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Three paralyzed men are walking again thanks to targeted neurotechnology

Spinal implants deliver intermittent bursts to stimulate movement.

Photo credit: DANIEL GARCIA/Getty Images
  • Three paralyzed men are walking in Switzerland thanks to modified spinal implants.
  • The implants provided intermittent as opposed to continuous stimulation.
  • This isn't a cure for paralysis, but the work appears to indicate a promising future.

Three paralyzed men are walking again in Switzerland with the help of a team at the École Polytechnique Fédérale de Lausanne. The innovative rehabilitation process the trio went through is now being studied to mimic its results for others in similar circumstances.

In terms of the treatment, the men first walked on a treadmill while being supported by a gurney-like device as they received jolts from sensors that were placed on their legs and feet. They then left the treadmill and walked across the ground while still receiving electric stimulation. A few months later, they were able to regain their ability to walk without the assistance of any sort of electrical stimulation whatsoever.

It's worth breaking down some of the details that went into each stage of the process: on the treadmill, for instance, participants adjusted the elevation of their step, the speed of their stride, and were asked to see if they could stop moving their legs even though they were receiving electrical stimulation. They then walked on the treadmill for an hour. They then did this activity for three months, participating in rehab 4–5 times per week. After this time, they were then able to walk hands-free without the 'hip assist' provided by the gurney-like device.

One of the curiosities that occurred during this process was the discovery that intermittent stimulation works. Continuous electric stimulation of the spinal cord, on the other hand, enabled rats to walk again, but it didn't have the same results in humans. Indeed, when it was used on the participants, they reported a loss of sensory awareness as to where their limbs even were. This appears to be explained by the fact that areas of the body that contain a single motor neuron seem to respond more effectively to low-grade stimulation than a continuous loop.

The results described here don't represent a blanket cure for paralysis. It's worth noting, for instance, that each stimulation of the spine was personalized to the three participants. The scientists at Lausanne created "an atlas of motor neuron activation maps" using a combination of MRI scans and CT scans.

But that doesn't make the results here any less impressive, noteworthy, or inspiring. As reported by the BBC, one of the doctors noted one of the patient's determination to succeed —

"I came with my daughter, Charlotte, who was one month old at the time. As we approached David, he looked her in the eye and said, 'I will walk before you'.

"When Charlotte took her first step she was 14 months old, by which time David was walking by Lake Geneva.

"He said to her, 'I have beaten you.'"

The study, which was published in Nature, can be read in full here.

Image source: Nature

Neom, Saudi Arabia's $500 billion megacity, reaches its next phase

Construction of the $500 billion dollar tech city-state of the future is moving ahead.

Credit: Neom
Technology & Innovation
  • The futuristic megacity Neom is being built in Saudi Arabia.
  • The city will be fully automated, leading in health, education and quality of life.
  • It will feature an artificial moon, cloud seeding, robotic gladiators and flying taxis.
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Tuberculosis vaccine shows promise in reducing COVID deaths

A new study suggests that a century-old vaccine may reduce the severity of coronavirus cases.

Closeup of a BCG vaccination.

Credit: Kekyalyaynen.
Surprising Science
  • A new study finds a country's tuberculosis BCG vaccination is linked to its COVID-19 mortality rate.
  • More BCG vaccinations is connected to fewer severe coronavirus cases.
  • The study is preliminary and more research is needed to support the findings.
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Human brains remember certain words more easily than others

A study of the manner in which memory works turns up a surprising thing.

Image Point Fr / Shutterstock
Mind & Brain
  • Researchers have found that some basic words appear to be more memorable than others.
  • Some faces are also easier to commit to memory.
  • Scientists suggest that these words serve as semantic bridges when the brain is searching for a memory.

Cognitive psychologist Weizhen Xie (Zane) of the NIH's National Institute of Neurological Disorders and Stroke (NINDS) works with people who have intractable epilepsy, a form of the disorder that can't be controlled with medications. During research into the brain activity of patients, he and his colleagues discovered something odd about human memory: It appears that certain basic words are consistently more memorable than other basic words.

The research is published in Nature Human Behaviour.

An odd find

Image source: Tsekhmister/Shutterstock

Xie's team was re-analyzing memory tests of 30 epilepsy patients undertaken by Kareem Zaghloul of NINDS.

"Our goal is to find and eliminate the source of these harmful and debilitating seizures," Zaghloul said. "The monitoring period also provides a rare opportunity to record the neural activity that controls other parts of our lives. With the help of these patient volunteers we have been able to uncover some of the blueprints behind our memories."

Specifically, the participants were shown word pairs, such as "hand" and "apple." To better understand how the brain might remember such pairings, after a brief interval, participants were supplied one of the two words and asked to recall the other. Of the 300 words used in the tests, five of them proved to be five times more likely to be recalled: pig, tank, doll, pond, and door.

The scientists were perplexed that these words were so much more memorable than words like "cat," "street," "stair," "couch," and "cloud."

Intrigued, the researchers looked at a second data source from a word test taken by 2,623 healthy individuals via Amazon's Mechanical Turk and found essentially the same thing.

"We saw that some things — in this case, words — may be inherently easier for our brains to recall than others," Zaghloul said. That the Mechanical Turk results were so similar may "provide the strongest evidence to date that what we discovered about how the brain controls memory in this set of patients may also be true for people outside of the study."

Why understanding memory matters

person holding missing piece from human head puzzle

Image source: Orawan Pattarawimonchai/Shutterstock

"Our memories play a fundamental role in who we are and how our brains work," Xie said. "However, one of the biggest challenges of studying memory is that people often remember the same things in different ways, making it difficult for researchers to compare people's performances on memory tests." He added that the search for some kind of unified theory of memory has been going on for over a century.

If a comprehensive understanding of the way memory works can be developed, the researchers say that "we can predict what people should remember in advance and understand how our brains do this, then we might be able to develop better ways to evaluate someone's overall brain health."

Party chat

Image source: joob_in/Shutterstock

Xie's interest in this was piqued during a conversation with Wilma Bainbridge of University of Chicago at a Christmas party a couple of years ago. Bainbridge was, at the time, wrapping up a study of 1,000 volunteers that suggested certain faces are universally more memorable than others.

Bainbridge recalls, "Our exciting finding is that there are some images of people or places that are inherently memorable for all people, even though we have each seen different things in our lives. And if image memorability is so powerful, this means we can know in advance what people are likely to remember or forget."

spinning 3D model of a brain

Temporal lobes

Image source: Anatomography/Wikimedia

At first, the scientists suspected that the memorable words and faces were simply recalled more frequently and were thus easier to recall. They envisioned them as being akin to "highly trafficked spots connected to smaller spots representing the less memorable words." They developed a modeling program based on word frequencies found in books, new articles, and Wikipedia pages. Unfortunately, the model was unable to predict or duplicate the results they saw in their clinical experiments.

Eventually, the researchers came to suspect that the memorability of certain words was linked to the frequency with which the brain used them as semantic links between other memories, making them often-visited hubs in individuals's memory networks, and therefore places the brain jumped to early and often when retrieving memories. This idea was supported by observed activity in participants' anterior temporal lobe, a language center.

In epilepsy patients, these words were so frequently recalled that subjects often shouted them out even when they were incorrect responses to word-pair inquiries.

Seek, find

Modern search engines no longer simply look for raw words when resolving an inquiry: They also look for semantic — contextual and meaning — connections so that the results they present may better anticipate what it is you're looking for. Xie suggests something similar may be happening in the brain: "You know when you type words into a search engine, and it shows you a list of highly relevant guesses? It feels like the search engine is reading your mind. Well, our results suggest that the brains of the subjects in this study did something similar when they tried to recall a paired word, and we think that this may happen when we remember many of our past experiences."

He also notes that it may one day be possible to leverage individuals' apparently wired-in knowledge of their language as a fixed point against which to assess the health of their memory and brain.

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