Parietal Lobe
Older news items (pre-2010) brought over from the old website
September 2009
Tetris increases gray matter and improves brain efficiency
In a study in which 26 adolescent girls played the computer game Tetris for half an hour every day for three months, their brains compared to controls increased grey matter in Brodmann Area 6 in the left frontal lobe and BAs 22 and 38 in the left temporal lobe — areas involved in planning complex coordinated movements, and coordinating sensory information. Their brains also showed greater efficiency, but in different areas — ones associated with critical thinking, reasoning, and language, mostly in the right frontal and parietal lobes. The finding points to improved efficiency being unrelated to grey matter increases.
Haier, R.J. et al. 2009. MRI assessment of cortical thickness and functional activity changes in adolescent girls following three months of practice on a visual-spatial task. BMC Research Notes, 2, 174.
http://www.eurekalert.org/pub_releases/2009-09/bc-itg090109.php
Neural changes produced by learning to read revealed
Understanding how our brain structures change as we learn to read is difficult because of the confounding with age and the learning of other skills. Studying adult learners is also problematic because in most educated societies adult illiteracy is typically the result of learning impairments or poor health. Now a new study involving 20 former guerrillas in Colombia who are learning to read for the first time as adults has found that these late-literates showed a number of significant brain differences compared to matched adult illiterates, including more white matter between various regions, and more grey matter in various left temporal and occipital regions important for recognizing letter shapes and translating letters into speech sounds and their meanings. Particularly important were connections between the left and right angular gyri in the parietal lobe. While this area has long been known as important for reading, its function turns out to have been misinterpreted — it now appears its main role is in anticipating what we will see. The findings will help in understanding the causes of dyslexia.
Carreiras, M. et al. 2009. An anatomical signature for literacy. Nature, 461 (7266), 983-986.
http://www.physorg.com/news174744233.html
December 2008
Sex difference on spatial skill test linked to brain structure
It’s been well established that men (as a group) consistently out-perform women on spatial tasks. Research has also established that the parietal lobes in women tend to have proportionally more gray matter. Now a new study shows that the thicker cortex in the parietal lobe in women is associated with poorer mental rotation ability. It also reveals that the surface area of the parietal lobe is increased in men, compared to women, and this is directly related to better performance on mental rotation tasks. It also appears that, perhaps because the brain structure is different between men and women, the way the brain performs the task is different. While men appear able to globally rotate an object in space, women seem to do it piecemeal.
Koscik, T. et al. 2008. Sex differences in parietal lobe morphology: Relationship to mental rotation performance. Brain and Cognition, Article in Press
http://www.physorg.com/news148740976.html
March 2007
Disentangling attention
A new study provides more evidence that the ability to deliberately focus your attention is physically separate in the brain from the part that helps you filter out distraction. The study trained monkeys to take attention tests on a video screen in return for a treat of apple juice. When the monkeys voluntarily concentrated (‘top-down’ attention), the prefrontal cortex was active, but when something distracting grabbed their attention (‘bottom-up’ attention), the parietal cortex became active. The electrical activity in these two areas vibrated in synchrony as they signaled each other, but top-down attention involved synchrony that was stronger in the lower-frequencies and bottom-up attention involved higher frequencies. These findings may help us develop treatments for attention disorders.
Buschman, T.J. & Miller, E.K. 2007. Top-Down Versus Bottom-Up Control of Attention in the Prefrontal and Posterior Parietal Cortices. Science, 315 (5820), 1860-1862.
Right parietal lobe implicated in dyscalculia
By temporarily knocking out an area in the right parietal lobe (the right intraparietal sulcus), researchers have induced dyscalculia in normal subjects, providing strong evidence that dyscalculia is caused by malfunction in this area. These findings were further validated by testing participants suffering from developmental dyscalculia. Although less well-known, dyscalculia is as prevalent as dyslexia and attention deficit hyperactivity disorder (around 5%).
Kadosh, R.C. et al. 2007. Virtual Dyscalculia Induced by Parietal-Lobe TMS Impairs Automatic Magnitude Processing. Current Biology, online ahead of print March 22
http://www.sciencedaily.com/releases/2007/03/070322132931.htm
http://www.eurekalert.org/pub_releases/2007-03/ucl-tro032107.php
April 2006
Fast language learners have more white matter in auditory region
An imaging study has found that fast language learners have more white matter in a region of the brain that’s critical for processing sound. The study involved 65 French adults in their twenties, who were asked to distinguish two closely related sounds (the French 'da' sound from the Hindi 'da' sound). There was considerable variation in people’s ability to learn to tell these sounds apart — the fastest could do it within 8 minutes; the slowest were still guessing randomly after 20 minutes. The 11 fastest and 10 slowest learners were then given brain scans, revealing that the fastest learners had, on average, 70% more white matter in the left Heschl's gyrus than the slowest learners, as well as a greater asymmetry in the parietal lobe (the left being bigger than the right).
Golestani, N., Molko, N., Dehaene, S., LeBihan, D. & Pallier, C. 2006. Brain Structure Predicts the Learning of Foreign Speech Sounds. Cerebral Cortex, Advance Access published on April 7, 2006
http://www.newscientist.com/article.ns?id=dn8964&print=true
June 2005
How sleep improves memory
While previous research has been conflicting, it does now seem clear that sleep consolidates learning of motor skills in particular. A new imaging study involving 12 young adults taught a sequence of skilled finger movements has found a dramatic shift in activity pattern when doing the task in those who were allowed to sleep during the 12 hour period before testing. Increased activity was found in the right primary motor cortex, medial prefrontal lobe, hippocampus and left cerebellum — this is assumed to support faster and more accurate motor output. Decreased activity was found in the parietal cortices, the left insular cortex, temporal pole and fronto-polar region — these are assumed to reflect less anxiety and a reduced need for conscious spatial monitoring. It’s suggested that this is one reason why infants need so much sleep — motor skill learning is a high priority at this age. The findings may also have implications for stroke patients and others who have suffered brain injuries.
Walker, M.P., Stickgold, R., Alsop, D., Gaab, N. & Schlaug, G. 2005. Sleep-dependent motor memory plasticity in the human brain.Neuroscience, 133 (4) , 911-917.
http://www.eurekalert.org/pub_releases/2005-06/bidm-ssh062805.php
January 2005
IQ-related brain areas may differ in men and women
An imaging study of 48 men and women between 18 and 84 years old found that, although men and women performed equally on the IQ tests, the brain structures involved in intelligence appeared distinct. Compared with women, men had more than six times the amount of intelligence-related gray matter, while women had about nine times more white matter involved in intelligence than men did. Women also had a large proportion of their IQ-related brain matter (86% of white and 84% of gray) concentrated in the frontal lobes, while men had 90% of their IQ-related gray matter distributed equally between the frontal lobes and the parietal lobes, and 82% of their IQ-related white matter in the temporal lobes. The implications of all this are not clear, but it is worth noting that the volume of gray matter can increase with learning, and is thus a product of environment as well as genes. The findings also demonstrate that no single neuroanatomical structure determines general intelligence and that different types of brain designs are capable of producing equivalent intellectual performance.
Haier, R.J., Jung, R.E., Yeo, R.A., Head, K. & Alkire, M.T. 2005. The neuroanatomy of general intelligence: sex matters. NeuroImage, In Press, Corrected Proof, Available online 16 January 2005
http://www.eurekalert.org/pub_releases/2005-01/uoc--iim012005.php
http://www.sciencedaily.com/releases/2005/01/050121100142.htm
October 2004
Development of working memory with age
An imaging study of 20 healthy 8- to 30-year-olds has shed new light on the development of working memory. The study found that pre-adolescent children relied most heavily on the prefrontal cortex and parietal regions of the brain during the working memory task; adolescents used those regions plus the anterior cingulate; and in adults, a third area of the brain, the medial temporal lobe, was brought in to support the functions of the other areas. Adults performed best. The results support the view that a person's ability to have voluntary control over behavior improves with age because with development, additional brain processes are used.
http://www.eurekalert.org/pub_releases/2004-10/uopm-dow102104.php
July 2004
Intelligence based on the volume of gray matter in certain brain regions
Confirming earlier suggestions, the most comprehensive structural brain-scan study of intelligence to date supports an association between general intelligence and the volume of gray matter tissue in certain regions of the brain. Because these regions are located throughout the brain, a single "intelligence center" is unlikely. It is likely that a person's mental strengths and weaknesses depend in large part on the individual pattern of gray matter across his or her brain. Although gray matter amounts are vital to intelligence levels, only about 6% of the brain’s gray matter appears related to IQ — intelligence seems related to an efficient use of relatively few structures. The structures that are important for intelligence are the same ones implicated in memory, attention and language. There are also age differences: in middle age, more of the frontal and parietal lobes are related to IQ; less frontal and more temporal areas are related to IQ in the younger adults. Previous research has shown the regional distribution of gray matter in humans is highly heritable. The findings also challenge the recent view that intelligence may be a reflection of more subtle characteristics of the brain, such as the speed at which nerve impulses travel in the brain, or the number of neuronal connections present. It may of course be that all of these are factors.
Haier, R.J., Jung, R.E., Yeo, R.A., Head, K. & Alkire, M.T. 2004. Structural brain variation and general intelligence. Neuroimage. In press. http://dx.doi.org/10.1016/j.neuroimage.2004.04.025
http://www.sciencedaily.com/releases/2004/07/040720090419.htm
http://www.eurekalert.org/pub_releases/2004-07/uoc--hid071904.php
November 2003
Maturation of the human brain mapped
The progressive maturation of the human brain in childhood and adolescence has now been mapped. The initial overproduction of synapses in the gray matter that occurs after birth, is followed, for the most part just before puberty, with their systematic pruning. The mapping has confirmed that this maturation process occurs in different regions at different times, and has found that the normal gray matter loss begins first in the motor and sensory parts of the brain, and then slowly spreads downwards and forwards, to areas involved in spatial orientation, speech and language development, and attention (upper and lower parietal lobes), then to the areas involved in executive functioning, attention or motor coordination (frontal lobes), and finally to the areas that integrate these functions (temporal lobe). "The surprising thing is that the sequence in which the cortex matures appears to agree with regionally relevant milestones in cognitive development, and also reflects the evolutionary sequence in which brain regions were formed."
http://www.eurekalert.org/pub_releases/2003-11/sfn-smm110803.php
November 2001
Differential effects of encoding strategy on brain activity patterns
Encoding and recognition of unfamiliar faces in young adults were examined using PET imaging to determine whether different encoding strategies would lead to differences in brain activity. It was found that encoding activated a primarily ventral system including bilateral temporal and fusiform regions and left prefrontal cortices, whereas recognition activated a primarily dorsal set of regions including right prefrontal and parietal areas. The type of encoding strategy produced different brain activity patterns. There was no effect of encoding strategy on brain activity during recognition. The left inferior prefrontal cortex was engaged during encoding regardless of strategy.
Bernstein, L.J., Beig, S., Siegenthaler, A.L. & Grady, C.L. 2002. The effect of encoding strategy on the neural correlates of memory for faces. Neuropsychologia, 40 (1), 86 - 98.