David Holder

Biography

Prof. Holder’s research group focus on using fast neural electrical impedance tomography (EIT) to image fascicular activity in peripheral nerve.

Electrical Impedance Tomography (EIT) is a new medical imaging technique that offers non-invasive imaging of impedance changes in biological tissue. In nervous tissue, the opening of various ion channels to conduct action potentials produces a decrease in impedance. EIT can be used to image neuronal activity, with microsecond resolution using a cylindrical electrode cuff around the nerve.

The group have demonstrated proof of principle and have been able to image the compound action potential in peroneal and tibial fascicles in rat sciatic nerve with supramaximal stimulation. The goals of their current work are to extend this to image physiological activity in myelinated and unmyelinated fibres, initially in autonomic nerves.  This is part of a broader “Electroceuticals” project in which autonomic nerves are stimulated to treat disease in a novel way.

Personnel in the group working on this :

• David Holder: Professor of Biophysics and Clinical Neurophysiology; Consultant in Clinical Neurophysiology, UCH. http://www.ucl.ac.uk/medphys/contacts/people/dholder
• Kirill Aristovich: Post-doctoral Senior Research Assistant Mechanical Engineer; project leader; EIT nerve in anaesthetised sheep with collaborators at the Royal Veterinary College http://www.ucl.ac.uk/medphys/contacts/research-staff/karistovich
• Tom Dowrick: Post-doctoral Senior Research Assistant Electronic; project leader; electronic hardware development http://www.ucl.ac.uk/medphys/contacts/research-staff/tdowrick
• Martin Smith: Post-doctoral Research Assistant Neuroscience; EIT imaging unmyelinated nerve fibres in crab walking leg nerves
• Chris Chapman: Post-doctoral Research Assistant Electronic Engineering; bioelectrode development
• Ilya Tarotin: PhD student Biophysics;modelling impedance change during activity in peripheral nerve