Thursday, May 25, 2017

Learning to read in adulthood transforms brain: study

The human brain can adapt and transform itself based on external stimulus well into adulthood, researches have found.

A study of women in India who learned to read in their 30s shows the human brain's incredible capacity to reorganise and transform itself, researchers said today.

Researchers recruited women in India, a country with an illiteracy rate of around 39 percent, to see what they could learn about the areas of the brain devoted to reading.

At the start of the study, most of the women could not read a word of their mother tongue, Hindi.

But after six months of training, the women reached a level comparable to first-grade proficiency.

"This growth of knowledge is remarkable", said Falk Huettig from the Max Planck Institute for Psycholinguistics, lead author of the study in the journal Science Advances.

"While it is quite difficult for us to learn a new language, it appears to be much easier for us to learn to read. The adult brain proves to be astonishingly flexible."

Specifically, researchers found that the exterior of the brain - known as the cortex, which is able to adapt quickly to new challenges - was not the main area where transformation occurred.

Instead, researchers found that reorganisation took place deep inside the brain, particularly in the brainstem and thalamus, a walnut-sized structure that relays sensory and motor information.

"We observed that the so-called colliculi superiores, a part of the brainstem, and the pulvinar, located in the thalamus, adapt the timing of their activity patterns to those of the visual cortex," said co-author Michael Skeide, a scientific researcher at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig.

"These deep structures in the thalamus and brainstem help our visual cortex to filter important information from the flood of visual input even before we consciously perceive it." Researchers found that the more signals aligned in the affected brain regions, the better the women's reading skills became.

"These brain systems increasingly fine-tune their communication as learners become more and more proficient in reading," Skeide added.

"This could explain why experienced readers navigate more efficiently through a text." The finding could also have implications for the treatment of dyslexia, which some researchers have blamed on a malfunctioning thalamus.

"Since we found out that only a few months of reading training can modify the thalamus fundamentally, we have to scrutinise this hypothesis," Skeide said.

Co-authors on the study came from India's Centre of Bio- Medical Research (CBMR) Lucknow and the University of Hyderabad.

No evidence that brain-stimulation technique boosts cognitive training

Transcranial direct-current stimulation (tDCS)--a non-invasive technique for applying electric current to areas of the brain--may be growing in popularity, but new research suggests that it probably does not add any meaningful benefit to cognitive training. The study is published in Psychological Science, a journal of the Association for Psychological Science.

"Our findings suggest that applying tDCS while older participants engaged in daily working memory training over four weeks did not result in improved cognitive ability," explains researcher Martin Lövdén of Karolinska Institutet and Stockholm University.

"The study is important because it addresses what has arguably been the most promising cognitive application of tDCS: the possibility of long-term cognitive enhancement from relatively limited practice on select cognitive tasks," Lövdén adds. "Cognitive enhancement is of interest not just to scientists, but also to the student studying for final exams, the gamer playing online games, and the retiree remembering which pills to take. Because of this large audience, it is of utmost importance to conduct systematic research to disentangle hype from fact."

Working memory--our capacity for holding information in mind at any given moment--underlies many fundamental cognitive processes and is linked with some aspects of intelligence. Research has shown that working memory training improves working memory performance but it's unclear whether this specific training can yield improvements to broader cognitive abilities.

Recent interest and publicity surrounding the potential effects of tDCS--which involves conducting a weak electrical current to the brain via electrodes on the scalp--led Lövdén and colleagues to wonder: Could using tDCS during cognitive training enhance brain plasticity and enable transfer from working memory to other cognitive processes?

The researchers enrolled 123 healthy adults who were between 65 and 75 years old in a 4-week training program. All participants completed a battery of cognitive tests, which included tasks that were incorporated in the training and tasks that were not, at the beginning of the study and again at the end. Those randomly assigned to the experimental group trained on tasks that targeted their ability to update mental representations and their ability to switch between different tasks and rules, while those in the active control group trained on tasks that focused on perceptual speed.

As they completed the training tasks, some participants received 25 minutes of tDCS current to the left dorsolateral prefrontal cortex, an area of the brain that plays a central role in working memory; other participants were led to believe they were receiving 25 minutes of current, when in actuality the current was only active for a total 30 seconds.

Comparing participants' performance before and after training indicated that those who received working memory training did improve on the updating and switching tasks they had encountered during training and on similar tasks that they had not encountered previously.

But there was no evidence that tDCS produced any additional benefit to the working memory training--at the end of the study, participants who received tDCS did not show greater improvement than their peers.

When the researchers pooled the data from this study with findings from six other studies, they again found no evidence of any additional benefit from working memory training that was combined with tDCS.

Given strong public interest in cognitive enhancement, Lövdén and colleagues urge caution when it comes to this as-of-yet unproven application of tDCS:

"A growing number of people in the general public, presumably inspired by such uninhibited optimism, are now using tDCS to perform better at work or in online gaming, and online communities offer advice on the purchase, fabrication, and use of tDCS devices," the researchers write. "Unsurprisingly, commercial exploitation is rapidly being developed to meet this new public demand for cognitive enhancement via tDCS, often without a single human trial to support the sellers' or manufacturers' claims."

"These findings highlight exactly how limited our knowledge is of the mechanisms underlying the potential effects of tDCS on human cognition and encourages the research community to take a step back and focus its resources on developing strategies for uncovering such mechanisms before using the technique in more applied settings," Lövdén concludes.

Co-authors on the study include Jonna Nilsson, Alexander V. Lebedev, and Anders Rydström of Karolinska Institutet and Stockholm University.

This research received funding from the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP7/2007-2013) and ERC Grant No. 617280 -REBOOT. Martin Lövdén was also supported by a Distinguished Young Researchers grant from the Swedish Research Council (446-2013-7189).

For more information about this study, please contact: Martin Lövdén at

The article abstract are available online:

The APS journal Psychological Science is the highest ranked empirical journal in psychology. For a copy of the article "Direct-Current Stimulation Does Little to Improve the Outcome of Working Memory Training in Older Adults" and access to other Psychological Science research findings, please contact Anna Mikulak at 202-293-9300 or

Your Brain Is Trying to Show You The Future - And It Might Save Your Life

Our brains are pretty good at filling in the blanks when it comes to our sense of perception - often to the point we have a mental movie of an entire event before it even finishes unfolding.

New research has shown this 'mind's eye' prediction of future motion occurs at a higher speed than in reality - a trait we could have evolved to compensate for our relatively sluggish sense of vision.

Unless you have a condition called aphantasia, which makes it impossible to summon up mental images, you'll be familiar with how your visual cortex builds imagined scenes in your mind.

Until now, most research on the imagery that arises in anticipation of an ongoing event - or "preplay" - has been conducted on animals. This new study takes a close look at what's going on in the visual cortex of humans.

Researchers from Radboud University in the Netherlands put 29 university students into a functional magnetic resonance imaging (fMRI) scanner to map their brain activity as they watched a white dot step across a screen.

Participants were asked to watch the same animation repeat 108 times over a number of short sessions. By the end, their brains were very well primed to know what to expect as the dot travelled left to right and right to left in about half a second.

Now they had built in these expectations, the participants watched a random sequence of 24 'dot' movies. Some were just like the previous ones, with the dot moving across the screen, while others had the dots in the starting or ending positions only, plus a few 'oddball' trials delaying the final step in the movement sequence.

The entire experiment was conducted twice with each student, while another four volunteers acted as controls to rule out residual effects between the trials.

A series of fMRI scans were taken of their brains at ultra-fast speed to capture the blood flow in certain tissues.

As the volunteers watched the dots jump, a corresponding part of their visual cortex lit up with each step.

When shown just the starting dot, the same parts of the brain were activated, mentally completing the sequence in anticipation, though at twice the speed of the actual dot sequences.

The diagrams below give you some impression of how the brain scans of watching the moving dots compared to the scans of the volunteers when they were simply anticipating movement - in 'preplay'"

That isn't to say we can put a number on how fast 'fast-forward' is, since the fMRI scanner can only take snapshots at a certain speed, even on ultra-fast.

But it does suggest that we have a way to quickly visualise relatively simple movements, such as a ball rushing at our head, in at least half the time it would take for the event to occur.

Previous studies have estimated a need to look at an image for at least 150 milliseconds in order for our brains to capture enough information to make a judgement on what to look at next.

Then a study a few years ago found we can actually accomplish the task a lot faster - in just 13 milliseconds - at the risk of making some mistakes. That's quick, though processing lots of visual information quickly comes at a cost of chewing up more energy.

Nonetheless, it still means we're living up to a tenth of a second in the past, which could make all the difference between life and death.

It's possible that we evolved this ability to predict the future in fast-forward to save time and effort, helping us act sooner.

"Imagine you are standing at a road, a car is approaching and you need to decide "Do I cross, or do I wait for the car to pass first?"," lead researcher Matthias Ekman told MailOnline.

"Our study suggests that our visual system can fast-forward the trajectory of the car and thereby help us with our decision whether to wait or not."

The research calls into question the role of our visual cortex not just in perceiving current events, but in using past experiences to build perceptions of future ones.

"Thus, the notion of preplay processes in the visual system blurs the boundaries between memory and perception, and underscores the integrated nature of these two cognitive faculties," the researchers write in their report.

It pays to remain a little sceptical about conclusions on any relationship between higher blood-flow across specific bits of the brain and the part's role in a cognitive task, especially while questions remain on how closely linked metabolism is with the neural activity.

But if you've ever experienced the illusion of time standing still, you'll know our brains have some weird and remarkable tricks to cope with a fast paced world rushing past our eyes.