Consciousness on-off switch found deep in the brain
For the first time, researchers discover how to shut down consciousness … and then fire it back up.
Tue, Jul 08, 2014 at 12:23 PM
Consciousness – the state of being aware of all that is around you – is one of the most profound mysteries of the brain. Most neuroscientists agree that it works as an organizing mechanism that directs all of our sensory information into a coherent experience rather than just of a bunch of random perceptions. A conductor, of sorts, that for example might take the smell and sight of a cake, the sound of its name and the memory of its flavor and tie it together as a single conscious experience of being presented with a slice of cake.
Our experience of consciousness generally involve being awake, or conscious, and being asleep, when our consciousness it turned off.
For more than a century scientists have been trying to find the secret button to manipulate consciousness by zapping certain parts of the brain with electricity to turn them off, but they have been unable to make someone lose consciousness this way.
However, that’s exactly what happened in Washington, D.C., when neurologist Mohamad Koubeissi at the George Washington University and his colleagues – somewhat by accident – found the golden spot. He and his team were conducting trials on low-frequency deep-brain stimulation to reduce epileptic seizures in patients. They found they could reduce epileptic seizures in patients by 92 percent without impairing memory, which was pretty remarkable enough on its own.
But when they began experimenting with high-frequency electrical impulses, they came across something else entirely. When stimulating a 54-year-old female patient’s claustrum (an area of neurons at the lower part of the central brain) the woman stopped reading and stared dazedly into space. “She didn't respond to auditory or visual commands and her breathing slowed. As soon as the stimulation stopped, she immediately regained consciousness with no memory of the event. The same thing happened every time the area was stimulated during two days of experiments,” New Scientist explains in a story about the discovery.
The team successfully conducted more experiments to confirm that she was losing consciousness, not just losing the ability to speak or move. They also ensured that the phenomenon wasn’t the effect of a seizure.
Koubeissi says he believes that the claustrum plays a crucial role in igniting conscious experience. "I would liken it to a car," he says. "A car on the road has many parts that facilitate its movement – the gas, the transmission, the engine – but there's only one spot where you turn the key and it all switches on and works together. So while consciousness is a complicated process created via many structures and networks, we may have found the key."
And while at this point it’s just a single-case study, the “key” may be used in the future to help open the door for people who are trapped in minimal consciousness, like comas.
"Perhaps we could try to stimulate this region in an attempt to push them out of this state," added Koubeissi.
Related on MNN: