Brain regions involved in language: Research reports

language

April 2006

Specific brain region for reading

Although a number of imaging studies have provided support for the idea that there’s a specific area of the brain that enables us to read efficiently by allowing us to process the visual image of entire words, the question is still debated — partly because the same area also seems to be involved in the recognition of other objects and partly because damage in this region has never been confined to this region alone. Now the experience of an epileptic requiring removal of a small area next to the so-called visual word-form area (VWFA) in the left occipito-temporal cortex has provided evidence of the region's importance for reading. After the operation, the patient’s ability to comprehend words was dramatically slower, and the results were consistent with him reading letter by letter. A brain scan confirmed that the VWFA no longer lit up when words were read, perhaps because the surgery severed its connection to other parts of the brain.
The case study was reported in the 20 April issue of Neuron. Full reference
http://sciencenow.sciencemag.org/cgi/content/full/2006/419/2?etoc
http://www.sciam.com/article.cfm?chanID=sa003&articleID=000D3A4E-A8D1-1446-9A6283414B7F0000

May 2005

Brain region for understanding metaphors located

Four righthanded patients with damage to the left angular gyrus provide evidence that the angular gyrus is at least partly responsible for the human ability to understand metaphor. The angular gyrus is disproportionately larger in hominids than other primates, and is strategically located at the crossroads of areas specialized for processing touch, hearing and vision.
The paper was presented at the American Psychological Society annual convention in Los Angeles, May 26-29.
http://www.eurekalert.org/pub_releases/2005-05/uoc--gmu052005.htm

How the brain handles sarcasm

A study involving people with prefrontal-lobe damage, people with posterior-lobe damage and healthy controls, found that those with prefrontal damage were impaired in comprehending sarcasm, whereas the people in the other two groups had no such problem. Within the prefrontal group, people with damage in the right ventromedial area had the most trouble in comprehending sarcasm. The researchers suggest that the frontal lobes process the context, identifying the contradiction between the literal meaning and the social/emotional context, while the ventromedial prefrontal cortex integrates the literal meaning with the social/emotional knowledge of the situation and previous situations.
The findings appeared in the May issue of Neuropsychology. Full reference
Full text of the article is available at http://www.apa.org/journals/releases/neu193288.pdf
http://www.eurekalert.org/pub_releases/2005-05/apa-tao051705.htm

February 2005

Are language and math processed separately by the brain?

Challenging the view that mathematics and language use common cognitive resources, a recent study provides support for the view that the functions of math and language are separate in the human brain. The study involved three men with severe agrammatic aphasia, which means they're unable to understand or form sentences due to brain damage. They didn't understand a reversible sentence - for example, the difference between 'John kissed Kate' and 'Kate kissed John', but they were able to understand that 5 - 2 is different from 2 – 5 (but not when it was expressed in words: two minus five). The researcher takes the results as a demonstration that we can have cognition without language, however, because the men were all normal until they sustained brain damage, it doesn’t answer the question of whether sophisticated cognition could arise without language.
The research is published in the March 1 issue of the Proceedings of the National Academy of Sciences. Full reference
http://education.guardian.co.uk/egweekly/story/0,,1427167,00.html
http://news.bbc.co.uk/1/hi/sci/tech/4265763.stm
http://www.nature.com/news/2005/050214/full/050214-3.html

December 2004

Third language area in brain identified

Broca's and Wernicke's areas are two, connected, regions of the brain long known to be involved in language. Now, a new imaging study has identified a third area, dubbed Geschwind's territory. This area connects Broca's and Wernicke's areas via a region of the parietal lobe of the cortex, and may be important for the acquisition of language in childhood. The area is apparently the last area in the brain to mature, the completion of its maturation coinciding with the development of reading and writing skills.
The study was published online on 13 December in the Annals of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2004-12/jws-bir120704.htm

November 2001

Separate brain regions for living vs nonliving categories

Lobectomy patients were compared to normal control subjects on a variety of category naming and matching tasks. Patients were disproportionately impaired for naming living things relative to nonliving things. The authors argue that damage to the temporal lobe impairs lexical retrieval most strongly for living things and that the anterior temporal cortices are convergence zones particularly necessary for retrieving the names of living things.
The report appeared in the November issue of Brain and Language. Full reference

October 2001

Different brain regions implicated in the representation of the structure and meaning of pictured objects

Imaging studies continue apace! Having established that that part of the brain known as the fusiform gyrus is important in picture naming, a new study further refines our understanding by studying the cerebral blood flow (CBF) changes in response to a picture naming task that varied on two dimensions: familiarity (or difficulty: hard vs easy) and category (tools vs animals). Results show that although familiarity effects are present in the frontal and left lateral posterior temporal cortex, they are absent from the fusiform gyrus. The authors conclude that the fusiform gyrus processes information relating to an object's structure, rather than its meaning. The blood flows suggest that it is the left posterior middle temporal gyrus that is involved in representing the object's meaning.
The report appeared in Neuropsychologia. Full reference

mathematics

March 2007

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%).
The findings were published online ahead of print on March 22 in Current Biology. Full reference
http://www.sciencedaily.com/releases/2007/03/070322132931.htm
http://www.eurekalert.org/pub_releases/2007-03/ucl-tro032107.htm

March 2006

Scientists find brain function most important to math ability

A finding that an area of the brain widely thought to be involved in processing number information generally, in fact has two very separate functions, may be the key to diagnosing dyscalculia. One function is responsible for counting 'how many' things are present and the other is responsible for knowing 'how much'. The brain activity specific to estimating numbers of things is thought to be the brain network that underlies arithmetic and may be abnormal in dyscalculics.
The paper was published on March 21 in the Proceedings of the National Academy of Sciences. Full reference
http://www.eurekalert.org/pub_releases/2006-03/ucl-sfb030606.htm

February 2005

Are language and math processed separately by the brain?

Challenging the view that mathematics and language use common cognitive resources, a recent study provides support for the view that the functions of math and language are separate in the human brain. The study involved three men with severe agrammatic aphasia, which means they're unable to understand or form sentences due to brain damage. They didn't understand a reversible sentence - for example, the difference between 'John kissed Kate' and 'Kate kissed John', but they were able to understand that 5 - 2 is different from 2 – 5 (but not when it was expressed in words: two minus five). The researcher takes the results as a demonstration that we can have cognition without language, however, because the men were all normal until they sustained brain damage, it doesn’t answer the question of whether sophisticated cognition could arise without language.
The research is published in the March 1 issue of the Proceedings of the National Academy of Sciences. Full reference
http://education.guardian.co.uk/egweekly/story/0,,1427167,00.html
http://news.bbc.co.uk/1/hi/sci/tech/4265763.stm
http://www.nature.com/news/2005/050214/full/050214-3.html

music

February 2005

Where tunes get stuck in your head

An imaging study has added to our understanding of how tunes get “stuck” in our head. Participants in the study listened to familiar and unfamiliar pieces of music in which snippets of the music had been removed. Imaging revealed that, for familiar songs, brain activity continued in the auditory cortex during the silent gaps. Participants confirmed that during this time they continued to mentally “hear” the music. Different parts of the auditory cortex were active, depending on whether the section was purely instrumental, or had lyrics. Instrumental music seemed to require deeper searching, further back into the auditory processing stream, suggesting that lyrics (processed in more advanced parts of the processing stream) might be the focus of the memory. The findings support other recent research indicating that sensory-specific memories are stored in the brain regions that were involved in processing that information in the first place.
The report was published in the March 10 issue of Nature. Full reference
http://news.bbc.co.uk/1/hi/health/4332771.stm
http://www.eurekalert.org/pub_releases/2005-03/dc-drf030705.htm