turning on the brain

[Guest guest]

From Science Blog Jan 30 05

Thinking of prepositions turns brain 'on' in different ways

Parts of the human brain think about the same word differently, at least when it

comes to prepositions, according to new language research in stroke patients

conducted by scientists at Prude University and the University of Iowa. People

who speak English often use the same prepositions, words such as " on, " " in, "

" around " and " through, " to indicate time as well as location. For example,

compare " I will meet you 'at' the store, " to " I will meet you 'at' 3 p.m. " These

examples show how time may be thought of metaphorically in terms of space.

Just because it's the same word, however, doesn't mean the brain thinks about it

the same way, said Kemmerer, an assistant professor of psychological

sciences and linguistics at Purdue's College of Liberal Arts.

" There has been a lot of cognitive neuroscience research about how the brain

processes language pertaining to concrete things, such as animals or tools, "

said Kemmerer, who also is an adjunct faculty member at the University of Iowa's

Department of Neurology, where this research was conducted. " This is the first

cognitive neuroscience study to investigate brain regions for spatial and

temporal relations – those involving time – used in language.

" I was interested in whether these spatial or temporal prepositions can be

dissociated in individuals with brain damage. One might think that if a person's

knowledge of the word 'at' to describe location is impaired, then his or her

ability to use that same preposition to describe time would be disrupted. But we

found the words implying time are processed independently. "

This research was conducted at the Benton Neuropsychology Laboratory in Iowa's

Carver College of Medicine and was funded by the Purdue Research Foundation and

the National Institute for Neurological Disease and Stroke. Kemmerer's paper is

available online at Neuropsychologia.

" This study has potential implications for neurology, " Kemmerer said. " A

clinician could use information about how brain injuries in stroke patients

affect specific speech components to develop therapies to help their patients. "

The four patients in Kemmerer's study were used because of similar brain

injuries, such as lesions from stroke, in the perisylvian region, which is

responsible for language processing. Kemmerer found the stroke subjects who

passed the language tests asking about prepositions relevant to time

subsequently failed when these same words reflected spatial meanings. For

example, the subjects were asked to choose the correct preposition for scenarios

such as, " The baseball is 'on/in/against' the glove. " Two subjects did not

select " in " as the correct answer. However, they did select " in " as the correct

preposition for " It happened 'through/on/in' 1859. "

The other two subjects' test performances were the opposite.

Kemmerer's earlier research with Tranel, professor of neurology at Iowa's

Carver College of Medicine, had confirmed that the left inferior prefrontal and

left inferior parietal regions of the brain play a crucial role in processing

spatial prepositions. The previous research with Tranel was published in

October's Cognitive Neuropsychology.

This work, which has explored how different types of words are retrieved by

different parts of the brain, is part of a larger-scale investigation being

carried out by Tranel and his colleagues at the University of Iowa.

" For example, we have identified the anterior left temporal lobe as being

critical for proper nouns, whereas the left inferior prefrontal/premotor region

is important for verbs, " Tranel said. " The collaboration between myself, a

neuropsychologist, and professor Kemmerer, a neurolinguist, has yielded

important breakthroughs in understanding how the brain operates language, due to

the unique perspectives that these researchers bring to a common research

agenda. "

Three of the patients in Kemmerer's recent study also had damage to their

brains' left hemispheres, in an area known as the parietal lobe, which houses

the supramarginal gyrus. This area is involved in spatial meaning, and it is the

part of the brain that guides action. For example, the supramarginal gyrus

coordinates how a person moves his or her hand toward a glass of water. Previous

research with normal brains identifies this area as important also in the

knowledge and meaning of prepositions.

The patients with damage to the supramarginal gyrus did not score high on the

tasks that evaluated their knowledge of prepositions that dealt with space. In

comparison, the fourth patient, who did not have similar damage to this region

of the brain, was able to demonstrate complete knowledge of spatial

prepositions.

Kemmerer's next step will be looking at how the brain processes these

prepositions in other languages.

" If this is true in English, then what about the 6,000 other known languages in

the world? This time-and-space metaphor is used from language to language, but

how the metaphor is used does vary, " he said.

In English, months of the year are treated as containers. People say " in

January " or " in February. " Other languages treat months as surfaces. For

example, " on January " or " on February. " Despite the difference, there is a

metaphor at work, Kemmerer said.

" The cross-linguistic ubiquity of the metaphor suggests that people are

naturally inclined to conceptualize time in terms of space, " he said.

" Nevertheless, the neuropsychological data suggest that people don't need to

invoke the metaphor every time they use prepositions to talk about time. Just as

the word 'breakfast' doesn't require one to think of a morning meal in terms of

breaking a fast, so the sentence 'She arrived at 1:30' doesn't require one to

think of time as a series of points on a line. "

From Purdue University

----------

Internal Virus Database is out-of-date.

Checked by AVG Anti-Virus.

Version: 7.0.300 / Virus Database: 265.6.12 - Release Date: 01/14/2005