New research shows how brain wrinkles might influence brain function

MRI of the rhesus macaque brain at mid gestation (left), prior to folding and two-thirds through gestation (middle) as folds are forming. Color indicates (right) the angle between the cortical surface and the direction of neighboring fibers within the developing white matter.

New research clarifies how the brain’s telltale wrinkles and folds develop as a result of mechanical feedback as the brain develops before birth.

The study suggests that alterations from the typical pattern of brain shape at maturity, associated with neurodevelopmental and psychiatric disorders, could be rooted in development of the brain’s cortex as opposed to differences driven by development of white matter. These findings were made through a collaboration between scientists at OHSU and Indiana University.

Authors concluded that expansion and folding of the brain’s cortex contributes to the growth and organization of white matter – not the other way around.

The study, published in the journal Nature Communications, involved computer simulations that explicitly incorporated tension-induced axon elongation, which is a well-known biological phenomenon. The simulations predicted a typified organization of white matter in relation to cortical folds, and the existence of this pattern was experimentally confirmed with magnetic resonance imaging results obtained from developing rhesus macaque brains.

The findings may be useful as researchers discern differences detected in brain imaging among people with developmental or psychiatric conditions, said co-author Chris Kroenke, Ph.D., professor in the Division of Neuroscience at the Oregon National Primate Research Center at OHSU.

Kroenke and collaborators Kara Garcia, Ph.D., researcher at Indiana University, and Xiaojie Wang, Ph.D., with the Advanced Imaging Research Center and primate research center at OHSU, concluded that expansion and folding of the brain’s cortex contributes to the growth and organization of white matter – not the other way around.

“These findings add to basic scientific understanding about why brains adopt the shapes they do,” Kroenke said. “As associations between the cortical folding pattern and brain function becomes more robust, mechanistic studies become more critical for interpreting the developmental biological processes that are responsible for observed variations in brain structure.”

The work was supported by the National Institutes of Health, award numbers R01 NS111948 and R01 AA021981, and the National Science Foundation, award DMS-2011274.

Erik Robinson