 Ph.D. in Physics (University of Exeter)
2002 Chartered Physicist (Institute of Physics)
Employment
2007-present. Chief Physicist, CUBRIC, School of Psychology, Cardiff University, UK
2004-2007. MR Physicist, Department of Psychiatry, University of Oxford, UK
2000-2004. MR System Design Engineer, GE Healthcare, Abingdon, Oxford, UK
1999-2000. MR System Design Engineer, Magnex Scientific, Abingdon, Oxford, UK