Detecting and controlling seizures with brain implants
By Ben Coxworth
June 3, 2011
In the future, people who are prone to seizures may get an array of electrodes implanted in their brains. These electrodes would be capable of detecting the onset of a seizure, and then releasing medication to prevent it from happening. While it might sound far-fetched, scientists at the University of Pittsburgh have already demonstrated the technology on lab rats.
Multielectrode arrays (MEAs) are capable of recording or controlling the electrical activity in neurons, and are used in devices such as ear implants and pacemakers. The Pittsburgh team coated MEAs with the polymer Polypyrrole (PPy), which is known for its electrical conductivity. Mixed in with the PPy were anti-convulsive neurochemicals.
The coated MEAs were then placed on a rat's brain, and electrically stimulated. This caused the neurochemicals to dissociate from the PPy, and diffuse into the adjacent regions of the brain. Testing indicated that after dissociation, the drugs still remained effective.
Similar technologies have involved implants with built-in drug reservoirs, although these would be larger than the coated MEAs, and could cause tissue damage.
"By directly loading a drug of interest onto an individual electrode site and using an electrical signal to trigger its release, we can precisely control the drug delivery site with ease," said the study's co-author, Prof. X Tracy Cui. "Additionally, our technology can be used for a combination of exogenous chemicals such as subtype-specific receptor antagonists, thus potentially allowing for more precise dissection of neural circuit function at the molecular level."
The research was published this week in the Journal of Neural Engineering.