title: Salient measures of inhibition and switching are associated with frontal lobe gray matter volume in healthy middle-aged and older adults.
abstract: OBJECTIVE
  To investigate brain-behavior relationships between morphometric brain measures and salient executive function (EF) measures of inhibition and switching.
  
  
  METHODS
  One hundred participants (49-80 years) performed the Color Word Interference Test from the Delis-Kaplan Executive Function System (D-KEFS). Salient measures of EF components of inhibition and switching, of which the effect of more fundamental skills were regressed out, were analyzed using linear models and a conditional inference trees analysis taking intercorrelations between predictor variables (brain volumes, age, gender, and education) into account.
  
  
  RESULTS
  The conditional inference trees analysis demonstrated a primary role of the middle frontal gyrus (MFG) in explaining variations in the salient EF measure of switching and combined inhibition/switching. Age predicted measures of inhibition.
  
  
  CONCLUSIONS
  The study highlights the importance of considering fundamental cognitive skills and the use of a statistical method taking possible complex relationships between predictor variables into account when interpreting standard EF test results. Further studies should include MRI measures representing neural networks that may relate to CWIT performance, and longitudinal studies are required to investigate any causal relationships.
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen.
authors.forename: Steinunn
authors.initials: S
authors.lastname: Adólfsdóttir
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen.
authors.forename: Judit
authors.initials: J
authors.lastname: Haász
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen.
authors.forename: Eike
authors.initials: E
authors.lastname: Wehling
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen.
authors.forename: Martin
authors.initials: M
authors.lastname: Ystad
authors.affiliation: Department of Biomedicine, Neuroinformatics, and Image Analysis Laboratory, University of Bergen.
authors.forename: Arvid
authors.initials: A
authors.lastname: Lundervold
authors.affiliation: Department of Biological and Medical Psychology, University of Bergen.
authors.forename: Astri J
authors.initials: AJ
authors.lastname: Lundervold
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000502:physiology; D056344:Executive Function / Q000502:physiology; D005260:Female; D005625:Frontal Lobe / Q000033:anatomy & histology* / Q000502:physiology*; D066128:Gray Matter / Q000033:anatomy & histology* / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D007266:Inhibition, Psychological; D016014:Linear Models; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests