Link Found Between Brain Metabolism and Fluid Intelligence

By measuring a metabolic activity marker using magnetic resonance spectroscopy (MRS), a new study in young adults has indicated that healthy brain metabolism corresponds with fluid intelligence, a measure of one’s ability to solve unusual or complex problems.

“Fluid intelligence is one of the most useful cognitive measures available. This domain relates to an individual’s job satisfaction and salary level, among other real-world outcomes,” said Aki Nikolaidis, PhD student who led the research at University of Illinois at Urbana-Champaign (Champaign, IL, USA) with Ryan Larsen, research scientist at UI’s Beckman Institute for Advanced Science & Technology (Urbana, IL, USA) and Beckman Institute director Arthur Kramer.

The researchers used MRS to measure concentrations of N-acetyl aspartate (NAA), a known marker of metabolic activity in the brain. They then examined the relationship between fluid intelligence and NAA concentrations in different regions of the brain. “MRS allows us to go beyond simply imaging the structures of the brain. It allows us to image the capacity of the brain to produce energy,” said Prof. Larsen.

Previous research relating MRS data to cognition has been inconsistent. One explanation may be that researchers did not account for all relevant factors that relate to cognition, including brain size, in their analyses. One goal of the current study was to address these previous contradictions. “We wanted to do a more definitive study with a large sample size and with a higher quality methodological approach of acquiring the data,” said Nikolaidis.

The researchers were able to create a more detailed map of brain NAA concentration than previous studies. This enabled them to find that NAA concentration in a brain area linked to motor abilities in the frontal and parietal cortices was specifically linked to fluid intelligence, but not to other closely related cognitive abilities. The brain’s motor regions have a role in planning and visualizing movements as well as in carrying them out. Mental visualization is a key element of fluid intelligence.

The researchers found a biochemical link showing that fluid intelligence depends on healthy brain metabolism. While overall brain size is genetically determined and not readily changed, brain metabolism (e.g., NAA levels) may respond to health interventions, including diet, exercise, or cognitive training.

The paper, by Nikolaidis A et al, was published online ahead of print March 22, 2016, in the journal Cerebral Cortex.

Related Links:
University of Illinois at Urbana-Champaign 
Beckman Institute for Advanced Science and Technology