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.
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, firstname.lastname@example.org, 703-993-4384 or Steven Schiff,
email@example.com) 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).