A rich vocabulary can protect against cognitive impairment

Some people suffer incipient dementia as they get older. To make up for this loss, the brain’s cognitive reserve is put to the test. Researchers from the University of Santiago de Compostela have studied what factors can help to improve this ability and they conclude that having a higher level of vocabulary is one such factor.

‘Cognitive reserve’ is the name given to the brain’s capacity to compensate for the loss of its functions. This reserve cannot be measured directly; rather, it is calculated through indicators believed to increase this capacity.

A research project at the University of Santiago de Compostela (USC) has studied how having a wide vocabulary influences cognitive reserve in the elderly.

As Cristina Lojo Seoane, from the USC, co-author of the study published in the journal ‘Anales de Psicología’(Annals of Psychology), explains to SINC: “We focused on level of vocabulary as it is considered an indicator of crystallised intelligence (the use of previously acquired intellectual skills). We aimed to deepen our understanding of its relation to cognitive reserve.”

The research team chose a sample of 326 subjects over the age of 50 – 222 healthy individuals and 104 with mild cognitive impairment. They then measured their levels of vocabulary, along with other measures such as their years of schooling, the complexity of their jobs and their reading habits.

They also analysed the scores they obtained in various tests, such as the vocabulary subtest of the ‘Wechsler Adult Intelligence Scale’(WAIS) and the Peabody Picture Vocabulary Test.

“With a regression analysis we calculated the probability of impairment to the vocabulary levels of the participants,” Lojo Seoane continues.

The results revealed a greater prevalence of mild cognitive impairment in participants who achieved a lower vocabulary level score.

“This led us to the conclusion that a higher level of vocabulary, as a measure of cognitive reserve, can protect against cognitive impairment,” the researcher concludes.

Mental Rest and Reflection Boost Learning

A new study, which may have implications for approaches to education, finds that brain mechanisms engaged when people allow their minds to rest and reflect on things they’ve learned before may boost later learning.

Scientists have already established that resting the mind, as in daydreaming, helps strengthen memories of events and retention of information. In a new twist, researchers at The University of Texas at Austin have shown that the right kind of mental rest, which strengthens and consolidates memories from recent learning tasks, helps boost future learning.

The results appear online this week in the journal Proceedings of the National Academy of Sciences.

Margaret Schlichting, a graduate student researcher, and Alison Preston, an associate professor of psychology and neuroscience, gave participants in the study two learning tasks in which participants were asked to memorize different series of associated photo pairs. Between the tasks, participants rested and could think about anything they chose, but brain scans found that the ones who used that time to reflect on what they had learned earlier in the day fared better on tests pertaining to what they learned later, especially where small threads of information between the two tasks overlapped. Participants seemed to be making connections that helped them absorb information later on, even if it was only loosely related to something they learned before.

"We’ve shown for the first time that how the brain processes information during rest can improve future learning," says Preston. "We think replaying memories during rest makes those earlier memories stronger, not just impacting the original content, but impacting the memories to come.

Until now, many scientists assumed that prior memories are more likely to interfere with new learning. This new study shows that at least in some situations, the opposite is true.

"Nothing happens in isolation," says Preston. "When you are learning something new, you bring to mind all of the things you know that are related to that new information. In doing so, you embed the new information into your existing knowledge."

Preston described how this new understanding might help teachers design more effective ways of teaching. Imagine a college professor is teaching students about how neurons communicate in the human brain, a process that shares some common features with an electric power grid. The professor might first cue the students to remember things they learned in a high school physics class about how electricity is conducted by wires.

"A professor might first get them thinking about the properties of electricity," says Preston. "Not necessarily in lecture form, but by asking questions to get students to recall what they already know. Then, the professor might begin the lecture on neuronal communication. By prompting them beforehand, the professor might help them reactivate relevant knowledge and make the new material more digestible for them."

This research was conducted with adult participants. The researchers will next study whether a similar dynamic is at work with children.

How the brain leads us to believe we have sharp vision

We assume that we can see the world around us in sharp detail. In fact, our eyes can only process a fraction of our surroundings precisely. In a series of experiments, psychologists at Bielefeld University have been investigating how the brain fools us into believing that we see in sharp detail. The results have been published in the scientific magazine ‘Journal of Experimental Psychology: General.’ Its central finding is that our nervous system uses past visual experiences to predict how blurred objects would look in sharp detail.

"In our study we are dealing with the question of why we believe that we see the world uniformly detailed," says Dr. Arvid Herwig from the Neuro-Cognitive Psychology research group of the Faculty of Psychology and Sports Science. The group is also affiliated to the Cluster of Excellence Cognitive Interaction Technology (CITEC) of Bielefeld University and is led by Professor Dr. Werner X. Schneider.

Only the fovea, the central area of the retina, can process objects precisely. We should therefore only be able to see a small area of our environment in sharp detail. This area is about the size of a thumb nail at the end of an outstretched arm. In contrast, all visual impressions which occur outside the fovea on the retina become progressively coarse. Nevertheless, we commonly have the impression that we see large parts of our environment in sharp detail.

Herwig and Schneider have been getting to the bottom of this phenomenon with a series of experiments. Their approach presumes that people learn through countless eye movements over a lifetime to connect the coarse impressions of objects outside the fovea to the detailed visual impressions after the eye has moved to the object of interest. For example, the coarse visual impression of a football (blurred image of a football) is connected to the detailed visual impression after the eye has moved. If a person sees a football out of the corner of her eye, her brain will compare this current blurred picture with memorised images of blurred objects. If the brain finds an image that fits, it will replace the coarse image with a precise image from memory. This blurred visual impression is replaced before the eye moves. The person thus thinks that she already sees the ball clearly, although this is not the case.

The psychologists have been using eye-tracking experiments to test their approach. Using the eye-tracking technique, eye movements are measured accurately with a specific camera which records 1000 images per second. In their experiments, the scientists have recorded fast balistic eye movements (saccades) of test persons. Though most of the participants did not realise it, certain objects were changed during eye movement. The aim was that the test persons learn new connections between visual stimuli from inside and outside the fovea, in other words from detailed and coarse impressions. Afterwards, the participants were asked to judge visual characteristics of objects outside the area of the fovea. The result showed that the connection between a coarse and detailed visual impression occurred after just a few minutes. The coarse visual impressions became similar to the newly learnt detailed visual impressions.

"The experiments show that our perception depends in large measure on stored visual experiences in our memory," says Arvid Herwig. According to Herwig and Schneider, these experiences serve to predict the effect of future actions ("What would the world look like after a further eye movement"). In other words: "We do not see the actual world, but our predictions."

Legendary Marshmallow Test Yields Lessons for Everyday Challenges in Self-Control

Walter Mischel, the psychologist renowned for the groundbreaking study known as the “marshmallow test,” has finally decided to tell the story of that research for a general audience.

He dedicates the book, aptly titled The Marshmallow Test: Mastering Self-Control, to his now-grown daughters, saying they inspired him when they were young to study self-control in preschoolers.

“I saw dramatic changes in my own children,” says Mischel, the Robert Johnston Niven Professor of Humane Letters in Columbia’s Psychology Department. “I realized I was quite clueless about what was going on in their heads.”

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Gaming vs. reading: Do they benefit teenagers with cognition or school performance?

Children have an increasing attraction towards electronic media in their play. With video games, phones and the internet in abundance, this article in Educational Psychology examines if such leisure activity is impacting children’s cognition or academic performance or whether it would be more beneficial to read.

After a busy day children do need downtime to rest and relax.  Increasingly kids leisure time is spent gaming, but does it detract from homework or would kids be better off reading a book? Historical research shows in some cases that interactive gaming can have positive effects for cognition by promoting memory, attention and reasoning. Other speed oriented games have been shown to improve perception and motor skills, so should gaming for relaxation be encouraged? Lieury et al investigate whether type of leisure activity produces a ‘transfer effect’ influencing learning processes thus improving student performance at school. With an emphasis on gaming and reading they linked patterns of leisure activity with performance in phonology, reading and comprehension, maths, long term memory and reasoning. Fascinatingly gaming previously thought to improve fluid intelligence showed little or no positive correlations to performance whilst reading did, particularly in memory and comprehension. It seems then despite lack of a causal link that reading may be more likely to enhance academic performance.

Should we assume that time spent gaming and away from homework is harmful to students? A further comparison of reading and gaming to most frequent leisure activities showed no negative patterns but interestingly resting had a favourable effect on performance as well as reading. So frequent leisure activity is not necessarily harmful to progress, or always at the expense of homework but can be enriching. The authors conclude “we think that video games are mainly recreational activities and the cognitive stimulation provided is very different from school learning. On the contrary, the results of this survey fully justify the educational role of parents and teachers in promoting reading.”

(Image: Shutterstock)

Strong working memory put brakes on problematic drug use

Adolescents with strong working memory are better equipped to escape early drug experimentation without progressing into substance abuse issues, says a University of Oregon researcher.

Most important in the picture is executive attention, a component of working memory that involves a person’s ability to focus on a task and ignore distractions while processing relevant goal-oriented information, says Atika Khurana, a professor in the Department of Counseling Psychology and Human Services.

Khurana, also a member of the UO’s Prevention Science Institute, is lead author of a study online ahead of print in the quarterly journal Development and Psychopathology. The findings, drawn from a long-term study of 382 adolescents in a mostly at-risk urban population, provide a rare, early view of adolescents’ entry into the use of alcohol, tobacco and marijuana.

Khurana collaborated with researchers at the University of Pennsylvania and Children’s Hospital of Philadelphia. They focused on 11- to 13-year-old children as they began to explore risky and sensation-seeking experiences that often mark the road to independence and adulthood. Previous studies generally have relied on adult recall of when individuals began experimenting, with early drug use thought to be a marker of later substance abuse problems.

"Not all forms of early drug use are problematic," Khurana said. "There could be some individuals who start early, experiment and then stop. And there are some who could start early and go on into a progressive trajectory of continued drug use. We wanted to know what separates the two?"

During four assessments, participants provided self-reports of drug use in the previous 30 days. Four working memory tests also were conducted: Corsi block tapping, in which subjects viewed identical blocks that lit up randomly on a screen and tapped each box in reverse order of the lighting sequence; a digit-span test where numbers shown are to be repeated in reverse order; a letter two-back test, in which subjects identify specific letters in time-sensitive sequences; and a spatial working-memory task where hidden tokens must be found quickly within sets of four to eight randomly positioned boxes on a computer screen.

The pattern that emerged was that early drug experimentation more likely to lead into progressive drug use among young people whose impulsive tendencies aren’t kept in check by strong working memory ability. Later assessments of the participants, who have now reached late adolescence, are being analyzed, but it appears that the compulsive progression, not just the experimentation, of drug use is likely to lead to disorder, Khurana said.

"Prefrontal regions of the brain can apply the brakes or exert top-down control over impulsive, or reward seeking urges," Khurana said. "By its nature, greater executive attention enables one to be less impulsive in one’s decisions and actions because you are focused and able to control impulses generated by events around you. What we found is that if teens are performing poorly on working memory tasks that tap into executive attention, they are more likely to engage in impulsive drug-use behaviors."

The findings suggest new approaches for early intervention since weaknesses in executive functioning often underlie self-control issues in children as young as 3 years old, she said. A family environment strong in structured routines and cognitive-stimulation could strengthen working memory skills, she said.

For older children, interventions could be built around activities that encourage social competence and problem solving skills in combination with cognition-building efforts to increase self-control and working memory. The latter allows people to temporarily store, organize and manipulate mental information and is vital for evaluating consequences of decisions.

"We need to compensate for the weakness that exists, before drug experimentation starts to help prevent the negative spiral of drug abuse," Khurana said.

Americans Reporting Increased Symptoms of Depression

Strategic or Random? How the Brain Chooses

Many of the choices we make are informed by experiences we’ve had in the past. But occasionally we’re better off abandoning those lessons and exploring a new situation unfettered by past experiences. Scientists at the Howard Hughes Medical Institute’s Janelia Research Campus have shown that the brain can temporarily disconnect information about past experience from decision-making circuits, thereby triggering random behavior.

In the study, rats playing a game for a food reward usually acted strategically, but switched to random behavior when they confronted a particularly unpredictable and hard-to-beat competitor. The animals sometimes got stuck in a random-behavior mode, but the researchers, led by Janelia lab head Alla Karpova and postdoctoral fellow Gowan Tervo, found that they could restore normal behavior by manipulating activity in a specific region of the brain. Because the behavior of animals stuck in this random mode bears some resemblance to that of patients affected by a psychological condition called learned helplessness, the findings may help explain that condition and suggest strategies for treating it. Karpova, Tervo and their colleagues published their findings in the September 25, 2012, issue of the journal Cell.

The brain excels at integrating information from past experiences to guide decision-making in new situations. But in certain circumstances, random behavior may be preferable. An animal might have the best chance of avoiding a predator if it moves unpredictably, for example. And in a new environment, unrestricted exploration might make more sense than relying on an internal model developed elsewhere. So scientists have long speculated that the brain may have a way to switch off the influence of past experiences so that behavior can proceed randomly, Karpova says. But others disagreed. “They argue that it’s inefficient, and that it would be at odds with what some people call one of the most central operating principles of the brain – to use our past experience and knowledge to optimize behavioral choices,” she notes.

Karpova and her colleagues wanted to see if they could create a situation that would force animals to switch into this random mode of behavior. “We tried to create a setting that would push the need to create behavioral variability and unpredictability to its extreme,” she says. They did this by placing rats in a competitive setting in which a computer-simulated competitor determined which of two holes in a wall would provide a sugary reward. The virtual competitor, whose sophistication was varied by the experimenters, analyzed the rats’ behavior to predict their future choices.

“We thought if we came up with very sophisticated competitors, then the animals would eventually be unable to figure out how to outcompete them, and be forced to either give up or switch into this [random] mode, if such a mode exists,” Karpova says. And that’s exactly what happened: When faced with a weak competitor, the animals made strategic choices based on the outcomes of previous trials. But when a sophisticated competitor made strong predictions, the rats ignored past experience and made random selections in search of a reward.

Now that they had evidence that the brain could generate both strategic and random behavior, Karpova and her colleagues wanted to know how it switched between modes. Since that switch determines whether or not an animal’s internal model of the world influences its behavior, the scientists suspected it might involve a brain region called the anterior cingulate cortex, where that internal model is likely encoded.

They found that they could cause animals to switch between random and strategic behavior by manipulating the level of a stress hormone called norepinephrine in the anterior cingulate cortex. Increasing norepinephrine in the region activated random behavior and suppressed the strategic mode.  Inhibiting release of the hormone had the opposite effect.

Karpova’s team observed that animals in their experiments sometimes continued to behave randomly, even when such behavior was no longer advantageous. “If all they’ve experienced is this really sophisticated competitor for several sessions that thwarts their attempts at strategic, model-based counter-prediction, they go into this [random mode], and they can get stuck in it for quite some time after that competitor is gone,” she says. This, she says, resembles the condition of learned helplessness, in which strategic decision-making is impaired following an experience in which a person finds they are unable to control their environment.

The scientists could release the animals from this “stuck” state by suppressing the release of norepinephrine in the anterior cingulate cortex. “Just by manipulating a single neuromodulatory input into one brain area, you can dramatically enhance the strategic mode. The effect is strong enough to rescue animals out of the random mode and successfully transform them into strategic decision makers,” Karpova says. “We think this might shed light on what has gone wrong in conditions such as learned helplessness, and possibly how we can help alleviate them.” 

Karpova says that now that her team has uncovered a mechanism that switches the brain between random and strategic behavior, she would like to understand how those behaviors are controlled in more natural settings. “We normally try to use all of our knowledge to think strategically, but sometimes we still need to explore,” she says. In most cases, that probably means brief bouts of random behavior during times when we are uncertain that past experience is relevant, followed by a return to more strategic behavior – a more subtle balance that Karpova intends to investigate at the level of changes in activity in individual neural circuits.