Background. Electrical Impedance Tomography is a new medical imaging method which enables images of the internal electrical impedance of a subject to be produced with arrays or external electrodes. Originally developed for imaging lung ventilation, it has unique potential in imaging the brain and nerves, where it can provide images of fast electrical activity over milliseconds not possible by any other method. Its applications in Neuroscience have been pioneered by a multidisciplinary bioengineering/neurophysiology research group in Medical Physics at University College London, headed by Prof. David Holder, a Neurologist and Biophysicist, and Dr. Kirill Aristovich, a Bioengineer. Fast neural EIT has been successfully developed for imaging action potentials within peripheral nerve, and for imaging evoked activity in the brain, both over milliseconds. It can also image slower changes over seconds, similar to fMRI. The instrumentation currently resembles an EEG system, with benchtop hardware similar to a small-form PC (2). This links to flexible silicone rubber electrode mats placed surgically around nerves or on the brain (1,7). Images are acquired by averaging over a few minutes in response to a repeated stimulus such as a flashing light for the brain or electrical stimulus for nerve. Resulting images have a resolution of 1 msec in time and <0.2 mm in space in peripheral nerves (5) or the brain (3,6). The group has a wide range of skills, in biology and medicine for experimental design and analysis, electronic and mechanical engineering for instrumentation development, maths for image reconstruction, physics for experiments and modelling, and chemical engineering for electrode design. The group has good links with industry. The nerve application is in collaboration with GSK and Google Health, with the intended application of enabled more targeted stimulation in “Electroceuticals”- treatment of many diseases by electrical stimulation of autonomic nerves. Brain applications are in collaboration with companies in Neural Engineering, developing magnetic brain sensors and microelectrodes for recording brain and nerve function, and miniaturising the hardware with a major international Electronics manufacturer.
Project work. This project is to develop the technology to provide an external cycle helmet like electrode array, improve sensitivity and coverage of the method, and develop implantable miniature instrumentation. The technology will be progressively tested and refined in saline filled tanks, physiological studies and human subjects. Students are sought with the above backgrounds and will usually work in a team according to their expertise; full training will be given in other relevant disciplines. They will incorporate the above technologies into EIT, adapt methods for image reconstruction and test and refine these in studies in experimental studies and human subjects. The deliverables will be :
- New methods for imaging brain and nerve function, such as a helmet for imaging in acute stroke or tracing the onset zone in epileptic seizures, or an implanted device for treating heart failure by electrical stimulation of the vagus nerve in the neck
- Objective trials in physiological studies or human subjects of their efficacy in imaging activity in brain or nerve
- Objective trials in imaging and treating diseases such as epilepsy or heart failure by targeted electrical stimulation.
Applications are sought from outstanding candidates with a minimum of an upper-second-class Honours degree or an MSc in biology, medicine, engineering, physics, maths, materials science or a related subject. It will suit candidates who like a challenge and to work in a multidisciplinary team. This research will be based in Medical Physics at UCL but be jointly with industry and candidates should be interested in the industrial collaboration.
To make an application, please email your CV and a covering letter to: Prof. David Holder ([email protected]
) explaining your interests, and research experience.
1) Aristovich, K. Y., Packham, B. C., Koo, H., dos Santos, G. S., McEvoy, A., & Holder, D. S. (2016). Imaging fast electrical activity in the brain with electrical impedance tomography. NEUROIMAGE, 124, 204-213. doi:10.1016/j.neuroimage.2015.08.071
2) Avery, J. P., Dowrick, T., Faulkner, A., Goren, N., & Holder, D. (2017). A Versatile and Reproducible Multi-Frequency Electrical Impedance Tomography System. Sensors. Sensors (Basel). 2017 Jan 31;17(2). pii: E280. doi: 10.3390/s17020280.
3) Faulkner, M., Hannan, S., Aristovich, K., Avery, J., & Holder, D. (2018). Feasibility of imaging evoked activity throughout the rat brain using electrical impedance tomography. NeuroImage, 178, 1-10. doi:10.1016/j.neuroimage.2018.05.022
4) Witkowska-Wrobel, A., Aristovich, K., Faulkner, M., Avery, J., & Holder, D. (2018). Feasibility of imaging epileptic seizure onset with EIT and depth electrodes. NeuroImage, 173, 311-321. doi:10.1016/j.neuroimage.2018.02.056
5) Aristovich K, Donegá M, Blochet C, Avery J, Hannan S, Chew DJ, Holder D. (2018) Imaging fast neural traffic at fascicular level with electrical impedance tomography: proof of principle in rat sciatic nerve. J Neural Eng. 2018 Oct;15(5):056025. doi: 10.1088/1741-2552/aad78e. Epub 2018 Aug 2. PubMed PMID:30070261.
6) Hannan, S., Faulkner, M., Aristovich, K., Avery, J., Walker, M., & Holder, D. (2018). Imaging fast electrical activity in the brain during ictal epileptiform discharges with electrical impedance tomography. NeuroImage. Clinical, 20, 674-684. Advance online publication. doi:10.1016/j.nicl.2018.09.004
7) Chapman, C. A. R., Aristovich, K., Donega, M., Fjordbakk, C. T., Stathopoulou, T. -. R., Viscasillas, J., Holder, D. (2019). Electrode fabrication and interface optimization for imaging of evoked peripheral nervous system activity with electrical impedance tomography (EIT). JOURNAL OF NEURAL ENGINEERING, 16 (1), ARTN 016001. doi:10.1088/1741-2552/aae868
8) Aristovich K, Donega M, Fjordbakk C, Tarotin I, Chapman C, Viscasillas J, Stathopoulou T, Crawford A, Chew D, Perkins J, Holder D. (2019) Complete optimisation and in-vivo validation of a spatially selective multielectrode array for vagus nerve neuromodulation eprint arXiv:1903.12459. URL - https://ui.adsabs.harvard.edu/abs/2019arXiv190312459A