A man paralyzed from the neck down due to a spinal cord injury he sustained in 2007 has shown he can communicate his thoughts, thanks to a brain implant system that translates his imagined handwriting into actual text.

The device – part of a longstanding research collaboration called BrainGate – is a brain-computer interface (BCI), that uses artificial intelligence (AI) to interpret signals of neural activity generated during handwriting.

In this case, the man – called T5 in the study, and who was 65 years of age at the time of the research – wasn’t doing any actual writing, as his hand, along with all his limbs, had been paralyzed for several years.

But during the experiment, reported in Nature earlier in the year, the man concentrated as if he were writing – effectively, thinking about making the letters with an imaginary pen and paper.

As he did this, electrodes implanted in his motor cortex recorded signals of his brain activity, which were then interpreted by algorithms running on an external computer, decoding T5’s imaginary pen trajectories, which mentally traced the 26 letters of the alphabet and some basic punctuation marks.

“This new system uses both the rich neural activity recorded by intracortical electrodes and the power of language models that, when applied to the neurally decoded letters, can create rapid and accurate text,” says first author of the study Frank Willett, a neural prosthetics researcher from Stanford University.

Similar systems developed as part of the BrainGate have been transcribing neural activity into text for several years, but many previous interfaces have focused on different cerebral metaphors for denoting which characters to write – such as point-and-click typing with a computer cursor controlled by the mind.

It wasn’t known, however, how well the neural representations of handwriting – a more rapid and dexterous motor skill – might be retained in the brain, nor how well they might be leveraged to communicate with a brain-computer interface, or BCI.

Here, T5 showed just how much promise a virtual handwriting system could offer for people who have lost virtually all independent physical movement.

A diagram of how the system works. (F. Willett et al., Nature, 2021, Erika Woodrum)

In tests, the man was able to achieve writing speeds of 90 characters per minute (about 18 words per minute), with approximately 94 percent accuracy (and up to 99 percent accuracy with autocorrect enabled).

Not only is that rate significantly faster than previous BCI experiments (using things like virtual keyboards), but it’s almost on par with the typing speed of smartphone users in the man’s age group – which is about 115 characters or 23 words per minute, the researchers say.

“We’ve learned that the brain retains its ability to prescribe fine movements a full decade after the body has lost its ability to execute those movements,” Willett says.

“And we’ve learned that complicated intended motions involving changing speeds and curved trajectories, like handwriting, can be interpreted more easily and more rapidly by the artificial-intelligence algorithms we’re using than can simpler intended motions like moving a cursor in a straight path at a steady speed.”

Basically, the researchers say that alphabetical letters are very different from one another in shape, so the AI can decode the user’s intention more rapidly as the characters are drawn, compared to other BCI systems that don’t make use of dozens of different inputs in the same way.

The man’s imagined handwriting, as interpreted by the system. (Frank Willett)

Despite the potential of this first-of-its-kind technology, the researchers emphasize that the current system is only a proof of concept so far, having only been shown to work with one participant, so it’s definitely not a complete, clinically viable product as yet.

The next steps in the research could include training other people to use the interface, expanding the character set to include more symbols (such as capital letters), refining the sensitivity of the system, and adding more sophisticated editing tools for the user.

There’s plenty of work to still be done, but we could be looking at an exciting new development here, giving the ability to communicate back to people who lost it.

“Our results open a new approach for BCIs and demonstrate the feasibility of accurately decoding rapid, dexterous movements years after paralysis,” the researchers write.

“We believe that the future of intracortical BCIs is bright.”

The findings are reported in Nature.

The most recent gravitational wave observing run has netted the biggest haul yet.

In less than five months, from November 2019 to March 2020, the LIGO-Virgo interferometers recorded a massive 35 gravitational wave events. On average, that’s almost 1.7 gravitational wave events every week for the duration of the run.

This represents a significant increase from the 1.5-event weekly average detected on the previous run, and a result that has plumped up the number of total events to 90 since that first history-making gravitational wave detection in September 2015.

“These discoveries represent a tenfold increase in the number of gravitational waves detected by LIGO and Virgo since they started observing,” said astrophysicist Susan Scott of the Australian National University in Australia.

“We’ve detected 35 events. That’s massive! In contrast, we made three detections in our first observing run, which lasted four months in 2015-16. This really is a new era for gravitational wave detections and the growing population of discoveries is revealing so much information about the life and death of stars throughout the Universe.”

Of the 35 new detections, 32 are most likely the result of mergers between pairs of black holes. This is when pairs of black holes on a close orbit are drawn in by mutual gravity, eventually colliding to form one single, more massive black hole.

That collision sends ripples through space-time, like the ripples generated when you throw a rock in a pond; astronomers can analyze those ripples to determine the properties of the black holes.

An infographic showing the masses of all black hole mergers announced to date. (LIGO-Virgo/Aaron Geller/Northwestern University)

The data revealed a range of black hole masses, with the most massive clocking in at around 87 times the mass of the Sun. That black hole merged with a companion 61 times the mass of the Sun, resulting in a single black hole 141 times the mass of the Sun. That event is named GW200220_061928.

Another merger produced a black hole 104 times the mass of the Sun; both of these are considered intermediate mass black holes, a mass range between 100 and around a million solar masses, in which very few black holes have been detected.

GW200220_061928 is also interesting, because at least one of the black holes involved in the merger falls into what we call the upper mass gap. According to our models, black holes over about 65 solar masses can’t form from a single star, as stellar mass black holes do.

That’s because the precursor stars are so massive that their supernovae – known as pair-instability supernovae – ought to completely obliterate the stellar core, leaving nothing behind to gravitationally collapse into a black hole.

This suggests that the 87 solar mass black hole might be the product of a previous merger. GW200220_061928 isn’t the first that’s involved a black hole in the upper mass gap, but its detection does suggest that hierarchical black hole mergers are not uncommon.

And another event includes an object in the lower mass gap – a gap of black holes between 2.5 and 5 times the mass of the Sun. We’ve not conclusively found a neutron star larger than the former, or a black hole smaller than the latter; the event named GW200210_092254 involved an object clocking in at 2.8 solar masses. Astronomers have concluded that it’s probably a very small black hole.

“Looking at the masses and spins of the black holes in these binary systems indicates how these systems got together in the first place,” Scott said.

“It also raises some really fascinating questions. For example, did the system originally form with two stars that went through their life cycles together and eventually became black holes? Or were the two black holes thrust together in a very dense dynamical environment such as at the centre of a galaxy?”

The other three events out of the 35 involved a black hole and something else much less massive, likely a neutron star. These events are of great interest to astronomers, since they might reveal the stuff that’s inside a neutron star – if we ever detect one that emits light. By finding more of these mergers, we can start to build a better understanding of how they actually occur.

“Only now are we starting to appreciate the wonderful diversity of black holes and neutron stars,” said astronomer Christopher Berry of the University of Glasgow in the UK

“Our latest results prove that they come in many sizes and combinations – we have solved some long-standing mysteries, but uncovered some new puzzles too. Using these observations, we are closer to unlocking the mysteries of how stars, the building blocks of our Universe, evolve.”

The team’s paper has been submitted for publication, and can be found on preprint server arXiv.