Brain Grooves & Reasoning: Deeper is Better
- The depth of small grooves on the brain's surface is linked to stronger network connectivity and better reasoning ability, a new study reveals.
- However, neuroscientists are discovering these folds are more than just artifacts.
- Researchers suggest the grooves may bring brain areas closer, shortening connections and speeding communication.
Uncover a groundbreaking link: Researchers have confirmed a connection between brain groove depth and reasoning ability—the primarykeyword of this study. The findings, published by UC Berkeley, suggest that deeper grooves correlate with stronger network connectivity, potentially offering diagnostic uses for neurodevelopmental disorders. Analyzing the variability of tertiary sulci could help explain individual cognitive differences. This research, brought to you by News Directory 3, could also lead to biomarkers for reasoning ability and enhanced understanding of the human brain. Learn how the secondarykeyword, brain structure, impacts cognitive function. Discover what’s next in the quest for personalized interventions and improved reasoning skills.
Brain Grooves Linked to Reasoning ability, Study Finds
Updated May 31, 2025
The depth of small grooves on the brain’s surface is linked to stronger network connectivity and better reasoning ability, a new study reveals. While many grooves and dimples are unique to humans, they’re often dismissed as a byproduct of a large brain squeezed into a small skull.
However, neuroscientists are discovering these folds are more than just artifacts. According to research from the university of California, Berkeley, the depths of the smallest grooves, known as tertiary sulci, correlate with increased connectivity between brain regions involved in high-level cognitive functions. The findings appeared in The Journal of Neuroscience.
Researchers suggest the grooves may bring brain areas closer, shortening connections and speeding communication. This variability in tertiary sulci could explain individual differences in cognitive performance and potentially serve as diagnostic indicators for reasoning ability or neurodevelopmental disorders.
“The impetus for this study was having seen that sulcal depth correlated with reasoning across children and adolescents,” said Silvia Bunge, professor of psychology at UC Berkeley’s Helen Wills Neuroscience Institute (HWNI).
kevin Weiner, UC Berkeley associate professor of psychology and neuroscience, added that the hypothesis is that the formation of sulci leads to shortened distances between connected brain regions, potentially increasing neural efficiency and improving cognition.
hills and Valleys
Most animal brains have smooth surfaces, but primates have hills and valleys covering their cerebral cortex.Human brains feature deeply incised sulci, with 60% to 70% of the cortex buried within these folds.These cortical folding patterns change with age, solidifying in late prenatal progress and becoming less prominent in old age.
Bunge noted that while sulci can change over time, an individual’s configuration of sulci remains a stable difference. Scientists believe tertiary sulci, unique to humans, emerge in brain regions that have expanded the most throughout evolution and are associated with reasoning, decision-making, planning, and self-control.
Prior to this study,evidence linking tertiary sulci and brain connectivity was scarce. The UC Berkeley study provides proof of this connection.
Sulci and Cognition
Weiner and Bunge noted the lack of emphasis on tertiary sulci in their undergraduate education, often examining scans of average brains that didn’t match specific individuals.
Weiner’s earlier work showed that the mid-fusiform sulcus varied substantially in length among individuals, and the longer the sulcus, the better a person was at recognizing faces. He and Bunge then investigated whether tertiary sulci in other brain regions also correlated with cognitive ability.
Their 2021 paper defined the smaller sulci in the lateral prefrontal cortex and created a computer model identifying tertiary sulci as contributing the most variation in reasoning ability.
Expanding on that work, the new study cataloged tertiary sulci in the lateral parietal cortex and investigated its functional connections with the sulci of the lateral prefrontal cortex. Researchers studied 43 participants, ages 7 to 18, using functional magnetic resonance imaging (fMRI) while they performed a reasoning task. They focused on brain activity in 21 sulci in each hemisphere and the functional connections between them.
Greater depth in several sulci implicated in reasoning was associated with higher network centrality across the set of prefrontal and parietal sulci.
Experience Affects Sulci
Bunge emphasized that the association between sulci depths and reasoning does not apply to all sulci and that sulcal depth may change with experience. Cognitive function depends on various anatomical and functional features, and experience, such as quality of schooling, plays a powerful role in shaping an individual’s cognitive trajectory.
Weiner’s lab is developing a computer program to help researchers identify tertiary sulci in the human brain. Current programs identify about 35 sulci,but including tertiary sulci increases the number to over 100. They suggest sulci could serve as landmarks for comparing brains between individuals.
“Examining network architecture based on individual sulcal morphology circumvents these disagreements and mismatches, with the prospect to glean network-level insight from the local sulcal anatomy that is specific to a given individual,” Weiner said.
What’s next
Researchers plan to continue investigating the relationship between brain structure and cognitive function, with the goal of developing more precise diagnostic tools for neurodevelopmental disorders and personalized interventions to improve reasoning skills.