title: Anterior cingulate cortex mediates the relationship between O3PUFAs and executive functions in APOE e4 carriers.
abstract: BACKGROUND
  Although diet has a substantial influence on the aging brain, the relationship between biomarkers of diet and aspects of brain health remains unclear. This study examines the neural mechanisms that mediate the relationship between omega-3 polyunsaturated fatty acids (O3PUFAs) and executive functions in at-risk (APOE e4 carriers), cognitively intact older adults. We hypothesized that higher levels of O3PUFAs are associated with better performance in a particular component of the executive functions, namely cognitive flexibility, and that this relationship is mediated by gray matter volume of a specific region thought to be important for cognitive flexibility, the anterior cingulate cortex.
  
  
  METHODS
  We examined 40 cognitively intact adults between the ages of 65 and 75 with the APOE e4 polymorphism to investigate the relationship between biomarkers of O3PUFAs, tests of cognitive flexibility (measured by the Delis-Kaplan Executive Function System Trail Making Test), and gray matter volume within regions of the prefrontal cortex (PFC).
  
  
  RESULTS
  A mediation analysis revealed that gray matter volume within the left rostral anterior cingulate cortex partially mediates the relationship between O3PUFA biomarkers and cognitive flexibility.
  
  
  CONCLUSIONS
  These results suggest that the anterior cingulate cortex acts as a mediator of the relationship between O3PUFAs and cognitive flexibility in cognitively intact adults thought to be at risk for cognitive decline. Through their link to executive functions and neuronal measures of PFC volume, O3PUFAs show potential as a nutritional therapy to prevent dysfunction in the aging brain.
authors.affiliation: Decision Neuroscience Laboratory, University of Illinois Urbana, IL, USA ; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana, IL, USA ; Neuroscience Program, University of Illinois Champaign, IL, USA.
authors.forename: Marta K
authors.initials: MK
authors.lastname: Zamroziewicz
authors.affiliation: Decision Neuroscience Laboratory, University of Illinois Urbana, IL, USA ; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana, IL, USA.
authors.forename: Erick J
authors.initials: EJ
authors.lastname: Paul
authors.affiliation: Decision Neuroscience Laboratory, University of Illinois Urbana, IL, USA ; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana, IL, USA ; Carle Neuroscience Institute, Carle Foundation Hospital Urbana, IL, USA.
authors.forename: Rachael D
authors.initials: RD
authors.lastname: Rubin
authors.affiliation: Decision Neuroscience Laboratory, University of Illinois Urbana, IL, USA ; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana, IL, USA ; Neuroscience Program, University of Illinois Champaign, IL, USA ; Department of Speech and Hearing Science, University of Illinois Champaign, IL, USA ; Department of Internal Medicine, University of Illinois Champaign, IL, USA ; Institute for Genomic Biology, University of Illinois Champaign, IL, USA ; Department of Psychology, University of Illinois Champaign, IL, USA.
authors.forename: Aron K
authors.initials: AK
authors.lastname: Barbey
keywords: anterior cingulate cortex; cognitive aging; executive function; nutritional neuroscience; omega-3 fatty acids