title: Inferior Prefrontal Cortex Mediates the Relationship between Phosphatidylcholine and Executive Functions in Healthy, Older Adults.
abstract: Objectives:This study examines the neural mechanisms that mediate the relationship between phosphatidylcholine and executive functions in cognitively intact older adults. We hypothesized that higher plasma levels of phosphatidylcholine are associated with better performance on a particular component of the executive functions, namely cognitive flexibility, and that this relationship is mediated by gray matter structure of regions within the prefrontal cortex (PFC) that have been implicated in cognitive flexibility.Methods:We examined 72 cognitively intact adults between the ages of 65 and 75 in an observational, cross-sectional study to investigate the relationship between blood biomarkers of phosphatidylcholine, tests of cognitive flexibility (measured by the Delis-Kaplan Executive Function System Trail Making Test), and gray matter structure of regions within the PFC. A three-step mediation analysis was implemented using multivariate linear regressions and we controlled for age, sex, education, income, depression status, and body mass index.Results:The mediation analysis revealed that gray matter thickness of one region within the PFC, the left inferior PFC (Brodmann's Area 45), mediates the relationship between phosphatidylcholine blood biomarkers and cognitive flexibility.Conclusion:These results suggest that particular nutrients may slow or prevent age-related cognitive decline by influencing specific structures within the brain. This report demonstrates a novel structural mediation between plasma phosphatidylcholine levels and cognitive flexibility. Future work should examine the potential mechanisms underlying this mediation, including phosphatidylcholine-dependent cell membrane integrity of the inferior PFC and phosphatidylcholine-dependent cholinergic projections to the inferior PFC.
authors.affiliation: Decision Neuroscience Laboratory, University of Illinois Urbana-Champaign, UrbanaIL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, UrbanaIL, USA; Neuroscience Program, University of Illinois Urbana-Champaign, UrbanaIL, USA.
authors.forename: Marta K
authors.initials: MK
authors.lastname: Zamroziewicz
authors.affiliation: Decision Neuroscience Laboratory, University of Illinois Urbana-Champaign, UrbanaIL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, UrbanaIL, USA.
authors.forename: Chris E
authors.initials: CE
authors.lastname: Zwilling
authors.affiliation: Decision Neuroscience Laboratory, University of Illinois Urbana-Champaign, UrbanaIL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, UrbanaIL, USA; Neuroscience Program, University of Illinois Urbana-Champaign, UrbanaIL, USA; Department of Psychology, University of Illinois Urbana-Champaign, UrbanaIL, USA; Department of Speech and Hearing Science, University of Illinois Urbana-Champaign, UrbanaIL, USA; Department of Internal Medicine, University of Illinois Urbana-Champaign, UrbanaIL, USA; Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, UrbanaIL, USA; Carle Neuroscience Institute, Carle Foundation Hospital, UrbanaIL, USA.
authors.forename: Aron K
authors.initials: AK
authors.lastname: Barbey
keywords: cognitive aging; executive functions; inferior prefrontal cortex; nutritional cognitive neuroscience; phosphatidylcholine