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Green arrow points to the implant in the hippocampus of a mouse brain. (Credit: Christopher Proctor)

Researchers have successfully demonstrated how an electronic device implanted directly into the brain can detect, stop, and even prevent epileptic seizures. The work represents an advance in the development of soft, flexible electronics that interface well with human tissue.

Researchers implanted the device into the brains of mice, and when the first signals of a seizure were detected, delivered a native brain chemical which stopped the seizure from progressing. The results, could also be applied to other conditions including brain tumors and Parkinson’s disease.

The researchers used a neurotransmitter that acts as the ‘brake’ at the source of the seizure, essentially signaling to the neurons to stop firing and end the seizure. The drug is delivered to the affected region of the brain by a neural probe incorporating a tiny ion pump and electrodes to monitor neural activity.

When the neural signal of a seizure is detected by the electrodes, the ion pump is activated, creating an electric field that moves the drug across an ion exchange membrane and out of the device, a process known as electrophoresis. The amount of drug can be controlled by tuning the strength of the electric field.

The researchers found that seizures could be prevented with relatively small doses of drug representing less than 1 percent of the total amount of drug loaded into the device. This means the device should be able to operate for extended periods without needing to be refilled. They also found evidence that the delivered drug, which was in fact a neurotransmitter that is native to the body, was taken up by natural processes in the brain within minutes which, the researchers say, should help reduce side effects from the treatment.

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