Computer can read letters directly from the brain

By analysing MRI images of the brain with an elegant mathematical model, it is possible to reconstruct thoughts more accurately than ever before. In this way, researchers from Radboud University Nijmegen have succeeded in determining which letter a test subject was looking at. The journal Neuroimage has accepted the article, which will be published soon. A preliminary version of the article can be read online.

Functional MRI scanners have been used in cognition research primarily to determine which brain areas are active while test subjects perform a specific task. The question is simple: is a particular brain region on or off? A research group at the Donders Institute for Brain, Cognition and Behaviour at Radboud University has gone a step further: they have used data from the scanner to determine what a test subject is looking at. The researchers ‘taught’ a model how small volumes of 2x2x2 mm from the brain scans - known as voxels - respond to individual pixels. By combining all the information about the pixels from the voxels, it became possible to reconstruct the image viewed by the subject. The result was not a clear image, but a somewhat fuzzy speckle pattern. In this study, the researchers used hand-written letters.

Prior knowledge improves model performance
‘After this we did something new’, says lead researcher Marcel van Gerven. ‘We gave the model prior knowledge: we taught it what letters look like. This improved the recognition of the letters enormously. The model compares the letters to determine which one corresponds most exactly with the speckle image, and then pushes the results of the image towards that letter. The result was the actual letter, a true reconstruction.’

‘Our approach is similar to how we believe the brain itself combines prior knowledge with sensory information. For example, you can recognise the lines and curves in this article as letters only after you have learned to read. And this is exactly what we are looking for: models that show what is happening in the brain in a realistic fashion. We hope to improve the models to such an extent that we can also apply them to the working memory or to subjective experiences such as dreams or visualisations. Reconstructions indicate whether the model you have created approaches reality.’

Improved resolution; more possibilities
‘In our further research we will be working with a more powerful MRI scanner,’ explains Sanne Schoenmakers, who is working on a thesis about decoding thoughts. ‘Due to the higher resolution of the scanner, we hope to be able to link the model to more detailed images. We are currently linking images of letters to 1200 voxels in the brain; with the more powerful scanner we will link images of faces to 15,000 voxels.’

Autistic kids who best peers at math show different brain organization

Children with autism and average IQs consistently demonstrated superior math skills compared with nonautistic children in the same IQ range, according to a study by researchers at the Stanford University School of Medicine and Lucile Packard Children’s Hospital.

“There appears to be a unique pattern of brain organization that underlies superior problem-solving abilities in children with autism,” said Vinod Menon, PhD, professor of psychiatry and behavioral sciences and a member of the Child Health Research Institute at Packard Children’s.

The autistic children’s enhanced math abilities were tied to patterns of activation in a particular area of their brains — an area normally associated with recognizing faces and visual objects.

Menon is senior author of the study, published online Aug. 17 in Biological Psychiatry. Postdoctoral scholar Teresa luculano, PhD, is the lead author.

Children with autism have difficulty with social interactions, especially interpreting nonverbal cues in face-to-face conversations. They often engage in repetitive behaviors and have a restricted range of interests.

But in addition to such deficits, children with autism sometimes exhibit exceptional skills or talents, known as savant abilities. For example, some can instantly recall the day of the week of any calendar date within a particular range of years — for example, that May 21, 1982, was a Friday. And some display superior mathematical skills.

“Remembering calendar dates is probably not going to help you with academic and professional success,” Menon said. “But being able to solve numerical problems and developing good mathematical skills could make a big difference in the life of a child with autism.”

The idea that people with autism could employ such skills in jobs, and get satisfaction from doing so, has been gaining ground in recent years.

The participants in the study were 36 children, ages 7 to 12. Half had been diagnosed with autism. The other half was the control group. Each group had 14 boys and four girls. (Autism disproportionately affects boys.) All participants had IQs in the normal range and showed normal verbal and reading skills on standardized tests administered as part of the recruitment process for the study. But on the standardized math tests that were administered, the children with autism outperformed children in the control group.

After the math test, researchers interviewed the children to assess which types of problem-solving strategies each had used: Simply remembering an answer they already knew; counting on their fingers or in their heads; or breaking the problem down into components — a comparatively sophisticated method called decomposition. The children with autism displayed greater use of decomposition strategies, suggesting that more analytic strategies, rather than rote memory, were the source of their enhanced abilities.

Then, the children worked on solving math problems while their brain activity was measured in an MRI scanner, in which they had to lie down and remain still. The brain scans of the autistic children revealed an unusual pattern of activity in the ventral temporal occipital cortex, an area specialized for processing visual objects, including faces.

“Our findings suggest that altered patterns of brain organization in areas typically devoted to face processing may underlie the ability of children with autism to develop specialized skills in numerical problem solving,” Iuculano said.

“These findings not only empirically confirm that high-functioning children with autism have especially strong number-problem-solving abilities, but show that this cognitive strength in math is based on different patterns of functional brain organization,” said Carl Feinstein, MD, director of the Center for Autism and Related Disorders at Packard Children’s and professor of psychiatry and behavioral sciences at the School of Medicine. He was not involved in the study.

Menon added that previous research “has focused almost exclusively on weaknesses in children with autism. Our study supports the idea that the atypical brain development in autism can lead, not just to deficits, but also to some remarkable cognitive strengths. We think this can be reassuring to parents.”

The research team is now gathering data from a larger group of children with autism to learn more about individual differences in their mathematical abilities. Menon emphasized that not all children with autism have superior math abilities, and that understanding the neural basis of variations in problem-solving abilities is an important topic for future research.

(Image: Corbis)

Remembering to Remember Supported by Two Distinct Brain Processes

You plan on shopping for groceries later and you tell yourself that you have to remember to take the grocery bags with you when you leave the house. Lo and behold, you reach the check-out counter and you realize you’ve forgotten the bags.

Remembering to remember — whether it’s grocery bags, appointments, or taking medications — is essential to our everyday lives. New research sheds light on two distinct brain processes that underlie this type of memory, known as prospective memory.

The research is published in Psychological Science, a journal of the Association for Psychological Science.

To investigate how prospective memory is processed in the brain, psychological scientist Mark McDaniel of Washington University in St. Louis and colleagues had participants lie in an fMRI scanner and asked them to press one of two buttons to indicate whether a  word that popped up on a screen was a member of a designated category. In addition to this ongoing activity, participants were asked to try to remember to press a third button whenever a special target popped up. The task was designed to tap into participants’ prospective memory, or their ability to remember to take certain actions in response to specific future events.

When McDaniel and colleagues analyzed the fMRI data, they observed that two distinct brain activation patterns emerged when participants made the correct button press for a special target.

When the special target was not relevant to the ongoing activity — such as a syllable like “tor” — participants seemed to rely on top-down brain processes supported by the prefrontal cortex. In order to answer correctly when the special syllable flashed up on the screen, the participants had to sustain their attention and monitor for the special syllable throughout the entire task. In the grocery bag scenario, this would be like remembering to bring the grocery bags by constantly reminding yourself that you can’t forget them.

When the special target was integral to the ongoing activity—such as a whole word, like “table” — participants recruited a different set of brain regions, and they didn’t show sustained activation in these regions. The findings suggest that remembering what to do when the special target was a whole word didn’t require the same type of top-down monitoring. Instead, the target word seemed to act as an environmental cue that prompted participants to make the appropriate response – like reminding yourself to bring the grocery bags by leaving them near the front door.

“These findings suggest that people could make use of several different strategies to accomplish prospective memory tasks,” says McDaniel.

McDaniel and colleagues are continuing their research on prospective memory, examining how this phenomenon might change with age.

(Image: Shutterstock)

Two left feet? Study looks to demystify why we lose our balance

It’s always in front of a million people and feels like eternity. You’re strolling along when suddenly you’ve stumbled—the brain realizes you’re falling, but your muscles aren’t doing anything to stop it.

For a young person, a fall is usually just embarrassing. However, for the elderly, falling can be life threatening. Among the elderly who break a hip, 80 percent die within a year.

University of Michigan researchers believe that the critical window of time between when the brain senses a fall and the muscles respond may help explain why so many older people suffer these serious falls. A better understanding of what happens in the brain and muscles during this lag could go a long way toward prevention.

To that end, researchers at the U-M School of Kinesiology developed a novel way of looking at the electrical response in the brain before and during a fall by using an electroencephalogram.

Findings showed that many areas of the brain sense and respond to a fall, but that happens well before the muscles react. Lead researcher Daniel Ferris likened the study method to recording an orchestra with many microphones and then teasing out the sounds of specific instruments. In the study, researchers measured electrical activity in different regions of the brain.

"We’re using an EEG in a way others don’t, to look at what’s going on inside the brain," said Ferris, a professor in kinesiology. "We were able to determine what parts of the brain first identify when you are losing your balance during walking."

During the study, healthy young subjects with electrodes attached to their scalps walked on a balance beam mounted to a treadmill. When participants lost their balance and went off the beam, they simply continued walking on the moving treadmill, thus avoiding injury.

Ferris and colleagues then used a method called independent components analysis to separate and visualize the electrical activity in different parts of the brain. They found that people sense the start of a fall much better with both feet on the ground. Two grounded feet make it easier to determine where the ground is relative to the body, but people aren’t as sure of their stability on one foot.

The researchers were surprised that so many different parts of the brain activate during a fall, and they didn’t expect the brain to recognize a loss of balance as early as it does.

Future studies comparing the elderly with younger subjects could determine if the elderly sense falls too late, in which case, pharmaceuticals might help them regain their balance. If it’s a simple motor problem such as muscles not responding properly, strengthening exercises could help.

Other experiments under the same grant in the Ferris lab look to separate sensory and motor contributions to brain activity during walking.

The study, “Loss of balance during balance beam walking elicits a broadly distributed theta band electrocortical response,” was published in advance online in the Journal of Neurophysiology.

A hypnotic suggestion can generate true and automatic hallucinations

A multidisciplinary group of researchers from Finland (University of Turku and University of Helsinki) and Sweden (University of Skövde) has now found evidence that hypnotic suggestion can modify processing of a targeted stimulus before it reaches consciousness. The experiments show that it is possible to hypnotically modulate even highly automatic features of perception, such as color experience.  The results are presented in two articles published in PLoS ONE and International Journal of Clinical and Experimental Hypnosis. The Finnish part of the research is funded by the Academy of Finland.

The nature of hypnotically suggested changes in perception has been one of the main topics of controversy during the history of hypnosis. The major current theories of hypnosis hold that we always actively use our own imagination to bring about the effects of a suggestion. For example the occurrence of visual hallucinations always requires active use of goal directed imagery and can be experienced both with and without hypnosis.

The study published in PLoS ONE was done with two very highly hypnotizable participants who can be hypnotized and dehypnotized by just using a one-word cue.
The researchers measured brains oscillatory activity from the EEG in response to briefly displayed series of red or blue shapes (squares, triangles or circles). The participants were hypnotized and given a suggestion that certain shapes always have a certain color (e.g. all squares are always red). Participant TS-H reported constantly experiencing a change in color immediately when a suggested shape appeared on the screen (e.g. seeing a red square when the real color was blue). The researchers found that this experience was accompanied with enhanced high-frequency brain activity already 1/10 second after the stimulus appeared and it was only seen in response to the shapes mentioned in the suggestion. The second participant did not experience the color change or the enhanced activity. However, she reported a peculiar feeling when a suggestion-relevant shape was presented: “sometimes I saw a shape that was red but my brain told me it had a different color”.

This enhanced oscillatory brain activity is proposed to reflect automatic comparison of input to memory representations. In this case the hypnotic suggestion “all squares are red” led to a memory trace that was automatically activated when a square was presented. Furthermore, for the participant TS-H the effect was strong enough to override the real color of the square. The matching must have occurred preconsciously because of the early timing of the effect and the immediacy of the color change. Also, both participants reported having performed under posthypnotic amnesia without conscious memory of the suggestions.

In the article published in International Journal of Clinical and Experimental Hypnosis TS-H was tested in a similar type of setting, however, only behavioral data, including accuracy and response times in color recognition, were collected. These results further support that a hypnotic suggestion affects her color perception of targeted objects before she becomes conscious of them. Furthermore, TS-H was not capable of changing her experience of visually presented stable images without the use of hypnotic suggestions i.e. by using mere mental imagery.

Importantly, both of these experiments were done by using a posthypnotic suggestion. The effect was suggested during hypnosis but the experience was suggested to occur after hypnosis. Thus all the experiments were carried out while participants were in their normal state of consciousness.

This result indicates that all hypnotic responding can no longer be regarded merely as goal directed mental imagery.  It shows that in hypnosis it is possible to create a memory trace that influences early and preconscious stages of visual processing already about 1/10 second after the appearance of a visual target. This result has important implications in psychology and cognitive neuroscience especially when studying visual perception, memory and consciousness.

Electrical signatures of consciousness in the dying brain

A University of Michigan animal study shows high electrical activity in the brain after clinical death

The “near-death experience” reported by cardiac arrest survivors worldwide may be grounded in science, according to research at the University of Michigan Health System.

Whether and how the dying brain is capable of generating conscious activity has been vigorously debated.

But in this week’s PNAS Early Edition, a U-M study shows shortly after clinical death, in which the heart stops beating and blood stops flowing to the brain, rats display brain activity patterns characteristic of conscious perception.  

“This study, performed in animals, is the first dealing with what happens to the neurophysiological state of the dying brain,” says lead study author Jimo Borjigin, Ph.D., associate professor of molecular and integrative physiology and associate professor of neurology at the University of Michigan Medical School.  

“It will form the foundation for future human studies investigating mental experiences occurring in the dying brain, including seeing light during cardiac arrest,” she says.

Approximately 20 percent of cardiac arrest survivors report having had a near-death experience. These visions and perceptions have been called “realer than real,” according to previous research, but it remains unclear whether the brain is capable of such activity after cardiac arrest.

“We reasoned that if near-death experience stems from brain activity, neural correlates of consciousness should be identifiable in humans or animals even after the cessation of cerebral blood flow,” she says.

Researchers analyzed the recordings of brain activity called electroencephalograms (EEGs) from nine anesthetized rats undergoing experimentally induced cardiac arrest.

Within the first 30 seconds after cardiac arrest, all of the rats displayed a widespread, transient surge of highly synchronized brain activity that had features associated with a highly aroused brain.

Furthermore, the authors observed nearly identical patterns in the dying brains of rats undergoing asphyxiation.

“The prediction that we would find some signs of conscious activity in the brain during cardiac arrest was confirmed with the data,” says Borjigin, who conceived the idea for the project in 2007 with study co-author neurologist Michael M. Wang, M.D., Ph.D., associate professor of neurology and associate professor of molecular and integrative physiology at the U-M.

“But, we were surprised by the high levels of activity,” adds study senior author anesthesiologist George Mashour, M.D., Ph.D., assistant professor of anesthesiology and neurosurgery at the U-M. “ In fact, at near-death, many known electrical signatures of consciousness exceeded levels found in the waking state, suggesting that the brain is capable of well-organized electrical activity during the early stage of clinical death.­­­”

The brain is assumed to be inactive during cardiac arrest. However the neurophysiological state of the brain immediately following cardiac arrest had not been systemically investigated until now. 

The current study resulted from collaboration between the labs of Borjigin and Mashour, with U-M physicist UnCheol Lee, Ph.D., playing a critical role in analysis.

“This study tells us that reduction of oxygen or both oxygen and glucose during cardiac arrest can stimulate brain activity that is characteristic of conscious processing,” says Borjigin. “It also provides the first scientific framework for the near-death experiences reported by many cardiac arrest survivors.”

Our brains can (unconsciously) save us from temptation

Inhibitory self control – not picking up a cigarette, not having a second drink, not spending when we should be saving – can operate without our awareness or intention.

That was the finding by scientists at the University of Pennsylvania’s Annenberg School for Communication and the University of Illinois at Urbana-Champaign. They demonstrated through neuroscience research that inaction-related words in our environment can unconsciously influence our self-control. Although we may mindlessly eat cookies at a party, stopping ourselves from over-indulging may seem impossible without a deliberate, conscious effort. However, it turns out that overhearing someone – even in a completely unrelated conversation – say something as simple as “calm down” might trigger us to stop our cookie eating frenzy without realizing it.

The findings were reported in the journal Cognition by Justin Hepler, M.A., University of Illinois; and Dolores Albarracín, Ph.D., the Martin Fishbein Chair of Communication and a Professor of Psychology at Penn.

Volunteers completed a study where they were given instructions to press a computer key when they saw the letter “X” on the computer screen, or not press a key when they saw the letter “Y.” Their actions were affected by subliminal messages flashing rapidly on the screen. Action messages (“run,” “go,” “move,” “hit,” and “start”) alternated with inaction messages (“still,” “sit,” “rest,” “calm,” and “stop”) and nonsense words (“rnu,” or “tsi”). The participants were equipped with electroencephalogram recording equipment to measure brain activity.

The unique aspect of this test is that the action or inaction messages had nothing to do with the actions or inactions volunteers were doing, yet Hepler and Albarracín found that the action/inaction words had a definite effect on the volunteers’ brain activity. Unconscious exposure to inaction messages increased the activity of the brain’s self-control processes, whereas unconscious exposure to action messages decreased this same activity.

“Many important behaviors such as weight loss, giving up smoking, and saving money involve a lot of self-control,” the researchers noted. “While many psychological theories state that actions can be initiated automatically with little or no conscious effort, these same theories view inhibition as an effortful, consciously controlled process. Although reaching for that cookie doesn’t require much thought, putting it back on the plate seems to require a deliberate, conscious intervention. Our research challenges the long-held assumption that inhibition processes require conscious control to operate.”

The full article, “Complete unconscious control: Using (in)action primes to demonstrate completely unconscious activation of inhibitory control mechanisms,” will be available in the September issue of the journal.

(Image: Getty Images)

This is your brain on Vivaldi and Beatles

Listening to music activates large networks in the brain, but different kinds of music are processed differently. A team of researchers from Finland, Denmark and the UK has developed a new method for studying music processing in the brain during a realistic listening situation. Using a combination of brain imaging and computer modeling, they found areas in the auditory, motor, and limbic regions to be activated during free listening to music. They were furthermore able to pinpoint differences in the processing between vocal and instrumental music. The new method helps us to understand better the complex brain dynamics of brain networks and the processing of lyrics in music. The study was published in the journal NeuroImage.

Using functional magnetic resonance imaging (fMRI), the research team, led by Dr. Vinoo Alluri from the University of Jyväskylä, Finland, recorded the brain responses of individuals while they were listening to music from different genres, including pieces by Antonio Vivaldi, Miles Davis, Booker T. & the M.G.’s, The Shadows, Astor Piazzolla, and The Beatles. Following this, they analyzed the musical content of the pieces using sophisticated computer algorithms to extract musical features related to timbre, rhythm and tonality. Using a novel cross-validation method, they subsequently located activated brain areas that were common across the different musical stimuli.

The study revealed that activations in several areas in the brain belonging to the auditory, limbic, and motor regions were activated by all musical pieces. Notable, areas in the medial orbitofrontal region and the anterior cingulate cortex, which are relevant for self-referential appraisal and aesthetic judgments, were found to be activated during the listening. A further interesting finding was that vocal and instrumental music were processed differently. In particular, the presence of lyrics was found to shift the processing of musical features towards the right auditory cortex, which suggests a left-hemispheric dominance in the processing of the lyrics. This result is in line with previous research, but now for the first time observed during continuous listening to music.

"The new method provides a powerful means to predict brain responses to music, speech, and soundscapes across a variety of contexts", says Dr. Vinoo Alluri.