Brain Imaging
EIT has been suggested as a basis for brain imaging to enable the detection and monitoring of cerebral ischemia and haemorrhage, epileptic foci localization, together with research into normal brain function and neuronal activity.
In this use EIT depends upon applying low frequency currents above the skull that are around <100 Hz since during neuronal rest at this frequency these currents remain in the extracellular space unable enter into the intracellular space within neurons. However when a neuron makes an action potential or depolarization, the resistance of its membrane preventing this reduces by a factor of 80. When this happens across large numbers of neurons a resistivity change is made of about 0.06–1.7%. This resistivity change provides a means of detecting coherent neuronal activity across large numbers of neurons and so the tomographic imaging of neural activity in the brain.
Unfortunately while such changes are detectable "they are just too small to support reliable production of images." The prospects of using this technique for imaging will depend upon improved signal processing or recording.
Read more about this topic: Electrical Impedance Tomography
Famous quotes containing the word brain:
“Progress celebrates Pyrrhic victories over nature. Progress makes purses out of human skin. When people were traveling in mail coaches, the world got ahead better than it does now that salesmen fly through the air. What good is speed if the brain has oozed out on the way? How will the heirs of this age be taught the most basic motions that are necessary to activate the most complicated machines? Nature can rely on progress; it will avenge it for the outrage it has perpetrated on it.”
—Karl Kraus (1874–1936)