Tag Archives: brain wave

eeg strap

Meet the ‘brainprint’: scientists can now identify you with 100% accuracy based on brain waves alone

There are many intimate and unique bodily characteristics that can be used to accurately identify you. These biometric include your fingerprint, DNA, retina, even your voice. All of these signals, however, can be forged which can be a serious security risk if you’re running a tight-lip operation like, say, the Pentagon. There’s one biometric that might not be forgeable: your thoughts. In a breakthrough research, a team at Binghamton University showed that it’s possible to identify a person with 100 percent accuracy based on their response to a visual stimulus like the word “conundrum” or a picture showing a slice of pizza. We each devour pizza uniquely in our minds, it seems, and that’s enough to tell who you are or aren’t.

eeg strap

Credit: Jonathan Cohen/Binghamton University

Previously, Sarah Laszlo and Zhanpeng Jin showed it was possible to identify a person out of a group of 32 people with 97 percent accuracy based on how their brains responded to words. Now, not only have they incorporated images, but also upped accuracy from only 97 to a full 100 percent. Considering the application they envision is high-level security clearance, that measly three percent makes all the difference in the world.

“When you take hundreds of these images, where every person is going to feel differently about each individual one, then you can be really accurate in identifying which person it was who looked at them just by their brain activity,” said Laszlo.

“If someone’s fingerprint is stolen, that person can’t just grow a new finger to replace the compromised fingerprint—the fingerprint for that person is compromised forever. Fingerprints are ‘non-cancellable.’ Brainprints, on the other hand, are potentially cancellable. So, in the unlikely event that attackers were actually able to steal a brainprint from an authorized user, the authorized user could then ‘reset’ their brainprint,” Laszlo said.

For the study, the researchers worked with 50 participants who wore an electroencephalogram headset which recorded brain wave responses to as many as 500 individual images.

“We tend to see the applications of this system as being more along the lines of high-security physical locations, like the Pentagon or Air Force Labs, where there aren’t that many users that are authorized to enter, and those users don’t need to constantly be authorizing the way that a consumer might need to authorize into their phone or computer,” Jin said.

But is this really unforgeable? There’s nothing that can’t be hacked, they say — it just might take a long time. Hacking someone’s brainwaves, now that’s some serious food for thought. I also have a personal dilemma. Neuroscientists seem to unanimously agree that the brain is plastic, so brain wave response to certain stimuli will change in time and with experience. Your response to pizza might differ ten years from now. In a way, as each moment passes I’m a different person, but inherently physical characteristics like fingerprints and DNA stay the same, which is why they’re so reliable as biometrics.

What do you think? Will this ever really work in real-life? Share your comments below. 

conscious-unconscious

How the brain loses and gains consciousness

conscious-unconsciousFor more than two centuries physicians have been using general anesthetics to perform surgeries, however even now in the 21st century scientists know very little about what happens to the brain when the patient moves to and fro a state of consciousness. This becomes even more important when you consider the very rare but frightening cases in which some patients wake up from anesthesia during surgery. MIT scientists have now found the process that moves the brain from conscious to unconscious and vice versa, furthering our understanding. Also, novel monitoring devices that can accurately determine whether a patient is about to wake up can be now created.

“When anesthesiologists are taking care of someone in the operating room, they can use the information in this article to make sure that someone is unconscious, and they can have a specific idea of when the person may be regaining consciousness,” says senior author Emery Brown, an MIT professor of brain and cognitive sciences and health sciences and technology and an anesthesiologist at MGH.

In the new study, MIT scientists monitored the brain activity of volunteers that were under anesthetics for two hours at a time. Each participant had an array of 64 electrodes attached to the scalp. Propofol, the most common anesthetic, was steadily injected in the participants, while the researchers monitored their response to sounds.

Every four seconds a mechanical tone or the participant’s name was played in the foreground, time at each the participant had to push a button to signal that it was received. During all this time, the EEG monitored brain activity. Once the subjects became less responsible, distinct brain patterns surfaced. Early on, when the subjects were just beginning to lose consciousness, the researchers detected an oscillation of brain activity in the low frequency (0.1 to 1 hertz) and alpha frequency (8 to 12 hertz) bands, in the frontal cortex. A specific relationship between the two frequency bands was also inferred: Alpha oscillations peaked as the low-frequency waves were at their lowest point.

Consciousness: switch on, switch off

Later on they found that while the subject become fully under anesthesia the alpha oscillations flipped so their highest points occurred when the low frequency waves were also peaking. This resulting pattern blocked neural communications between various regions of the brain. For instance, the frontal cortex and the thalamus, which normally communicate with each other across a very broad frequency band to relay sensory information and control attention, were constrained from sharing information.

This array of videos shows spectrographic data (representing brain wave frequencies) from each of 44 electrodes attached to the scalp of a healthy volunteer undergoing propofol anesthesia. The spectrograms are arranged according to their approximate position on the scalp, with the front of the head at the top of the screen, and the back of the head at the bottom of the screen. Activity moves from back to front with loss of consciousness (levels 1 to 5) and from back to front with return of consciousness (levels 6 to 8). Each video shows brain activity throughout a 140-minute period of the study. Video by Aylin Cimenser.

In a similar previous study, conducted by the same team of researchers, only with epileptic volunteers, instead of healthy ones, similar findings were made. Then, researchers found that during anesthesia, neurons within small, localized brain regions are active for a few hundred milliseconds, then shut off again for a few hundred milliseconds. It’s this flickering brain pattern that creates the low frequency oscillations that block communications between areas of the brain and pulls us into unconsciousness.

“You were not supposed to wake up”

When the anesthetic dose was lowered, the participants began to regain consciousness, and a reversal of brain activity occurred. Yet again, the alpha frequencies flipped so that they were at their peak when the low-frequency waves were at their lowest point.

“That is the signature that would allow someone to determine if a patient is coming out of anesthesia too early, with this drug,” said Patrick Purdon, an instructor of anesthesia at MGH and Harvard Medical School.

Only in one in 10,000 operations patients wake up from anesthesia, but this is enough to cause general panic surrounding surgeries. Armed with this new found knowledge, anesthesiologists might soon have monitoring tools based on brain wave patterns that accurately signal whether or not the patient is fully unconscious or not.

The researchers now plan on monitoring brain signals for other anesthesia drugs as well. The findings were reported in the journal Proceedings of the National Academy of Sciences

children-reading

Biological marker for dyslexia found. Good news: reading can be improved

children-reading

Researchers at Northwestern University claim they have uncovered the mechanisms that lead to difficulty in reading. Apparently, there is a direct correlation between one’s ability to encode speech sound in the brain and ease of reading. The scientists also devised an experiment and saw that children with reading impairment significantly improved after being fitted with a listening device.

It’s rather unfortunate that dyslexia is labeled by many with the stigma of poor intelligence. The condition has absolutely no relation to intelligence, it just turns reading into a struggle for those afflicted by it. This is a fact well worth considering, even more since one in ten children are believed to suffer from dyslexia. Similar to dyslexia, dyscalculia – a condition in which people are unable (or find it extremely difficult) to do even the simplest of arithmetical tasks – is yet another condition that is unrelated to intelligence, but still gives children a tough time and unasked for pressure.

Seeking the uncover the biological markers that underline dyslexia, the researchers recorded the automatic brain wave responses of 100 school-aged children to speech sounds. They found that the best readers encoded the sound most consistently while the poorest readers encoded it with the greatest inconsistency.

“We discovered a systematic relationship between reading ability and the consistency with which the brain encodes sounds,” says Nina Kraus, Hugh Knowles Professor of Neurobiology, Physiology and Communication. “Unstable Representation of Sound: A Biological Marker of Dyslexia,” co-authored by Jane Hornickel, will appear in the Feb. 20 issue of The Journal of Neuroscience.

Vowels are sounds that are the easiest to recognize since they’re long and simple; the real difficult sounds that can confuse the brain are consonants, which are shorter and more acoustically complex.

In prior work, Kraus and colleagues fitted children that had a difficult time reading with an auditory device that directly fed what their teacher spoke into their ears. After a while, the scientists found that showed improvement not only in reading but also in the consistency with which their brains encoded speech sounds, unsurprisingly consonants in particular.

“Use of the devices focused youngsters’ brains on the “meaningful” sounds coming from their teacher, diminishing other, extraneous distractions,” said Kraus. “After a year of use, the students had honed their auditory systems and no longer required the assistive devices to keep their reading and encoding advantage.”

The Northwestern study is the latest in a series of studies conducted by universities from around the world that have reached similar findings, namely that reading is directly linked with auditory skills, including and not limited to, the ability to rhyme sounds and to recognize rapidly occuring sounds.

“Understanding the biological mechanisms of reading puts us in a better position to both understand how normal reading works and to ameliorate it where it goes awry,” says Kraus.

“Our results suggest that good readers profit from a stable neural representation of sound, and that children with inconsistent neural responses are likely at a disadvantage when learning to read,” Kraus adds. “The good news is that response consistency can be improved with auditory training.”

parkinsons-phase-cancellation

Parkinson’s tremors significantly reduced after electrical signal cancels brain waves

Credit: John-Stuart Brittain et al./Current Biology

Credit: John-Stuart Brittain et al./Current Biology

For most Parkinson’s patients, tremors associated with this devastating disease make living a normal life extremely difficult, if not impossible. Cooking, eating, even tying one’s shoelaces, basically anything that implies limb manipulation is very difficult to achieve by one’s self. A novel type of therapy developed by physicians at Oxford University, however, brings a glimmer of hope that Parkinson’s patients might have the chance at living a normal life once again; their findings showed a 50% decrease in tremors after applying an electrical current to key motor areas of the brain.

There are a number of drugs and treatments that address Parkinson’s tremors. However most patients don’t respond properly or only show mild improvements – far from enough. The best improvements in alleviating tremors have been found using  deep brain stimulation, a technique that involves surgery to insert electrodes deep into the brain itself to deliver electrical impulses.

As you can imagine, this particular method isn’t really appealing to patients seeing how their skulls need to be open and have electrodes fitted inside the brain – not to mention the health hazards that might surface, like brain bleeding and the likes.

Oxford University researchers have reached much of the same or better results as brain stimulation using a method that does not imply surgery, by applying electrical signals with electrodes fitted on the scalp, instead of embedded inside the brain itself.

Cancelling Parkinson’s tremor causing brain waves

Credit: John-Stuart Brittain et al./Current Biology

Credit: John-Stuart Brittain et al./Current Biology

Called transcranial alternating current stimulation (TACS), the technique involves placing electrode pads on the outside of the patient’s skull, one close to the base of the neck and one on the head, above the motor cortex (part of the brain implicated in controlling the tremors).

The science behind it is simply mind-boggling. Basically, our brain operates in brain waves, so by stimulating the brain with matching waves, one can amplify that particular wave or, in the case of Parkinson’s caused tremor brain waves, cancel them out.

Thus, a small alternating current stimulation is passed through the electrodes that delivers an oscillating tremor signal at 180 out of phase to cancel it out, suppressing the physical tremor. As an analogy, some of you might be familiar with noise-canceling headphones: when you turn them on, the headphones detect ambient noise and deliver a signal that cancels it out so you basically don’t hear anything besides a faint beep. Achieving a similar effect, however, with particular brain waves is simply amazing!

The technique was tested on 15 people with Parkinson’s disease at Oxford‘s John Radcliffe Hospital, and resulted in a 50%  reduction in resting tremors among the patients.

“Tremors experienced by Parkinson’s sufferers can be devastating and any therapy that can suppress or reduce those tremors significantly improves quality of life for patients. We are very hopeful this research may, in time, lead to a therapy that is both successful and carries reduced medical risks. We have proved the principle, now we have to optimize it and adapt it so it is able to be used in patients.”

Now, the next step the researchers plan on making is to devise electrodes small, yet still potent enough to work, that can be implanted beneath the skin of patient’s skull, as well as a portable system that detects the brain signal and adjusts the delivered stimulation to cancel it out.

Findings were reported in the journal Current Biology.

 

 

Berkeley scientists crack brain wave code, hinting at mind reading device

In the not so distant future, scientists could be able to eavesdrop on a patient’s inner monologues or communicate with those who cannot speak, thanks to a breakthrough made by researchers from the University of California, Berkeley.

They have astonishingly managed to crack the ‘code’ of a brain wave by decoding electrical activity in a region of the human auditory system called the superior temporal gyrus (STG). Basically, by analyzing the STG activity they were able to reconstruct words that subjects listened in conversation by attaching electrodes to their bare brains.

During surgery, patients were played recordings of people speaking average conversations; even though they were ‘asleep’, their brains still processed the data, and as they did, the electrodes transferred the information to a computer which then calculated how the brains responded according to the speech frequencies they heard. It could therefore reproduce a sound close enough to the original word for the researchers to guess the word quite accurately. Of course, the first use they thought of was in a new type of prosthetic.

“This is huge for patients who have damage to their speech mechanisms because of a stroke or Lou Gehrig’s disease and can’t speak,” said Robert Knight, Professor of Psychology and Neuroscience at UC Berkeley. “If you could eventually reconstruct imagined conversations from brain activity, thousands of people could benefit. “

For example, people like Stephen Hawking could make themselves heard using this technology which processes their own thoughts. However, this research is focused only on people who hear actual sounds and interpret them.

“But to use this for a prosthetic device, these principles would have to apply to someone who is imagining speech,” cautioned Brian N. Pasley, leading author. “There is some evidence that perception and imagery may be pretty similar in the brain. If you can understand the relationship well enough between the brain recordings and sound, you could either synthesize the actual sound a person is thinking, or just write out the words with a type of interface device.”

However, the research was based only on 15 people and the technique is far from being viable, and there will be some serious obstacles to be crossed, not only for the researchers, but for subjects as well – it works only on patients who are undergoing neurosurgery and willing to have 256 electrodes attached to their exposed brains. Still, the benefits are huge, and just stop a moment and think about it: researchers are close to intercept people’s very thoughts – something which seemed sci-fi even 10 years ago, even for other scientists.

“I didn’t think it could possibly work, but Brian did it,” Knight said.

Via PLoS one