title: Age-related changes in intracortical inhibition are mental-cognitive state-dependent.
abstract: BACKGROUND
  This study aimed to assess the impact of aging and 'state-dependency' on cortical excitability. Two studies investigated these factors using a motor task and found that the age-related differences observed at rest disappeared in the task condition. However, as both their tasks and excitability measurements involved the motor cortex, their results could be specific only to the motor system. To overcome this problem, the present study used a cognitive task to control mental state.
  
  
  METHODS
  Intracortical inhibition/facilitation (ICI/ICF) were assessed in young and older adults at rest and during the cognitive task. The cortical silent period (CSP) was also evaluated.
  
  
  RESULTS
  ICI and CSP were reduced with aging. However, ICI differences between young and old people disappeared when they performed the cognitive task.
  
  
  CONCLUSIONS
  Age and mental state modify cortical excitability. Taking these factors into consideration is crucial to clinical research using cortical excitability as a possible biomarker of pathology.
authors.affiliation: Laboratoire de Psychologie et Neurocognition, CNRS UMR 5105, Université Pierre Mendes France, BP 47, 38040 Grenoble Cedex 9, France. Electronic address: Lysianne.Beynel@upmf-grenoble.fr.
authors.forename: Lysianne
authors.initials: L
authors.lastname: Beynel
authors.affiliation: Laboratoire de Psychologie et Neurocognition, CNRS UMR 5105, Université Pierre Mendes France, BP 47, 38040 Grenoble Cedex 9, France. Electronic address: Alan.Chauvin@upmf-grenoble.fr.
authors.forename: Alan
authors.initials: A
authors.lastname: Chauvin
authors.affiliation: GIPSA-Lab, UMR CNRS 5216, 11 rue des Mathématiques Grenoble Campus, BP46, 38402 Saint Martin d'Heres Cedex Grenoble, France. Electronic address: Nathalie.Guyader@gipsa-lab.grenoble-inp.fr.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Guyader
authors.affiliation: Laboratoire de Psychologie et Neurocognition, CNRS UMR 5105, Université Pierre Mendes France, BP 47, 38040 Grenoble Cedex 9, France; IRMaGe, CNRS UMR 5105, Unité IRM 3T Recherche, CHU Grenoble - CS 10217, 38 043 Grenoble Cedex 9, France. Electronic address: Sylvain.Harquel@upmf-grenoble.fr.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Harquel
authors.affiliation: Laboratoire de Psychologie et Neurocognition, CNRS UMR 5105, Université Pierre Mendes France, BP 47, 38040 Grenoble Cedex 9, France. Electronic address: Christian.Marendaz@upmf-grenoble.fr.
authors.forename: Christian
authors.initials: C
authors.lastname: Marendaz
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology; D066191:Sensorimotor Cortex / Q000502:physiology*; D055815:Young Adult
keywords: Aging; Cortical excitability; State-dependency; Transcranial magnetic stimulation