Imaging fast electrical activity in the brain with electrical impedance tomography.
Imaging of neuronal depolarization in the brain is a major goal in neuroscience, but no technique currently exists that could image neural activity over milliseconds throughout the whole brain. Electrical impedance tomography (EIT) is an emerging medical imaging technique which can produce tomographic images of impedance changes with non-invasive surface electrodes. We report EIT imaging of impedance changes in rat somatosensory cerebral cortex with a resolution of 2ms and <200μm during evoked potentials using epicortical arrays with 30 electrodes. Images were validated with local field potential recordings and current source-sink density analysis. Our results demonstrate that EIT can image neural activity in a volume 7×5×2mm in somatosensory cerebral cortex with reduced invasiveness, greater resolution and imaging volume than other methods. Modeling indicates similar resolutions are feasible throughout the entire brain so this technique, uniquely, has the potential to image functional connectivity of cortical and subcortical structures.
Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, UK. Electronic address: k.aristovich@ucl.ac.uk.
Kirill Y
KY
Aristovich
Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, UK.
Brett C
BC
Packham
Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, UK.
Hwan
H
Koo
Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, UK.
Gustavo Sato Dos
GSD
Santos
National Hospital for Neurology and Neurosurgery, University College London Hospitals, Queen Square, London, WC1N 3BG, UK.
Andy
A
McEvoy
Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, UK.
David S
DS
Holder
D000818:Animals; D058256:Brain Waves; D017097:Electric Impedance; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000379:methods*; D005073:Evoked Potentials, Somatosensory; D005260:Female; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008839:Microelectrodes; D008959:Models, Neurological; D051381:Rats; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D013003:Somatosensory Cortex / Q000502:physiology*; D014054:Tomography / Q000379:methods*; D055698:Touch Perception / Q000502:physiology*