General intelligence was found to depend on the quality of the connectivity of certain neural networks in the brain. In particular, general intelligence was associated with the functional organisation of the dorsal attention network (DAN) within the brain, found the researchers from the University of Urbana-Champaign, Illinois.
The study team assessed the quality of functional organisation of the DAN by analysing ‘small-world propensity’, a measure of how well the neural network is connected to locally clustered regions and globally integrated systems within the brain.
The scientists also found that a higher serum levels of MUFAs was correlated with higher small-world propensity in the DAN. Taking the two correlations together, they concluded that dietary MUFAs influence cognition via the DAN pathway.
"Our findings provide novel evidence that MUFAs are related to a very specific brain network, the dorsal attentional network, and how optimal this network is functionally organized," said study leader Professor Aron Barbey.
Previous research has suggested cognitive benefits of a MUFA-rich Mediterranean diet. However, this study is the first to identify the mechanism connecting nutritional status and functional network efficiency.
"Our results suggest that if we want to understand the relationship between MUFAs and general intelligence, we need to take the dorsal attention network into account. It's part of the underlying mechanism that contributes to their relationship," commented Barbey.
The team examined patterns of fatty acid types in blood samples from 99 healthy older adults and correlated these against functional MRI data measuring brain network connectivity and also with the results of a general intelligence test.
"In this study, we examined the relationship between groups of fatty acids and brain networks that underlie general intelligence. In doing so, we sought to understand if brain network organization mediated the relationship between fatty acids and general intelligence," said lead author Marta Zamroziewicz.
The researchers objective was to "Understand how nutrition might be used to support cognitive performance and to study the ways in which nutrition may influence the functional organization of the human brain," explained Barbey.
The findings pave the way for possible future intervention studies using MUFAs.
"This is important because if we want to develop nutritional interventions that are effective at enhancing cognitive performance, we need to understand the ways that these nutrients influence brain function."
"Our ability to relate those beneficial cognitive effects to specific properties of brain networks is exciting," Barbey said.
"This gives us evidence of the mechanisms by which nutrition affects intelligence and motivates promising new directions for future research in nutritional cognitive neuroscience," he concluded.
Volume 161 pp 241-250, doi: 10.1016/j.neuroimage.2017.08.043
“Nutritional status, brain network organization, and general intelligence”
Authors: Marta T. Zamroziewicz, M. Tanveer Talukdar, Chris E. Zwilling, Aron K. Barbey