title: A meta-analysis of the effects of aging on motor cortex neurophysiology assessed by transcranial magnetic stimulation.
abstract: OBJECTIVE
  Transcranial magnetic stimulation (TMS) is a non-invasive tool used for studying cortical excitability and plasticity in the human brain. This review aims to quantitatively synthesize the literature on age-related differences in cortical excitability and plasticity, examined by TMS.
  
  
  METHODS
  A literature search was conducted using MEDLINE, Embase, and PsycINFO from 1980 to December 2015. We extracted studies with healthy old (50-89years) versus young (16-49years) individuals that utilized the following TMS measures: resting motor threshold (RMT), short-interval cortical inhibition (SICI), short-latency afferent inhibition (SAI), cortical silent period (CSP), intracortical facilitation (ICF), and paired associative stimulation (PAS).
  
  
  RESULTS
  We found a significant increase in RMT (g=0.414, 95% confidence interval (CI) [0.284, 0.544], p<0.001), a significant decrease in SAI (g=0.778, 95% CI [0.478, 1.078], p<0.001), and a trending decrease in LTP-like plasticity (g=-0.528, 95% CI [-1.157, 0.100] p<0.1) with age.
  
  
  CONCLUSIONS
  Our findings suggest an age-dependent reduction in cortical excitability and sensorimotor integration within the human motor cortex.
  
  
  CONCLUSIONS
  Alterations in the ability to regulate cortical excitability, sensorimotor integration and plasticity may underlie several age-related motor deficits.
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada.
authors.forename: Apoorva
authors.initials: A
authors.lastname: Bhandari
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada.
authors.forename: Natasha
authors.initials: N
authors.lastname: Radhu
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
authors.forename: Faranak
authors.initials: F
authors.lastname: Farzan
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
authors.forename: Benoit H
authors.initials: BH
authors.lastname: Mulsant
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
authors.forename: Tarek K
authors.initials: TK
authors.lastname: Rajji
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
authors.forename: Zafiris J
authors.initials: ZJ
authors.lastname: Daskalakis
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, Toronto, Ontario M6J 1H4, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario M5T 1R8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada. Electronic address: daniel.blumberger@camh.ca.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Blumberger
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: Aging; Cortical excitability; Cortical plasticity; Gamma-aminobutyric acid; Motor cortex; Transcranial magnetic stimulation