Double dissociation of structure-function relationships in memory and fluid intelligence observed with magnetic resonance elastography

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2018-05, Vol.171, p.99-106
• Main Authors: Johnson, Curtis L., Schwarb, Hillary, Horecka, Kevin M., McGarry, Matthew D.J., Hillman, Charles H., Kramer, Arthur F., Cohen, Neal J., Barbey, Aron K.
• Format: Article
• Language: English
• Subjects: Adult; Brain; Brain - diagnostic imaging; Brain - physiology; Brain mapping; Brain Mapping - methods; Cognition & reasoning; Cognitive ability; Elasticity Imaging Techniques - methods; Exercise; Female; Fitness training programs; Fluid intelligence; Hippocampus; Humans; Intelligence; Intelligence - physiology; Intelligence tests; Magnetic resonance elastography; Male; Mathematical problems; Mechanical properties; Memory; Memory - physiology; Mental task performance; Multiple sclerosis; Neuroimaging; Neurosciences; Orbitofrontal cortex; Physical fitness; Physiological psychology; Relational memory; Structure-function relationships; Success; Viscoelasticity; Young Adult; Young adults
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2018.01.007

Brain tissue mechanical properties, measured in vivo with magnetic resonance elastography (MRE), have proven to be sensitive metrics of neural tissue integrity. Recently, our group has reported on the positive relationship between viscoelasticity of the hippocampus and performance on a relational memory task in healthy young adults, which highlighted the potential of sensitive MRE measures for studying brain health and its relation to cognitive function; however, structure-function relationships outside of the hippocampus have not yet been explored. In this study, we examined the relationships between viscoelasticity of both the hippocampus and the orbitofrontal cortex and performance on behavioral assessments of relational memory and fluid intelligence. In a sample of healthy, young adults (N = 53), there was a significant, positive relationship between orbitofrontal cortex viscoelasticity and fluid intelligence performance (r = 0.42; p = .002). This finding is consistent with the previously reported relationship between hippocampal viscoelasticity and relational memory performance (r = 0.41; p = .002). Further, a significant double dissociation between the orbitofrontal-fluid intelligence relationship and the hippocampal-relational memory relationship was observed. These data support the specificity of regional brain MRE measures in support of separable cognitive functions. This report of a structure-function relationship observed with MRE beyond the hippocampus suggests a future role for MRE as a sensitive neuroimaging technique for brain mapping. •Magnetic resonance elastography of the hippocampus and orbitofrontal cortex.•Viscoelasticity of the orbitofrontal cortex correlates with fluid intelligence.•Viscoelasticity of the hippocampus correlates with relational memory.•Double dissociation between structure-function relationships.