Feel like your brain is getting a little sluggish? In the future you may be able to go in for a brain tweak using ultrasound.
Surprising Tests Show Ultrasound Could Slow Brain’s Aging
Physical therapists already use ultrasound to help some injuries heal faster. One day those treatments could be used to keep older brains sharp, even as the years go by. An accidental discovery in the lab by Australian researchers opened the door for this approach to become a reality.
It started when a team from the Queensland Brain Institute was doing a safety study for a noninvasive scanning ultrasound treatment they had developed to reverse Alzheimer’s in mice. That alone made headlines when it came out last year. But they wanted to go a step farther and make sure that their technique wouldn’t damage healthy brain cells, lead researcher Robert Hatch explained to the Australian Broadcasting Corporation.
Over the course of six weeks, Hatch and his colleagues treated mice in the lab with either one or six scanning ultrasound sessions. They reviewed the mice’s brain cell structure and function two hours, one day, one week and then three months after the animals received the ultrasound treatment, according to the lab.
What they found was unexpected. Normally aging reduces the structure of impulse-conducting cells in the hippocampus, the section of our brains heavily involved in memory and learning. Much to the researchers’ surprise, the treatments appeared to slow down the brain aging process for the mice. Instead of getting smaller, the brain cell structures stayed the same.
Ultrasound May Boost Brain Performance
Ultrasound may improve sensory perception, according to a new in humans.
By directing ultrasound to a specific brain area, researchers were able to improve people’s ability to discriminate between sensory inputs. Ultrasound is sound far above the upper limit of what humans can hear. It’s useful in medical imaging. and technicians send bursts of ultrasound through tissue and record the echoes, creating a picture of what’s inside — whether it’s an injured knee or a fetus in utero.
Ultrasound also has potential for mapping the connectivity of the brain. Neuroscientists are particularly interested in understanding how brain areas chat with one another; in fact, a new federal project, the BRAIN Initiative, has the goal of mapping the healthy human brain.
Tyler and his colleagues focused on sensory perception from the hand. They first placed an electrode on the wrist, over the nerve that carries impulses from the hand to the brain. Using a small current, they stimulated that nerve while focusing ultrasound on the brain region that processes the nerve’s signals.
The researchers recorded the participants’ brain responses with electroencephalography (EEG), electrodes on the scalp that measure the electrical activity of the brain. The ultrasound weakened the brain waves that encode the tactile stimulation, they found.
But the next set of experiments revealed something truly strange.
The researchers conducted two tests of sensory perception. In the first, participants feel two pins against their skin and must distinguish whether they are being touched at one or two points. The closer the pins are to each other, the harder the task. In the second, researchers blow a series of air puffs against the participants’ skin, and they must determine how many individual puffs they feel. The faster the puffs, the harder they are to discriminate.
Instead of these weak brain signals translating to poorer sensory perception, people’s performance actually improved on both tests.
“Our observations surprised us,” Tyler said. “Even though the brain waves associated with the tactile stimulation had weakened, people actually got better at detecting differences in sensations.”
Tweaking the brain
What might explain this seeming paradox? The answer might have to do with how neurons function. When brain cells communicate, they can urge their neighbors to become active (excitation) or tell everyone to quiet down (inhibition). The ultrasound may have affected the brain region’s balance of excitation and inhibition, Tyler said.
As a result, the excitation impulses may not have spread so far, essentially giving the brain a better triangulation of where the sensory inputs were coming from.
The boost in sensory perception vanished when researchers moved the ultrasound’s focus just a half inch (1 centimeter). That means the method is a fine-grained way to “tweak” brain circuits, both to map their activity and potentially to treat brain disorders.
“In neuroscience, it’s easy to disrupt things,” said Tyler. “We can distract you, make you feel numb, trick you with optical illusions. It’s easy to make things worse, but it’s hard to make them better. These findings make us believe we’re on the right path.”