Two studies in the January 18, 2007, issue of the journal Neuron, published by Cell Press, shed significant light on how the brain processes numerical information--both abstract quantities and their concrete representations as symbols. The researches said their findings will contribute to understanding how the brain processes quantitative information as well as lead to studies of how numerical representation in the brain develops in children. Such studies could aid in rehabilitating people who suffer from dyscalculia--an inability to understand, remember, and manipulate numbers. The researchers also said their findings offer insight into the mystery of how the brain learns to associate abstract symbols precisely with quantities.
Both studies reveal in unprecedented detail how structures in the parietal cortex--the region of higher cognitive processing just above the forehead--activates during perception of both abstract quantities and numerical symbols.
In one paper, Manuela Piazza and colleagues showed that regions of the parietal lobe activate in response to numbers, either when they are presented as patterns of dots or as Arabic numerals.
In their experiments, the researchers asked human volunteers to pay attention to the quantities conveyed by groups of dots or numeric digits presented to them. During the process, the subjects' brains were scanned using functional magnetic resonance imaging (fMRI), in which harmless magnetic fields and radio waves are used to measure blood flow in brain regions, which reflects activity.
The researchers found that the initial presentation of the numeric stimuli activated the parietal region of the subjects' brains, which subsided as they adapted to the stimulus. However, the activation rebounded when the subjects were presented with an abrupt change in the quantity, whether it was represented in the same (dots versus dots) or different (dots versus Arabic numerals) notation as the original. This Page: 1 2 3 4 Related biology news :1
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