Archive for the ‘Neuroscience’ Category
The hard part of connecting a gooey, thinking brain to a cold, one-ing and zero-ing computer is getting information through your thick skull—or mine, or anyone’s. The whole point of a skull, after all, is keeping a brain safely separate from [waves hands at everything].
So if that brain isn’t yours, the only way to tell what’s going on inside it is inference. People make very educated guesses based on what that brain tells a body to do—like, if the body makes some noises that you can understand (that’s speech) or moves around in a recognizable way. That’s a problem for people trying to understand how the brain works, and an even bigger problem for people who because of injury or illness can’t move or speak. Sophisticated imaging technologies like functional magnetic resonance can give you some clues. But it’d be great to have something more direct. For decades, technologists have been trying to get brains to interface with computer keyboards or robot arms, to get meat to commune with silicon.
It all started with a rejected grant proposal. Ahmad Hariri, a neuroscientist at Duke University, was interested in using so-called "task fMRI"—in which subjects perform specially designed cognitive tasks while having their brains scanned—combined with genetic testing and psychological evaluations. The goal was to identify specific biomarkers for differences in how people process thoughts and emotions that might determine whether a given subject would be more or less likely to experience depression, anxiety, or age-related cognitive decline like dementia in the future.
"The idea was to collect this data once, then collect it again and again and again and be able to track changes in an individual's brain over time to help us understand what changes over the course of their lives," Hariri told Ars. So he submitted a funding proposal outlining his plans for a longitudinal study along those lines. The proposal hypothesized that an individual's history of trauma, for instance, would map onto how their amygdala reacted to threat-related stimuli. And that would, in turn, enable the researchers to say something about the future mental well-being of the individual.
Hariri and his team designed four core, task-related measures to that end: one targeting the amygdala's threat response, one targeting the hippocampus and memory, one targeting the striatum and reward, and the fourth targeting the prefrontal cortex and executive control. He thought he was on solid scientific ground. So he was shocked when the proposal wasn't even scored by reviewers, based on skepticism regarding the reliability of fMRI to collect that kind of data.
Carrie Fisher had a psychedelic-induced encounter with a talking acorn. Grateful Dead drummer Bill Kreutzmann recalls the time he dropped too much acid and his cymbals began melting mid-set, forcing him to leave the stage. Ben Stiller admits he only dropped acid once, and had such a bad trip that he called his parents, Jerry Stiller (who died just this week) and the late Anne Meara. These are just a few of the celebrity psychedelic experiences recounted in the entertaining new documentary film, Have a Good Trip: Adventures in Psychedelics, now streaming on Netflix.
(Mild spoilers below.)
Psychedelics get their name from the Greek root words for "mind revealing," since they can alter cognition and perception. LSD (lysergic acid diethylamide) is perhaps the best known, along with its popular siblings psilocybin (the active ingredient in magic mushrooms); 3,4-methyl
Ian Burkhart, now 28, had a diving accident in 2010 that severely damaged his spinal cord, leaving him paralyzed and confined to a wheelchair, with only limited movement in his elbow and shoulders. Thanks to an implanted brain-computer-interface (BCI) developed by Battelle, he has made significant progress over the last six years in restoring small movements; he's even able to play Guitar Hero again. And now Battelle scientists have succeeded in restoring his sense of touch, according to a new paper in the journal Cell.
BCIs are a booming R&D field, with startups like Elon Musk's Neuralink looking ahead to a world where human beings will connect directly to their computers with either external devices (similar in function to an EEG) or biologically compatible implanted BCIs. Such systems require a way to record neural activity (electrode sensors), a way to transmit those signals (like a small wireless chipset), and algorithms that can translate those signals into action. BCIs are already a medical reality for patients with spinal cord injuries, like Burkhart, or those who suffer from Parkinson's or epileptic seizures. The benefits patients gain far outweigh the risks of surgical implantation.
Over the past 90 years or so, Battelle has been instrumental in developing such prominent technologies as the Xerox machine, cruise control, and CD-ROMs, along with numerous medical devices. Patrick Ganzer, lead author on the new Cell paper, is a research scientist with the organization's medical devices division, working with the NeuroLife group to develop a BCI for clinical trial. Burkhart has been working with Ganzer and NeuroLife since 2014 to restore motor function to his right arm.
There's a popular myth that divides people into "left brain" and "right brain" categories, whereby the former are analytical and logical, while the latter are creative and innovative. The reality, of course, is much more complicated than that, and a new brain-imaging study of improvisational jazz guitarists is a useful case in point. Researchers at Drexel University found that while the right hemisphere is associated with creativity in fairly inexperienced jazz musicians, experts with high mastery of improvisational skills actually rely primarily on the left hemisphere of the brain. They described their results in a recent paper in the journal NeuroImage.
Co-author David Rosen is a musician and scientist who started playing the piano at age eight before picking up the bass guitar in high school. (Rosen's band, Nakama, has just released a new EP, for those looking to explore some new musical vibes while we're all under isolation orders.) Because improvisation—defined as "the spontaneous invention of melodic solo lines or accompaniment parts"—is a defining feature of jazz, Rosen thought it would provide an excellent opportunity to explore the brain's role not just in creativity, but more broadly in musical perception and expression.
"I think there are a lot of interesting questions to ask about [musical] perception, both for people who are listening to music and people who are performing music," Rosen told Ars. "The brain is the part that makes us most human and lets us feel those emotions. It's almost not possible to quantify the altered state we get into when we're performing or listening to the music we like the most and that means the most to us as individuals. Ultimately, we're trying to ask very focused scientific questions about pieces of what it means to share in that musical experience."
For people with limited use of their limbs, speech recognition can be critical for their ability to operate a computer. But for many, the same problems that limit limb motion affect the muscles that allow speech. That had made any form of communication a challenge, as physicist Stephen Hawking famously demonstrated. Ideally, we'd like to find a way to get upstream of any physical activity and identify ways of translating nerve impulses to speech.
Brain-computer interfaces were making impressive advances even before Elon Musk decided to get involved, but the problem of brain-to-text wasn't one of its successes. We've been able to recognize speech in the brain for a decade, but the accuracy and speed of this process are quite low. Now, some researchers at the University of California, San Francisco, are suggesting that the problem might be that we weren't thinking about the challenge in terms of the big-picture process of speaking. And they have a brain-to-speech system to back them up.
Lost in translation
Speech is a complicated process, and it's not necessarily obvious where in the process it's best to start. At some point, your brain decides on the meaning it wants conveyed, although that often gets revised as the process continues. Then, word choices have to be made, although once mastered, speech doesn't require conscious thought—even some word choices, like when to use articles and which to use, can be automatic at times. Once chosen, the brain has to organize collections of muscles to actually make the appropriate sounds.
When we watch horror movies, our brains are hard at work, with lots of interconnected cross-talk between different regions to anticipate perceived threats and prepare to respond accordingly. This enhances our excitement while watching, according to scientists at the University of Turku in Finland. They mapped the neural activity of subjects in an MRI as they watched horror movies, and described their findings in a recent paper published in the journal NeuroImage,
According to co-author Matthew Hudson, now at the National College of Ireland in Dublin, the objective was to take a closer look at dynamic interactions in the brain during an intense emotional experience. Most prior studies on neural mechanisms have adopted a binary approach, in that the focus is on comparing two conditions. But this ignores the temporal dynamics between the two conditions—the continuous fear response.
Hudson told Ars, "We wanted to use a naturalistic stimuli and new ways to analyze neural data to try and understand exactly how the fear response changes over time" rather than simply comparing brain activity before and after a perceived threat. Horror movies provided the perfect fear-inducing stimulus.