The small grooves on the surface of our brain may play a key role in our reasoning. A recent study reveals that their depth influences connectivity between areas essential for cognition.
Long considered mere byproducts of evolution, these structures, called tertiary sulci, are now attracting neuroscientists' interest. Their individual variations appear linked to differences in intellectual performance, opening avenues for understanding neurodevelopmental disorders.
Sulci that shape our brain connections
Researchers at the University of California, Berkeley analyzed the brains of 43 children and adolescents. Their work, published in
The Journal of Neuroscience, shows that deeper sulci strengthen exchanges between the lateral prefrontal cortex and lateral parietal cortex. These regions are involved in complex cognitive functions.
The proposed hypothesis suggests these folds physically bring brain areas closer together, optimizing neural communication. This configuration would partly explain why some individuals exhibit better reasoning abilities. Tertiary sulci, which appeared late in evolution, may thus serve as anatomical markers of our skills.
Scientists used functional MRI to map brain activity during logic tasks. Results indicate each sulcus has a unique connectivity signature, identifiable with 96% accuracy. This specificity confirms their functional role beyond mere structure.
Plasticity influenced by environment
Contrary to popular belief, these brain structures aren't immutable. Their morphology evolves throughout life in response to learning and environment. This discovery offers promising perspectives: intellectual stimulation could influence sulci development, and thus our cognitive abilities.
However, the study reveals not all cortical folds react similarly. Only particular sulci in key reasoning areas show clear correlation with intellectual performance. Their precise identification could eventually serve as an indicator for assessing brain development.
Researchers emphasize education's key role in this process. Even in adulthood, the brain retains some malleability. This work confirms the importance of early stimulation while offering new avenues for understanding learning disorders.
This plasticity also raises questions: to what extent can we "sculpt" our brain through cognitive training? Scientists are now exploring this path, while noting sulci are just one piece in the intelligence puzzle.
Article author: Cédric DEPOND