Introducing the brain: surface folding very important (Introduction)

by David Turell , Wednesday, May 21, 2025, 22:41 (10 hours, 11 minutes ago) @ David Turell

Not forced to fold, folds are very important:

https://medicalxpress.com/news/2025-05-groovy-brains-efficient.html

"Many grooves and dimples on the surface of the brain are unique to humans, but they're often dismissed as an uninteresting consequence of packing an unusually large brain into a too-small skull.

"But neuroscientists are finding that these folds are not mere artifacts, like the puffy folds you get when forcing a sleeping bag into a stuff sack. The depths of some of the smallest of these grooves seem to be linked to increased interconnectedness in the brain and better reasoning ability.

"In a study published in The Journal of Neuroscience, University of California, Berkeley researchers show that in children and adolescents, the depths of some small grooves are correlated with increased connectivity between regions of the brain—the lateral prefrontal cortex and lateral parietal cortex—involved in reasoning and other high-level cognitive functions.

"The grooves may actually bring those areas closer together in space, shortening the connections between them and speeding communications.

"The implication, the researchers say, is that variability in these small grooves, which are called tertiary sulci, may help explain individual differences in cognitive performance, and could serve as diagnostic indicators or biomarkers of reasoning ability or neurodevelopmental disorders.

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"'We had explicit predictions about which tertiary sulci in the lateral prefrontal cortex would be functionally connected to tertiary sulci in the lateral parietal cortex, and that panned out," added Kevin Weiner, UC Berkeley associate professor of psychology and of neuroscience and a member of HWNI. "Prefrontal and parietal cortices aside, the hypothesis is that the formation of sulci leads to shortened distances between connected brain regions, which could lead to increased neural efficiency, and then, in turn, individual differences in improved cognition with translational applications."

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"The brains of most animals, mammals included, have smooth surfaces. Primates have hills and valleys covering their cerebral cortex. While one group of primates, the New World monkeys called marmosets, have shallow, barely perceptible sulci, those of humans are deeply incised, with between 60% and 70% of the cortex buried in these folds.

"The cortical folding patterns in humans also change with age, establishing their final structure late in prenatal development while becoming less prominent in old age.

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"The smallest grooves, many of which are uniquely human, are called tertiary sulci because they appear last in prenatal development and are never as deep as the major or primary sulci that are most evident on the cerebral surface.

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"Across these individuals, greater depth for several of the sulci implicated in reasoning was associated with higher network centrality across the set of prefrontal and parietal sulci.

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"Do we think that an individual's capacity for reasoning is set in stone based on their cortical folding? No," she said. "Cognitive function depends on variability in a variety of anatomical and functional features, and importantly, we know that experience, like quality of schooling, plays a powerful role in shaping an individual's cognitive trajectory, and that it is malleable, even in adulthood."

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"'Dozens of brain maps have been proposed in just the last five years, but they disagree about the areas of associated regions in the cortex, and there are mismatches between areas at the group and individual level," Weiner said. "Examining network architecture based on individual sulcal morphology circumvents these disagreements and mismatches, with the opportunity to glean network-level insight from the local sulcal anatomy that is specific to a given individual.'"

Comment: That it is hard to map the brain with such individual variability to cover, is explained by the brain plasticity accommodating itself to the needs of each individual. Packing a brain into a small skull producing groves is empty thinking. Start with the premise based on design theory, everything is there for a reason.