title: Age-related differences in working memory evoked gamma oscillations.
abstract: OBJECTIVE
  Working memory is associated with gamma oscillations (30-50 Hz). Previous studies have demonstrated altered gamma oscillations in the elderly population that may be related to general cognitive decline. However, it is unknown how gamma oscillations change with age or if there is an age when gamma oscillations optimally mediate working memory performance. That is, gamma oscillations may be maximal in middle-aged adults compared to younger and elderly adults. The objective of this study was to evaluate working memory evoked gamma oscillations in adults aged 19-29 years (mean 23.32 ± 2.85 1 SD) compared to adults aged 30-60 years (mean 39.10 ± 8.11 1 SD).
  
  
  METHODS
  Subjects completed the verbal N-back task administered at four working loads (0, 1, 2, 3), while electroencephalography (EEG) was collected. Gamma power was measured during correct responses.
  
  
  RESULTS
  Reduced gamma oscillations were observed in the adults aged 19-29 compared to those aged 30-60 years. Age was found to be positively related to the power of gamma oscillations. No differences were found on N-Back accuracy.
  
  
  CONCLUSIONS
  Increased working memory evoked gamma oscillatory activity may provide a neurophysiological marker in the healthy aging brain.
authors.affiliation: Biobehavioural Addictions and Concurrent Disorders Laboratory (BACDRL), Schizophrenia Division, Complex Mental Illness Program Center for Addiction and Mental Health, 250 College Street, M5T 1R8 Toronto, Ontario, Canada; Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, 1001 Queen Street West, M6J 1H4 Toronto, Ontario, Canada; Department of Psychiatry, Brain and Therapeutics Division, University of Toronto, 250 College Street, M5T 1R8 Toronto, Ontario, Canada. Electronic address: Mera.Barr@camh.ca.
authors.forename: Mera S
authors.initials: MS
authors.lastname: Barr
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, 1001 Queen Street West, M6J 1H4 Toronto, Ontario, Canada.
authors.forename: Natasha
authors.initials: N
authors.lastname: Radhu
authors.affiliation: School of Kinesiology and Health Science, York University, 4700 Keele Street, M3J 1P3 Toronto, Ontario, Canada.
authors.forename: Crissa L
authors.initials: CL
authors.lastname: Guglietti
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, 1001 Queen Street West, M6J 1H4 Toronto, Ontario, Canada.
authors.forename: Reza
authors.initials: R
authors.lastname: Zomorrodi
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, 1001 Queen Street West, M6J 1H4 Toronto, Ontario, Canada; Department of Psychiatry, Brain and Therapeutics Division, University of Toronto, 250 College Street, M5T 1R8 Toronto, Ontario, Canada.
authors.forename: Tarek K
authors.initials: TK
authors.lastname: Rajji
authors.affiliation: School of Kinesiology and Health Science, York University, 4700 Keele Street, M3J 1P3 Toronto, Ontario, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Ritvo
authors.affiliation: Temerty Centre for Therapeutic Brain Intervention, Centre for Addiction and Mental Health, 1001 Queen Street West, M6J 1H4 Toronto, Ontario, Canada; Department of Psychiatry, Brain and Therapeutics Division, University of Toronto, 250 College Street, M5T 1R8 Toronto, Ontario, Canada.
authors.forename: Zafiris J
authors.initials: ZJ
authors.lastname: Daskalakis
mesh_terms: D000328:Adult; D000375:Aging / Q000523:psychology*; D001921:Brain / Q000502:physiology; D004522:Educational Status; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D065818:Gamma Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D011930:Reaction Time; D012016:Reference Values; D014706:Verbal Learning / Q000502:physiology; D055815:Young Adult
keywords: Age; EEG; Frontal brain region; Gamma oscillation; Working memory