How does the cerebellum work?

Nothing says “don’t mess with me” like a deeply-fissured cortex. Even the sharpest jaws and claws in the animal kingdom are worthless without some serious thought muscle under the hood. But beneath the highly convoluted membrane covering the brains of the evolutionary upper crust hides the original crumpled processor—the cerebellum. How this organ might actually work is the subject of a review published in Frontiers of Systems Neuroscience by researchers at the University of Minnesota.

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Structurally-Constrained Relationships between Cognitive States in the Human Brain

The anatomical connectivity of the human brain supports diverse patterns of correlated neural activity that are thought to underlie cognitive function. In a manner sensitive to underlying structural brain architecture, we examine the extent to which such patterns of correlated activity systematically vary across cognitive states. Anatomical white matter connectivity is compared with functional correlations in neural activity measured via blood oxygen level dependent (BOLD) signals. Functional connectivity is separately measured at rest, during an attention task, and during a memory task. We assess these structural and functional measures within previously-identified resting-state functional networks, denoted task-positive and task-negative networks, that have been independently shown to be strongly anticorrelated at rest but also involve regions of the brain that routinely increase and decrease in activity during task-driven processes. We find that the density of anatomical connections within and between task-positive and task-negative networks is differentially related to strong, task-dependent correlations in neural activity. The space mapped out by the observed structure-function relationships is used to define a quantitative measure of separation between resting, attention, and memory states. We find that the degree of separation between states is related to both general measures of behavioral performance and relative differences in task-specific measures of attention versus memory performance. These findings suggest that the observed separation between cognitive states reflects underlying organizational principles of human brain structure and function.

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No such thing as a ‘universal’ intelligence test. Cultural differences determine results country by country

Researchers at the University of Granada have shown that a universal test of intelligence quotient (IQ) does not exist. Results in this type of test are determined by cultural differences.

Their objective was to study and explain cultural differences in IQ test performance. To do this, scientists from CIMCYC—the University of Granada’s Brain Mind and Behavior Research Center—conducted a study of 54 individuals aged between 18 and 54 years: 27 were Spanish and the other 27 were Moroccans residing in Spain.

The groups were selected to ensure that clear cultural differences existed between them: they spoke different languages (Spanish versus Arabic), professed different religions (Christians versus Muslims), had different traditions, and came from very different geographical contexts (Europe versus Africa).

Both groups underwent different tests of intellectual capacity: for example, a test of non-verbal intelligence, and various neuropsychological tests that measure functions such as visual memory and executive functions.

The same test measures different cognitive functions

Although the two groups were similar in terms of sex, educational level and socio-economic status, the results showed that in the test of non-verbal intelligence, the Spanish group obtained a higher IQ score than the Moroccan group. Moreover, the neuropsychological skills used in each subtest were clearly dependent on the country of origin of each participant. In other words, the same test can measure different cognitive functions in individuals from different cultures.

In the light of the results of this study, the authors suggest that the non-verbal tests cannot be considered culture-free and confirm the importance of validating the tests in their cultural context.

In 2014, this study has been ranked in the top 10 of articles downloaded from Archives of Clinical Neuropsychology.

The effects of working memory training on functional brain network efficiency

The human brain is a highly interconnected network. Recent studies have shown that the functional and anatomical features of this network are organized in an efficient small-world manner that confers high efficiency of information processing at relatively low connection cost. However, it has been unclear how the architecture of functional brain networks is related to performance in working memory (WM) tasks and if these networks can be modified by WM training. Therefore, we conducted a double-blind training study enrolling 66 young adults. Half of the subjects practiced three WM tasks and were compared to an active control group practicing three tasks with low WM demand. High-density resting-state electroencephalography (EEG) was recorded before and after training to analyze graph-theoretical functional network characteristics at an intracortical level. WM performance was uniquely correlated with power in the theta frequency, and theta power
was increased by WM training. Moreover, the better a person’s WM performance, the more their network exhibited small-world topology. WM training shifted network characteristics in the direction of high performers, showing increased small-worldness within a distributed fronto-parietal network. Taken together, this is the first longitudinal study that provides evidence for the plasticity of the functional brain network underlying WM.

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Overlapping Neural Systems Represent Cognitive Effort and Reward Anticipation

Anticipating a potential benefit and how difficult it will be to obtain it are valuable skills in a constantly changing environment. In the human brain, the anticipation of reward is encoded by the Anterior Cingulate Cortex (ACC) and Striatum. Naturally, potential rewards have an incentive quality, resulting in a motivational effect improving performance. Recently it has been proposed that an upcoming task requiring effort induces a similar anticipation mechanism as reward, relying on the same cortico-limbic network. However, this overlapping anticipatory activity for reward and effort has only been investigated in a perceptual task. Whether this generalizes to high-level cognitive tasks remains to be investigated. To this end, an fMRI experiment was designed to investigate anticipation of reward and effort in cognitive tasks. A mental arithmetic task was implemented, manipulating effort (difficulty), reward, and delay in reward delivery to control for temporal confounds. The goal was to test for the motivational effect induced by the expectation of bigger reward and higher effort. The results showed that the activation elicited by an upcoming difficult task overlapped with higher reward prospect in the ACC and in the striatum, thus highlighting a pivotal role of this circuit in sustaining motivated behavior.

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Blue light may fight fatigue around the clock

Researchers from Brigham and Women’s Hospital (BWH) have found that exposure to short wavelength, or blue light, during the biological day directly and immediately improves alertness and performance. These findings are published in the February issue of Sleep.

"Our previous research has shown that blue light is able to improve alertness during the night, but our new data demonstrates that these effects also extend to daytime light exposure," said Shadab Rahman, PhD, a researcher in BWH’s Division of Sleep Medicine and lead author of this study. "These findings demonstrate that prolonged blue light exposure during the day has an an alerting effect."

In order to determine which wavelengths of light were most effective in warding off fatigue, the BWH researchers teamed with George Brainard, PhD, a professor of neurology at Thomas Jefferson University, who developed the specialized light equipment used in the study. Researcherscompared the effects of blue light with exposure to an equal amount of green light on alertness and performance in 16 study participants for 6.5 hours over a day. Participants then rated how sleepy they felt, had their reaction times measured and wore electrodes to assess changes in brain activity patterns during the light exposure.

The researchers found that participants exposed to blue light consistently rated themselves as less sleepy, had quicker reaction times and fewer lapses of attention during the performance tests compared to those who were exposed to green light. They also showed changes in brain activity patterns that indicated a more alert state.

"These results contribute to our understanding of how light impacts the brain and open up a new range of possibilities for using light to improve human alertness, productivity and safety," explained Steven Lockley, PhD, neuroscientist at BWH and senior investigator of the study. "While helping to improve alertness in night workers has obvious safety benefits, day shift workers may also benefit from better quality lighting that would not only help them see better but also make them more alert."

Researchers note that the next big challenge is to figure out how to deliver better lighting. While natural light is ideal, many people do not have access to daylight in their schools, homes or work places. In addition to improvements in daylight access, the advent of new, more controllable lighting technologies may help enable researchers to develop ‘smart’ lighting systems designed to maximize the beneficial effects of light for human health, productivity and safety.

Scientific study suggests an association between physical doping and brain doping

Physical doping and brain doping apparently often go hand in hand. A study from Johannes Gutenberg University Mainz (JGU) and Eberhard Karls University in Tubingen revealed that people who engage in physical doping often also take drugs for brain doping. The study was the first of its kind to survey simultaneously the two categories of doping and brain doping. Around 3,000 hobby triathletes were anonymously surveyed using a questionnaire at sporting events in Frankfurt, Regensburg, and Wiesbaden. “The results correlated with earlier findings about doping in leisure and popular sports and brain doping in society as a whole. The findings also illustrated for the first time that physical doping and brain doping often go together, at least for recreational triathletes,” said Mainz University Professor of Sports Medicine Dr. Dr. Perikles Simon.

The study was carried out using the randomized response technique (RRT), which allows for better estimates of unknown cases in response to sensitive questions. It suggested that 13.0 percent of the athletes surveyed had used illegal and banned substances in the twelve months prior to the survey; 15.1 percent were believed to have engaged in brain doping.

When talking about doping substances, a distinction is made between illicit drugs such as cocaine or heroin and banned substances for physical performance enhancement such as anabolic steroids, EPO, or growth hormones. Brain doping is the use of illegal substances and pharmaceuticals such as illegal amphetamines, modafinil or Ritalin to improve mental performance.

The findings indicate that the estimated proportion of men who dope (13.7 percent) is higher than the proportion of women (8.0 percent). The prevalence of doping also seemed to be higher at the European Championships in Frankfurt than at the other triathlons in Regensburg and Wiesbaden. The competitions involved participants taking part in either a classic Ironman with a 4 kilometer swim, 180 kilometer cycle ride, and 42 kilometer marathon or tackling half of the actual Ironman distance.

In their survey carried out during the 2011 season, the scientists interviewed a total of 2,997 triathlon participants. 2,987 questionnaires (99.7 percent) were returned. The study also examined whether there was a correlation between the use of legal and freely available substances for improving physical and mental performance and the use of illegal and banned substances. This would appear to be the case, as athletes who use legal substances to improve their performance also tend to use illegal substances as well.

Finally, another important finding of the study was the sign of a correlation between physical doping and brain doping, which can be found with both legal and illicit substances. The use of legal substances to enhance physical performance is thus relatively often associated with the consumption of substances to improve mental performance, just as there is a correlation between the use of illicit substances for both doping and brain doping. “This indicates that athletes do not actually take the substances to achieve a specific goal, but may show a certain propensity towards performance enhancing substances,” explained Simon. The findings are important to better understand why people take such substances and to be able to provide targeted prevention.

Picking up mistakes

Musicians have sharper minds are able to pick up mistakes and fix them quicker than the rest of us, according to new research.

The study, by researchers at the University of St Andrews, suggests that musical activity could protect against decline in mental abilities through age or illness.

The work, published in the journal Neuropsychologia, extends previous findings that mental abilities are positively related to musical skills. The researchers say that the latest findings demonstrate the potential for ‘far reaching benefits’ of musical activity on mental and physical well-being.

The study was led by St Andrews psychologist Dr Ines Jentzsch, who compared the cognitive ability of amateur musicians versus non-musicians in performing simple mental tasks.

The most striking difference she found lay in the musicians’ ability to recognise and correct mistakes. Not only that, but they responded faster than those with little or no musical training, with no loss in accuracy. This is perhaps not surprising since musicians learn to be constantly aware of their performance, but to not be overly affected by mistakes.

Dr Jentzsch, a Reader in the University’s School of Psychology and Neuroscience, commented, “Our study shows that even moderate levels of musical activity can benefit brain functioning.

“Our findings could have important implications as the processes involved are amongst the first to be affected by aging, as well as a number of mental illnesses such as depression. The research suggests that musical activity could be used as an effective intervention to slow, stop or even reverse age- or illness-related decline in mental functioning.”

The study compared groups of amateur musicians with varying levels of time they had spent in practicing their instrument to a non-musician control group. They then measured each group’s behavioural and brain responses to simple mental tests.

The results showed that playing a musical instrument, even at moderate levels, improves the ability to monitor our behavior for errors and adjust subsequent responses more effectively when needed.

Dr Jentzsch, herself a keen pianist, continued, “Musical activity cannot only immensely enrich our lives but the associated benefits for our physical and mental functioning could be even more far-reaching than proposed in our and previous research.

“Music plays an important role in virtually all societies. Nevertheless, in times of economic hardship, funds for music education are often amongst the first to be cut.

“We strongly encourage political decision makers to reconsider funding cuts for arts education and to increase public spending for music tuition.

“In addition, adults who have never played an instrument or felt too old to learn should be encouraged to take up music - it’s never too late.”