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Neural Basis Of ‘Number Sense’ In Young Infants

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Behavioral experiments indicate that infants aged 4½ months or older possess an early “number sense” that allows them to detect changes in the number of objects.
Distinct cerebral pathways for object identity and number have been identified in the brain of human infants. (Credit: Izard V, Dehaene-Lambertz G, Dehaene S)

However, the neural basis of this ability was previously unknown.

In new research, Véronique Izard, Ghislaine Dehaene-Lambertz, and Stanislas Dehaene provide brain imaging evidence showing that very young infants are sensitive to both the number and identity of objects, and these pieces of information are processed by distinct neural pathways.

The authors recorded the electrical activity evoked by the brain on the surface of the scalp as 3-months-old infants were watching images of objects. The number or identity of objects occasionally changed.

The authors found that the infant brain responds to both changes, but in different brain regions, which map onto the same regions that activate in adults. These results show that very young infants are sensitive to small changes in number, and the brain organization that underlies the perception of object number and identity are established early during development.

PLoS Biology Vol. 6, No. 2, e11 doi:10.1371/journal.pbio.0060011

Distinct Cerebral Pathways for Object Identity and Number in Human Infants

Izard V, Dehaene-Lambertz G, Dehaene S 

All humans, regardless of their culture and education, possess an intuitive understanding of number. Behavioural evidence suggests that numerical competence may be present early on in infancy. Here, we present brain-imaging evidence for distinct cerebral coding of number and object identity in 3-mo-old infants. We compared the visual event-related potentials evoked by unforeseen changes either in the identity of objects forming a set, or in the cardinal of this set. In adults and 4-y-old children, number sense relies on a dorsal system of bilateral intraparietal areas, different from the ventral occipitotemporal system sensitive to object identity. Scalp voltage topographies and cortical source modelling revealed a similar distinction in 3-mo-olds, with changes in object identity activating ventral temporal areas, whereas changes in number involved an additional right parietoprefrontal network. These results underscore the developmental continuity of number sense by pointing to early functional biases in brain organization that may channel subsequent learning to restricted brain areas.

Written by huehueteotl

February 11, 2008 at 9:39 am

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