title: Colour or shape: examination of neural processes underlying mental flexibility in posttraumatic stress disorder.
abstract: Posttraumatic stress disorder (PTSD) is a mental disorder that stems from exposure to one or more traumatic events. While PTSD is thought to result from a dysregulation of emotional neurocircuitry, neurocognitive difficulties are frequently reported. Mental flexibility is a core executive function that involves the ability to shift and adapt to new information. It is essential for appropriate social-cognitive behaviours. Magnetoencephalography (MEG), a neuroimaging modality with high spatial and temporal resolution, has been used to track the progression of brain activation during tasks of mental flexibility called set-shifting. We hypothesized that the sensitivity of MEG would be able to capture the abnormal neurocircuitry implicated in PTSD and this would negatively impact brain regions involved in set-shifting. Twenty-two soldiers with PTSD and 24 matched control soldiers completed a colour-shape set-shifting task. MEG data were recorded and source localized to identify significant brain regions involved in the task. Activation latencies were obtained by analysing the time course of activation in each region. The control group showed a sequence of activity that involved dorsolateral frontal cortex, insula and posterior parietal cortices. The soldiers with PTSD showed these activations but they were interrupted by activations in paralimbic regions. This is consistent with models of PTSD that suggest dysfunctional neurocircuitry is driven by hyper-reactive limbic areas that are not appropriately modulated by prefrontal cortical control regions. This is the first study identifying the timing and location of atypical neural responses in PTSD with set-shifting and supports the model that hyperactive limbic structures negatively impact cognitive function.
authors.affiliation: 1] Division of Neurology, Hospital for Sick Children, Toronto, ON, Canada [2] Neurosciences and Mental Health, SickKids Research Institute, Toronto, ON, Canada [3] Department of Paediatrics, University of Toronto, Toronto, ON, Canada.
authors.forename: E W
authors.initials: EW
authors.lastname: Pang
authors.affiliation: Canadian Forces Health Services, Operational Trauma and Stress Support Centre, Ottawa, ON, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Sedge
authors.affiliation: Military Medicine Section, Canadian Forces Environmental Medicine Establishment, Toronto, ON, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Grodecki
authors.affiliation: Neurosciences and Mental Health, SickKids Research Institute, Toronto, ON, Canada.
authors.forename: A
authors.initials: A
authors.lastname: Robertson
authors.affiliation: Neurosciences and Mental Health, SickKids Research Institute, Toronto, ON, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: MacDonald
authors.affiliation: Canadian Forces Health Services, Directorate of Mental Health, Ottawa, ON, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Jetly
authors.affiliation: Military Medicine Section, Defence Research and Development Canada, Toronto, ON, Canada.
authors.forename: P N
authors.initials: PN
authors.lastname: Shek
authors.affiliation: 1] Neurosciences and Mental Health, SickKids Research Institute, Toronto, ON, Canada [2] Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, ON, Canada [3] Department of Medical Imaging, University of Toronto, Toronto, ON, Canada.
authors.forename: M J
authors.initials: MJ
authors.lastname: Taylor
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D002170:Canada; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D003118:Color Perception / Q000502:physiology*; D003130:Combat Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D056344:Executive Function / Q000502:physiology*; D006801:Humans; D008032:Limbic System / Q000503:physiopathology; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D017397:Prefrontal Cortex / Q000503:physiopathology; D011340:Problem Solving / Q000502:physiology*; D012718:Set, Psychology; D013313:Stress Disorders, Post-Traumatic / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D014728:Veterans / Q000523:psychology*
references.citation: Proc Natl Acad Sci U S A. 2008 Aug 26;105(34):12569-74
references.pmid: 18723676
references.citation: J Cogn Neurosci. 2000 Jan;12(1):142-62
references.pmid: 10769312
references.citation: Neuroimage. 2011 Jan;54 Suppl 1:S62-8
references.pmid: 20483375
references.citation: Neurosci Biobehav Rev. 2006;30(7):1004-31
references.pmid: 16730374
references.citation: J Trauma Stress. 2010 Apr;23(2):292-5
references.pmid: 20419740
references.citation: J Nucl Med. 1994 Jun;35(6):929-34
references.pmid: 8195877
references.citation: Cogn Behav Neurol. 2010 Jun;23(2):124-9
references.pmid: 20535062
references.citation: Arch Intern Med. 2006 May 22;166(10):1092-7
references.pmid: 16717171
references.citation: Neuropsychologia. 1998 Mar;36(3):273-93
references.pmid: 9622192
references.citation: J Abnorm Psychol. 2006 Aug;115(3):484-95
references.pmid: 16866589
references.citation: J Neuropsychiatry Clin Neurosci. 1993 Spring;5(2):183-8
references.pmid: 8508036
references.citation: Arch Gen Psychiatry. 2005 Mar;62(3):273-81
references.pmid: 15753240
references.citation: Psychosom Med. 2009 May;71(4):373-7
references.pmid: 19398499
references.citation: Neuroimage. 2003 Aug;19(4):1589-601
references.pmid: 12948714
references.citation: Front Neurosci. 2008 Jul 07;2(1):79-85
references.pmid: 18982110
references.citation: Proc Natl Acad Sci U S A. 2002 May 28;99(11):7803-8
references.pmid: 12032364
references.citation: Hippocampus. 2005;15(6):798-807
references.pmid: 15988763
references.citation: Behav Res Ther. 1996 Aug;34(8):669-73
references.pmid: 8870294
references.citation: Neurosci Biobehav Rev. 2012 Oct;36(9):2130-42
references.pmid: 22766141
references.citation: J Neurosci. 2001 Oct 1;21(19):7733-41
references.pmid: 11567063
references.citation: Nat Rev Neurosci. 2012 Nov;13(11):769-87
references.pmid: 23047775
references.citation: Methods. 2001 Oct;25(2):249-71
references.pmid: 11812209
references.citation: Brain Cogn. 2014 Apr;86:90-7
references.pmid: 24607731
references.citation: Neuropsychology. 2002 Jan;16(1):5-14
references.pmid: 11853357
references.citation: Neuroimage. 2006 Apr 15;30(3):1038-49
references.pmid: 16414280
references.citation: Expert Rev Neurother. 2011 Feb;11(2):275-85
references.pmid: 21306214
references.citation: Biol Psychiatry. 2006 Apr 1;59(7):582-7
references.pmid: 16165099
references.citation: Depress Anxiety. 2013 Mar;30(3):207-16
references.pmid: 23319445
references.citation: Neuroreport. 2012 Mar 7;23(4):234-9
references.pmid: 22222502
references.citation: Hum Brain Mapp. 2002 Jan;15(1):1-25
references.pmid: 11747097
references.citation: J Abnorm Psychol. 2007 Aug;116(3):448-63
references.pmid: 17696700
references.citation: J Psychiatry Neurosci. 2010 Mar;35(2):80-9
references.pmid: 20184804
references.citation: Neuroimage. 2004 Nov;23(3):983-96
references.pmid: 15528099
references.citation: J Gen Intern Med. 2001 Sep;16(9):606-13
references.pmid: 11556941
references.citation: Hum Brain Mapp. 2009 Aug;30(8):2530-41
references.pmid: 19072895
references.citation: Neuropsychol Rev. 2012 Mar;22(1):21-34
references.pmid: 22350690
references.citation: Proc Natl Acad Sci U S A. 2003 Jul 22;100(15):9039-43
references.pmid: 12853571
references.citation: J Int Neuropsychol Soc. 2009 Nov;15(6):826-9
references.pmid: 19891816