A Tiny Electric Brain Implant Could Wake People in Comas
Unconscious monkeys zapped in one area of the brain suddenly woke up
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Last year, a woman from the United Arab Emirates woke up in a German hospital after a road accident in 1991 left her in a coma for 27 years. Her doctors couldn’t believe it.
Her case was exceedingly rare. Only a handful of other patients have ever recovered after that long. Some people may gradually come out of a coma or wake up after a few weeks. Some become what’s known as “minimally conscious,” showing occasional awareness and responsiveness. Others may enter a vegetative state — where they seem awake but show no signs of awareness. These patients may eventually regain a degree of awareness, but they could also remain in a vegetative state for years.
To help these people, scientists have been trying to pinpoint where consciousness resides in the human brain. Doing so would not only solve one of the central questions of neuroscience, but it could also lead to treatments to “awaken” people in comas.
Brain scans have suggested that an area called the thalamus, which is located just above the brain stem, plays a role in consciousness. In a paper published in the journal Neuron on Wednesday, researchers at the University of Wisconsin-Madison identified a tiny zone within this region — just a few millimeters in size — that, when stimulated appropriately, appears to wake unconscious monkeys. It may be especially important in keeping humans awake and conscious as well.
First, the researchers inserted electrodes in the brains of macaques, recording activity from multiple brain areas at a time. By studying animals when they were awake, sleeping, or anesthetized, they narrowed down the region that seemed to be involved in consciousness to an area within the thalamus, only 1–1.5 millimeters across and 3–4 millimeters deep, called the central lateral thalamus.
Then, they used an approach called deep brain stimulation on anesthetized monkeys to deliver electrical pulses to this region. Deep brain stimulation, which involves surgically inserting electrodes into the brain to administer intermittent electric stimulation, is an approved treatment for Parkinson’s disease and a handful of other conditions…
