Controlling Brain Waves

A new study conducted at George Mason University confirms predictions that electrical fields can be used to modify waves traveling through brain tissue. This is perhaps the first example of electric modification of neuronal thresholds to control wave movement. Indeed, it is one of the first times waves have been controlled in an excitable medium through changing thresholds. The researchers begin with a section of rat brain; the tissue consists of 6 layers of 2-dimensional sheets of neurons.

A neural wave is initiated at one end of the network and the signal is observed at the other end. By using electrical fields, the excitability of individual neurons can be modified. Doing this can slow down, speed up, or stop any wave propagating through the sample. Previously neural waves had only been modified by pharmacological means. This action can be negated only by washing out the drug used, which takes seconds, whereas the electric method takes only microseconds to have an effect.

One potential application for modifying brain waves would be in mitigating epileptic seizures. (Richardson et al., Physical Review Letters, 21 January 2005; lab website,www.neuraldynamics.org; contact Bruce Gluckman, bgluckma@gmu.edu, 703-993-4384 or Steven Schiff, sschiff@gmu.edu) Part of the George Mason contingent also was involved in the recent discovery of true spiral waves in the sensory cortex of the brain (Huang et al J Neurosci 24: 9897-9902, 2004).