Category: Intelligence

The Stripe of Gennari develops even in those who are blind from birth and does not degenerate, despite a lack of visual input. This was discovered by Robert Trampel and colleagues from the Max Planck Institute for Human Cognitive and Brain Sciences using magnetic resonance imaging. This bundle of nerve fibers, which is approximately 0.3 mm thick, is not exclusively responsible for optic information.

In the blind, it might play a greater role in processing tactile stimuli. This could contribute to an enhanced sense of touch and support fast reading of Braille. (Cerebral Cortex, Online 10. 02. 2011)

The Stripe of Gennari — also known as the 'Stria of Gennari' — transverses the gray matter of the primary visual cortex as a distinct white line. "Although the visual cortex is one of the best-studied parts of the brain, and the Stripe of Gennari is a rather obvious structure, why it develops and what its function is has not previously been studied in detail," explains Robert Trampel from the Max Planck Institute for Human Cognitive and Brain Sciences. "An obvious connection with sight was assumed."

However, as is now clear, this cannot be the only function of the stripe of Gennari: In a functional magnetic resonance imaging (fMRI) study, the researchers found the stripe of Gennari in the brains of congenitally blind subjects. "This brain structure therefore can't exclusively be involved in vision and must be capable of carrying out other tasks," says Trampel. In the blind, the Stripe of Gennari could play a role in supporting the sense of touch, the scientists speculate. "This faculty is essential in reading Braille and the region carrying the Gennari-Stripe is known to show an increased activity in the blind when performing this task." All participants in the present study were highly proficient in reading Braille, having responded to an advertisement written in Braille in a newspaper for the visually impaired.

However, since the stripe of Gennari is already present in the first years of life and does not degenerate, it is likely to have an important role already in early infancy. In blind people, the brain uses tactile and acoustic stimuli to construct a rough spatial representation of the surroundings in the absence of visual information. The stripe of Gennari might play a role in this process and could later support highly demanding tactile tasks, like Braille-reading. In future studies with fMRI, the researchers aim to learn more about the work of this versatile nerve bundle in the human brain.

Journal Reference:

1. R. Trampel, D. V. M. Ott, R. Turner. Do the Congenitally Blind Have a Stria of Gennari? First Intracortical Insights In Vivo. Cerebral Cortex, 2011; DOI: 10.1093/cercor/bhq282

NewsPsychology (Feb. 11, 2011) — Regular exercise improves the ability of overweight, previously inactive children to think, plan and even do math, Georgia Health Sciences University researchers report.

They hope the findings in 171 overweight 7- to 11-year-olds — all sedentary when the study started — gives educators the evidence they need to ensure that regular, vigorous physical activity is a part of every school day, said Dr. Catherine Davis, clinical health psychologist at GHSU’s Georgia Prevention Institute and corresponding author on the study in Health Psychology.

“I hope these findings will help reestablish physical activity’s important place in the schools in helping kids stay physically well and mentally sharp,” Davis said. “For children to reach their potential, they need to be active.”

To measure cognition, researchers used the Cognitive Assessment System and Woodcock-Johnson Tests of Achievement III that measure abilities such as planning and academic skills such as math and reading. A subset of the children received functional magnetic resonance imaging highlighting increased or decreased areas of brain activity.

MRIs showed those who exercised experienced increased brain activity in the prefrontal cortex — an area associated with complex thinking, decision making and correct social behavior — and decreased activity in an area of the brain that sits behind it. The shift forward appears consistent with more rapidly developing cognitive skills, Davis said.

And the more they exercised, the better the result. Intelligence scores increased an average 3.8 points in those exercising 40 minutes per day after school for three months with a smaller benefit in those exercising 20 minutes daily.

Activity in the part of their brain responsible for so-called executive function also increased in children who exercised. “In kids you just don’t know what impact you are going to have when you improve their ability to control their attention, to behave better in school, to make better choices,” Davis notes. “Maybe they will be more likely to stay in school and out of trouble.”

Similar improvements were seen in math skills; interestingly, no improvements were found in reading skill. Researchers note that improved math achievement was “remarkable” since no math lessons were given and suggests longer intervention could produce even better results.

Children in the exercise program played hard, with running games, hula hoops and jump ropes, raising their heart rates to 79 percent of maximum, which is considered vigorous.

Cognitive improvements likely resulted from the brain stimulation that came from movement rather than resulting cardiovascular improvements, such as increased blood and oxygen supplies, Davis said. “You cannot move your body without your brain.”

The researchers hypothesize that such vigorous physical activity promotes development of brain systems that underlie cognition and behavior. Animal studies have shown that aerobic activity increases growth factors so the brain gets more blood vessels, more neurons and more connections between neurons. Studies in older adults have shown exercise benefits the brain and Davis’s study extends the science to children and their ability to learn in school.

About one-third of U.S. children are overweight. Davis suspects exercise would have a similar impact on their leaner counterparts.

Co-authors include Dr. Jennifer E. McDowell, neuroscientist, and Dr. Phillip Dr. Tomporowski, exercise and cognition expert, at the University of Georgia.

Email or share this story:

Story Source:

The above story is reprinted (with editorial adaptations by newsPsychology staff) from materials provided by Medical College of Georgia. The original article was written by Toni Baker.

Journal Reference:

1. By Davis, Catherine L.; Tomporowski, Phillip D.; McDowell, Jennifer E.; Austin, Benjamin P.; Miller, Patricia H.; Yanasak, Nathan E.; Allison, Jerry D.; Naglieri, Jack A. Exercise improves executive function and achievement and alters brain activation in overweight children: A randomized, controlled trial.. Health Psychology, Vol 30(1), Jan 2011, 91-98 [link]

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of NewsPsychology or its staff.

NewsPsychology (Feb. 10, 2011) — When the EPA phased out the widespread residential use of chlorpyrifos and other organophosphorus (OP) insecticides in 2000-2001 because of risks to child neurodevelopment, these compounds were largely replaced with pyrethroid insecticides. But the safety of these replacement insecticides remained unclear, as they had never been evaluated for long-term neurotoxic effects after low-level exposure. In the first study to examine the effects of these compounds on humans and the first evaluation of their potential toxicity to the developing fetal brain, scientists of the Columbia Center for Children’s Environmental Health at Columbia University’s Mailman School of Public Health found a significant association between piperonyl butoxide (PBO), a common additive in pyrethroid formulations, measured in personal air collected during the third trimester of pregnancy, and delayed mental development at 36 months.

Findings from the study are online in the journal, Pediatrics.

The study was conducted with a subset of 725 pregnant women participating in a prospective longitudinal study of black and Dominican women living in upper Manhattan and the South Bronx underway at the Columbia Center for Children’s Environmental Health (CCCEH). The insecticide permethrin was selected for the evaluation because it is one of the most common pyrethroid insecticides used in U.S. homes, as well as the most commonly sold pesticide, according to a nationally representative sample. PBO, a chemical that is added to insecticides to increase efficacy was also selected for evaluation. Any detection of PBO in air is a marker of a pyrethroid insecticide application.

In all, 342 women were studied for permethrin exposure in personal air during pregnancy; 272 for permethrin in maternal and umbilical cord plasma; and 230 were evaluated for exposure to PBO. To collect the air samples, mothers from the CCCEH Mothers and Newborns cohort wore a small backpack holding a personal ambient air monitor for 48 hours during the third trimester of pregnancy.

The children of these mothers were evaluated for cognitive and motor development at age three. CCCEH researchers used the Bayley Scales of Infant Development. In evaluating the results, researchers controlled for gender, gestational age, ethnicity, maternal education and intelligence, quality of the home environment, and prenatal exposure to environmental tobacco smoke and chlorpyrifos.

PBO was detected in the majority of personal air samples (75%). While the results demonstrate that a significant prenatal exposure to permethrin in personal air and/or plasma was not associated with performance scores for the Bayley Mental Developmental Index or the Psychomotor Developmental Index at 36 months, children who were more highly exposed to PBO in personal air samples (≥4.34 ng/m3) scored 3.9 points lower on the Mental Developmental Index than those with lower exposures.

“This drop in IQ points is similar to that observed in response to lead exposure,” said Megan Horton of the Mailman School of Public Health and lead researcher. “While perhaps not impacting an individual’s overall function, it is educationally meaningful and could shift the distribution of children in the society who would be in need of early intervention services.”

The researchers point out that environmental and biological monitoring of pyrethroid insecticides present certain challenges. “We know most pyrethroid insecticides are difficult to measure in the air because they are not volatile and are difficult to measure in bodily fluids because they are rapidly metabolized, and these difficulties may prevent us from seeing significant associations with neurodevelopmental outcomes,” noted Dr. Horton. “Because PBO is volatile and permethrin is not volatile, we would not expect to find a strong association between the two compounds. With the exception of the increased odds of motor delay in the lowest PBO exposure group, prenatal exposure to PBO seems to have an impact on cognitive rather than motor development, which is quite worrisome because mental development scores are more predictive of school readiness.”

As this is the first study of these compounds, the results should be considered preliminary but, Dr. Horton notes, they do — raise a cautionary red flag about the use of these chemicals during pregnancy. And, she adds, research at the Columbia Center for Children’s Environmental Health, indicates that “integrated pest management and the non-spray application of lower toxicity pesticides are viable alternatives to the use of these spray pesticides for pest control.”

“This is an important study with potentially broad public health implications,” according to Dr. Robin Whyatt, Mailman School professor of clinical environmental health sciences and a co-deputy director at the CCCEH. “Further, it identifies a critical need for additional research.”

Email or share this story:

Story Source:

The above story is reprinted (with editorial adaptations by newsPsychology staff) from materials provided by Columbia University’s Mailman School of Public Health, via EurekAlert!, a service of AAAS.

Journal Reference:

1. M. K. Horton, A. Rundle, D. E. Camann, D. B. Barr, V. A. Rauh, R. M. Whyatt. Impact of Prenatal Exposure to Piperonyl Butoxide and Permethrin on 36-Month Neurodevelopment. Pediatrics, 2011; DOI: 10.1542/peds.2010-0133

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of NewsPsychology or its staff.

The human brain operates as a highly interconnected small-world network, not as a collection of discrete regions as previously believed, with important implications for why many of us experience cognitive declines in old age, a new study shows.

Australian researchers have mapped the brain's neural networks and for the first time linked them with specific cognitive functions, such as information processing and language. Results from the study are published in the Journal of Neuroscience.

The researchers from the University of New South Wales are now examining what factors may influence the efficiency of these networks in the hope they can be manipulated to reduce age-related decline.

"While particular brain regions are important for specific functions, the capacity of information flow within and between regions is also crucial," said study leader Scientia Professor Perminder Sachdev from UNSW's School of Psychiatry.

"We all know what happens when road or phone networks get clogged or interrupted. It's much the same in the brain.

"With age, the brain network deteriorates and this leads to slowing of the speed of information processing, which has the potential to impact on other cognitive functions."

The advent of new MRI technology and increased computational power had allowed the development of the neural maps, resulting in a paradigm shift in the way scientists view the brain, Professor Sachdev said.

"In the past when people looked at the brain they focused on the grey matter in specific regions because they thought that was where the activity was. White matter was the poor cousin. But white matter is what connects one brain region to another and without the connections grey matter is useless," he said.

In the study, the researchers performed magnetic resonance imaging (MRI) scans on 342 healthy individuals aged 72 to 92, using a new imaging technique called diffusion tensor imaging (DTI).

Using a mathematical technique called graph theory, they plotted and measured the properties of the neural connectivity they observed.

"We found that the efficiency of the whole brain network of cortical fibre connections had an influence on processing speed, visuospatial function — the ability to navigate in space — and executive function," said study first author Dr Wei Wen.

"In particular greater processing speed was significantly correlated with better connectivity of nearly all the cortical regions of the brain."

Professor Sachdev said the findings help explain how cognitive functions are organised in the brain, and the more highly distributed nature of some functions over others.

"We are now examining the factors that affect age-related changes in brain network efficiency — whether they are genetic or environmental — with the hope that we can influence them to reduce age-related decline," Professor Sachdev said.

"We know the brain is not immutable; that if we work on the plasticity in these networks we may be able to improve the efficiency of the connections and therefore cognitive functions.".

Journal Reference:

1. W. Wen, W. Zhu, Y. He, N. A. Kochan, S. Reppermund, M. J. Slavin, H. Brodaty, J. Crawford, A. Xia, P. Sachdev. Discrete Neuroanatomical Networks Are Associated with Specific Cognitive Abilities in Old Age. Journal of Neuroscience, 2011; 31 (4): 1204 DOI: 10.1523/JNEUROSCI.4085-10.2011

NewsPsychology (Feb. 3, 2011) — Are we on the verge of being able to stimulate the brain to see the world anew — an electric thinking cap? Research by Richard Chi and Allan Snyder from the Centre for the Mind at the University of Sydney suggests that this could be the case.

They found that participants who received electrical stimulation of the anterior temporal lobes were three times as likely to reach the fresh insight necessary to solve a difficult, unfamiliar problem than those in the control group. The study published on February 2 in the open-access journal PLoS ONE.

According to the authors, our propensity to rigidly apply strategies and insights that have had previous success is a major bottleneck to making creative leaps in solving new problems. There is normally a cognitive tradeoff between the necessity of being fast at the familiar on one hand and being receptive to novelty on the other.

Chi and Snyder argue that we can modulate this tradeoff to our advantage by applying transcranial direct current stimulation (tDCS), a safe, non-invasive technique that temporarily increases or decreases excitability of populations of neurons. In particular, tDCS can be used to manipulate the competition between the left and right hemisphere by inhibiting and/or disinhibiting certain networks. Their findings are consistent with evidence that the right anterior temporal lobe is associated with insight or novel meaning and that inhibition of the left anterior temporal lobe can induce a cognitive style that is less top-down, less influenced by preconceptions.

While further studies involving brain stimulation in combination with neuroimaging are needed to elucidate the exact mechanisms leading to insight, Chi and Snyder can imagine a future when non-invasive brain stimulation is briefly employed for solving problems that have evaded traditional cognitive approaches.

Journal Reference:

1. Richard P. Chi, Allan W. Snyder. Facilitate Insight by Non-Invasive Brain Stimulation. PLoS ONE, 2011; 6 (2): e16655 DOI: 10.1371/journal.pone.0016655