Tuesday May 12 2009
CEA
Working under team coordinator Stanislas Dehaene at the joint Inserm/CEA NeuroSpin Cognitive neuroimaging unit, André Knops employed 3-Tesla magnetic resonance imaging (MRI) to record brain activity patterns in adults, either while they performed mental arithmetic (adding and subtracting) tasks or while they moved their eyes to the right or left of the screen. Signal processing software was used to identify the brain regions activated during the eye movements and deduce a brain activity-based algorithm unveiling a set of behavioural patterns in the subject group.
The researchers took the high-resolution MRI images obtained and were able to deduce – trial-by-trial – whether the person had looked right or looked left, with a 70% success rate. More surprising still was that this classification extended to the mental arithmetic task: they observed the same distinction between brain activities patterns during the left-right eye movements and during the adding/subtracting task – regardless of whether the calculations were performed with concrete object-sets (nonsymbolic calculation) or with symbolic numbers (symbolic calculation) presented as Arabic numerals.
They concluded that mental arithmetic resembled a kind of spatial displacement. To illustrate, it is true, to a point, that when a person who has learned to read from left to right calculates 18 + 5, their attention shifts ‘to the right’ from 18 to 23 in number space, as if the numbers were represented along a conceptual virtual line.
By highlighting the connection between number conception and spatial conception, these results shed light on how the brain organized arithmetic. These results also add support to Stanislas Dehaene’s hypothesis that school-learnt skills lead to a neuronal recycling of brain regions that we have inherited through evolution and that are dedicated to overlapping functions.
Looking at children with learning difficulties, games centred on matching numbers and space, such as Ludo, can often bring marked improvements in maths scores. Starting out from this principle, the team has developed an open-access interactive learning game called La course aux nombres (NumberRace) in order to facilitate the acquisition of arithmetic skills.
Brain map spotlighting the regions activated by mental arithmetic tasks (in yellow) and eye movement (choppy areas, in blue), and their crossover :
The brain area used to decode eye movement direction :
Reference
1 INSERM, Unité de neuroimagerie cognitive, Institut Fédératif de Recherche (IFR) 49,
Gif-sur-Yvette, France.
2 CEA/I2BM, Centre Neurospin, Gif-sur-Yvette, France
3 Université Paris-Sud, F-91405 Orsay, France
4 INRIA Saclay-Ile de France, Orsay, France
5 Collège de France, Paris, France
Mental arithmetic activates the cortical circuitry involved in spatial attention
CEA
Do our mathematic capacities hinge on the brain circuitry involved in spatial attention? This is one of the questions raised in a study led by a convergently-skilled team of CEA, Inserm, Inria and Paris-Sud University scientists headed under the NeuroSpin-based joint Inserm/CEA “Cognitive Neuroimaging” research unit.
Exploiting NeuroSpin’s 3-Tesla magnetic resonance neuroimaging facilities, the teams have highlighted unexpected links between number representations and spatial representations in the brain. Science Express has published this research, which could have important ramifications for how arithmetic is taught in schools.
Working under team coordinator Stanislas Dehaene at the joint Inserm/CEA NeuroSpin Cognitive neuroimaging unit, André Knops employed 3-Tesla magnetic resonance imaging (MRI) to record brain activity patterns in adults, either while they performed mental arithmetic (adding and subtracting) tasks or while they moved their eyes to the right or left of the screen. Signal processing software was used to identify the brain regions activated during the eye movements and deduce a brain activity-based algorithm unveiling a set of behavioural patterns in the subject group.
The researchers took the high-resolution MRI images obtained and were able to deduce – trial-by-trial – whether the person had looked right or looked left, with a 70% success rate. More surprising still was that this classification extended to the mental arithmetic task: they observed the same distinction between brain activities patterns during the left-right eye movements and during the adding/subtracting task – regardless of whether the calculations were performed with concrete object-sets (nonsymbolic calculation) or with symbolic numbers (symbolic calculation) presented as Arabic numerals.
They concluded that mental arithmetic resembled a kind of spatial displacement. To illustrate, it is true, to a point, that when a person who has learned to read from left to right calculates 18 + 5, their attention shifts ‘to the right’ from 18 to 23 in number space, as if the numbers were represented along a conceptual virtual line.
By highlighting the connection between number conception and spatial conception, these results shed light on how the brain organized arithmetic. These results also add support to Stanislas Dehaene’s hypothesis that school-learnt skills lead to a neuronal recycling of brain regions that we have inherited through evolution and that are dedicated to overlapping functions.
Looking at children with learning difficulties, games centred on matching numbers and space, such as Ludo, can often bring marked improvements in maths scores. Starting out from this principle, the team has developed an open-access interactive learning game called La course aux nombres (NumberRace) in order to facilitate the acquisition of arithmetic skills.
Brain map spotlighting the regions activated by mental arithmetic tasks (in yellow) and eye movement (choppy areas, in blue), and their crossover :
The brain area used to decode eye movement direction :
Reference
- « Recruitment of an area involved in eye movements during mental arithmetic », André Knops1, Bertrand Thirion2,4, Edward Hubbard1,2,3, Vincent Michel 2,3,4, Stanislas Dehaene 1,2,3,5
1 INSERM, Unité de neuroimagerie cognitive, Institut Fédératif de Recherche (IFR) 49,
Gif-sur-Yvette, France.
2 CEA/I2BM, Centre Neurospin, Gif-sur-Yvette, France
3 Université Paris-Sud, F-91405 Orsay, France
4 INRIA Saclay-Ile de France, Orsay, France
5 Collège de France, Paris, France
Read-around resources
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Our special report on “Medical imaging and brain research” with themed videoconferences featuring Stanislas Dehaene on “the road to decodifying the mechanisms of thought” and Denis Le Bihan on “a toolbox for exploring the brain”.
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“CEA-led research into the brain”, press pack (March 2009)
- The INSERM-CEA Cognitive Neuroimaging Unit website (in English), which also provides access to the NumberRace game software.