Bright-field image showing the mesh electronics being injected through sub-100 micrometer inner diameter glass needle into aqueous solution. Image Credit: Lieber Research Group, Harvard University
The ability to manipulate objects on a very small scale through nanotechnology has opened the door to new ways of monitoring what’s going on with our bodies. The brain is no exception, and now researchers have created microscopic, flexible electronics that can be implanted into parts of the brain using nothing but a small needle. These electronic probes could vastly change how we monitor brain activity and treat ailments.
The new electronics, reported this week in Nature Nanotechnology, come from Charles Lieber and his colleagues. Lieber, a professor of chemistry at Harvard’s School of Engineering and Applied Sciences, says many existing microscopic electronic devices come in the form of chips built to work on a flat surface. “That’s not really enough when you’re looking at most biological systems because they’re 3D,” he says. “Even if the surface can be bent, it’s still more or less a two-dimensional structure.”
While doctors can already surgically implant electronics into the brain, such as in cases of Parkinson’s Disease where deep brain stimulation is used to treat tremors, many of these devices are quite large. Implanting them is an invasive surgical procedure, and they cause an immune response from the body, which sees the devices as foreign.
Leiber wanted to create an electronic device small enough and flexible enough to be implanted inside the body swiftly and silently, without eliciting a negative response. For inspiration, he looked to bioscaffolds, lab-grown 3D materials often implanted in damaged tissue to serve as a sort of support structure for the development of new, healthy tissue. Scaffolds are used in procedures like bone and cartilage regeneration. Lieber set out to create a microscopic bioscaffold made from electronics.
The result is a tiny mesh of electrodes that be can be implanted in living tissue by a tiny needle just 0.1 mm in diameter. The mesh is incredibly thin and up to a million times more pliable than existing flexible electronic probes. “The flexibility is really approaching that of the tissue,” Lieber says, “so it starts to look structurally like a neural network and have mechanical property of dense neural tissue.”
The team rolled up the electronics within a needle and then injected them into the hippocampuses of lab mice, where they unfolded to their original shape within an hour without sustaining any damage. They then were able to monitor, live, the neural activity of the mice. Five weeks later, the mice's immune systems showed no response to the foreign objects.
Lieber also implanted the flexible electronics into mice brain ventricles—the fluid-filled spaces—and was surprised to see the neurons attach themselves to the mesh and multiply. “These neurons were migrating onto our mesh electronic scaffold,” he says. “They were very happy and starting to proliferate.”
How might these tiny electric probes be used in the future? They could help improve procedures in stroke patients where stem cells are implanted in the brain to repair damaged tissue. “The cells do need some support to develop well,” Lieber says. His electronics could provide that initial support and then monitor the progress. Or, imagine if you could skip invasive heart surgery and instead just implant electronics with the prick of a needle.
Lieber says a lot more research is needed to understand all the potential applications. “I think a good sign of a research area is there are a lot more questions that you can get excited about than you have the time or resources to answer,” he says. “Can we wire things up the way biology does? If we can do that then we are going to be able to measure things that we couldn’t before and improve therapeutic care in a dramatic fashion.”
GIFs are silent—otherwise they wouldn't be GIFs. But some people claim to hear distinct noises accompanying certain clips. Check out the GIF below as an example: Do you hear a boom every time the structure hits the ground? If so, you may belong to the 20 to 30 percent of people who experience "visual-evoked auditory response," also known as vEAR.
Researchers from City University London recently published a paper online on the phenomenon in the journal Cortex, the British Psychological Society's Research Digest reports. For their study, they recruited more than 4000 volunteers and 126 paid participants and showed them 24 five-second video clips. Each clip lacked audio, but when asked how they rated the auditory sensation for each video on a scale of 0 to 5, 20 percent of the paid participants rated at least half the videos a 3 or more. The percentage was even higher for the volunteer group.
The likelihood of visual-evoked auditory response, according to the researchers, directly relates to what the subject is looking at. "Some people hear what they see: Car indicator lights, flashing neon shop signs, and people's movements as they walk may all trigger an auditory sensation," they write in the study.
Images packed with meaning, like two cars colliding, are more likely to trigger the auditory illusion. But even more abstract images can produce the effect if they have high levels of something called "motion energy." Motion energy is what you see in the video above when the structure bounces and the camera shakes. It's why a video of a race car driving straight down a road might have less of an auditory impact than a clip of a flickering abstract pattern.
The researchers categorize vEAR as a type of synesthesia, a brain condition in which people's senses are combined. Those with synesthesia might "see" patterns when music plays or "taste" certain colors. Most synesthesia is rare, affecting just 4 percent of the population, but this new study suggests that "hearing motion synesthesia" is much more prevalent.
In medicine, magnetic resonance imaging (MRI) uses powerful magnetic fields and radio waves to show what's happening inside the body, producing dynamic images of our internal organs. Using similar technology that tracks blood flow, functional magnetic resonance imaging (fMRI) scans can show neuroscientists neural activity, indicating what parts of the brain light up when, for instance, a person thinks of an upsetting memory or starts craving cocaine. Both require staying within a massive MRI machine for the length of the scan.
There's some controversy over how scientists interpret fMRI data in particular—fMRI studies are based on the idea that an increase of blood flow to a region of the brain means more cellular activity there, but that might not be a completely accurate measure, and a 2016 report found that fMRI studies may have stunning rates of false positives.
But we're not here to talk about results. We're here to talk about all the weird, weird things scientists have asked people to do in MRI machines so that they could look at their brains and bodies. From getting naked to going to the bathroom, people have been willing to do some unexpected activities in the name of science. Here are just a few of the oddest things that people have done in scanners at the behest of curious researchers.
1. SING OPERA
Researchers once invited world-famous opera singer Michael Volle to sing inside an MRI at the University of Freiburg in Germany. The baritone sang a piece from Richard Wagner's opera Tannhäuser as part of a 2016 study on how the vocal tract moves during singing at different pitches and while changing volume. The study asked 11 other professional singers with different voice types to participate as well. They found that the larynx rose with a singer's pitch, but got lower as the song got louder, and that certain factors, like how open their lips were, correlated more with how loud the singer was than how high they were singing. The scientists concluded that future research on the larynx and the physical aspects of singing should take loudness into consideration.
That study wasn't the first to take MRI images of singers. In 2015, researchers at the University of Illinois demonstrated their technique for recording dynamic MRI imaging of speech using video of U of I speech specialist Aaron Johnson singing "If I Only Had a Brain" from The Wizard of Oz.
2. REACT TO ROBOT-DINOSAUR ABUSE
Stills from the videos participants watched of robot dinosaurs being treated kindly or unkindly.
To test whether or not humans can feel empathy with robots for a 2013 study, researchers put participants into an fMRI machine and made them watch videos of humans and robotic dinosaurs. The videos either included footage of the human or robot being stroked or tickled, or the subject being beaten and choked. The brain scans showed similar activity for people viewing both videos, suggesting that people might be able to feel similar empathy for robots as for people.
To see whether the brain responds to emotional pain in similar ways to physical pain, researchers asked participants in a 2003 study to experience social rejection within an fMRI machine. During the scans, participants played a virtual ball-tossing game against two other players—whom they believed to be other study participants in other scanners—by watching a screen through goggles and pressing one of two keys to toss the ball to one of the other players. They were actually playing against a computer that was programmed to eventually exclude the human player. At some point during the game, the computer-controlled players stopped throwing the human player the ball, causing them to feel excluded and ignored. The researchers found that the excluded study subjects showed brain activation in regions similar to the ones seen in studies of physical pain.
Watching people poop through MRI imaging is a surprisingly common medical technique. It's called magnetic resonance defecography. Doctors use it to diagnose issues with rectal function, analyzing how the muscles of the pelvis are working and the cause of bowel issues. The scan involves having ultrasound jelly and a catheter inserted into your butt, donning a diaper, and crawling inside an MRI scanner. Then, on command, you clench your pelvic muscles in various ways as ordered by the doctor, eventually resulting in pooping out the ultrasound jelly and whatever else you might need to evacuate. No pressure.
5. HAVE SEX …
MRI images of a woman at rest, in a pre-orgasmic phase, and 20 minutes after orgasm (L–R)
Schultz et al. in BMJ, 1999
Scientists have also recorded MRI body scans of couples having sex. In the late '90s, Dutch researcher Pek Van Andel and his colleagues at the University Hospital Groningen asked eight couples to come into their lab on a Saturday and have sex in the tube of an MRI scanner in order to analyze how genitals fit together during heterosexual intercourse. Despite the surroundings, they apparently had a fine time. "The subjective level of sexual arousal of the participants, men and women, during the experiment was described afterwards as average," the study noted.
Meanwhile, other researchers are trying to capture scientific images of sex in different, sometimes even more awkward ways. For her 2008 bookBonk: The Curious Coupling Of Sex And Science, science writer Mary Roach and her husband had sex in a lab at University College London while a researcher stood next to them and held an ultrasound wand to her abdomen.
Scientists still don't know all that much about how orgasms work, so various studies have asked participants to come into the lab, lay down in an fMRI scanner, and stimulate themselves to orgasm. (A reporter at Inside Jersey went to Rutgers to take part in the university's orgasm research herself in 2010. She brought her own sex toy, but the lab was kind enough to provide the lube.)
Over the course of their work, Rutgers researchers have found that when people bring themselves to orgasm within an fMRI machine, it activates more than 30 brain systems, including ones that you wouldn't think would be involved in getting off, like the prefrontal cortex, which is associated with problem solving and judgment.
Singers aren't the only music professionals to get inside an fMRI machine for science. For a study published in 2015, 17 young composers were asked to create a piece of music while Chinese researchers examined their brain activity. While all of them played the piano, they were asked to compose a piece for an instrument none of them know how to play—the zheng, a traditional Chinese string instrument. They were given a musical staff with just a few introductory notes already written as inspiration and asked to come up with something from there. As soon as they exited the scanner, they wrote down the notes they had imagined during the imaging process. The researchers found that the composers' visual and motor cortex showed less activity than usual, the opposite of what researchers have seen in studies of musical improvisation.
8. HAVE AN OUT-OF-BODY EXPERIENCE
Activated portions of the brain during an out-of-body experience
In a 2014 study, psychologists at the University of Ottawa recruited an undergraduate student who reported that she could have out-of-body experiences at will to do so within the confines of an fMRI scanner.
"She was able to see herself rotating in the air above her body, lying flat, and rolling along with the horizontal plane," the researchers wrote. "She reported sometimes watching herself move from above but remained aware of her unmoving 'real' body."
She entered the scanner six times, reporting out-of-body experiences that included feeling as if she were above her body and spinning or rocking side-to-side. The researchers found that the experience activated regions of her brain associated with kinesthetic imagery, the feeling of visualizing movement (as athletes often do during training and competitions, for instance), and a deactivated the visual cortex.