title: Proactive Response Inhibition and Subcortical Gray Matter Integrity in Traumatic Brain Injury.
abstract: Traumatic brain injury (TBI) has been associated with impairments in inhibiting prepotent motor responses triggered by infrequent external signals (ie, reactive inhibition). It is unclear whether proactive preparation to inhibit upcoming responses is also affected (ie, proactive inhibition). Successful inhibition relies on frontosubcortical interactions; therefore, impairments might be linked with gray matter atrophy in subcortical structures.
  
  
  
  We investigated reactive and proactive inhibition in TBI and control groups, and their relationship with subcortical gray matter.
  
  
  
  Participants performed a response inhibition task in which the probability of stopping was manipulated. Reactive inhibition was measured as the stop-signal reaction time (SSRT) when the probability of stopping was low. Proactive inhibition was measured as the change in SSRT and in go response time with increasing probability of stopping. Subcortical gray matter structures were automatically segmented with FSL-FIRST. Group differences in subregional volume and associations with reactive and proactive inhibition efficiency were investigated using shape analysis.
  
  
  
  Reactive inhibition was impaired in TBI, as indicated by longer SSRTs. Moreover, the degree of atrophy in subregions of subcortical structures was predictive for SSRT in TBI. In contrast, proactive inhibition was not affected because both groups showed no response time slowing as a function of stopping probability. Proactive inhibition efficiency could be predicted by local volume in the anterior left putamen, bilateral pallidum, and right thalamus in controls but not in TBI.
  
  
  
  Our results reveal that proactive inhibition seems unaffected in TBI and that volume of subregions of subcortical nuclei is predictive for response inhibition proficiency and of clinical relevance in TBI.
authors: 1 Movement Control and Neuroplasticity Research Group, Biomedical Sciences Group, KU Leuven, Belgium.
authors: Lize
authors: L
authors: Hermans
authors: 2 Center for Epilepsy and Acquired Brain Injury (CEPOS), Duffel, Belgium.
authors: Kurt
authors: K
authors: Beeckmans
authors: 3 Department of Physical Medicine and Rehabilitation, University Hospital Leuven - Campus Pellenberg, Belgium.
authors: Karla
authors: K
authors: Michiels
authors: 4 Rehabilitation Hospital RevArte, Edegem, Belgium.
authors: Christophe
authors: C
authors: Lafosse
authors: 5 Medical Imaging Center, Group Biomedical Sciences, KU Leuven, Belgium.
authors: Stefan
authors: S
authors: Sunaert
authors: 6 School of Psychological Sciences and Monash Institute of Cognitive and Clinical Neurosciences, Monash University, Australia.
authors: James P
authors: JP
authors: Coxon
authors: 1 Movement Control and Neuroplasticity Research Group, Biomedical Sciences Group, KU Leuven, Belgium.|7 Leuven Research Institute for Neuroscience & Disease (LIND), Leuven, Belgium.
authors: Stephan P
authors: SP
authors: Swinnen
authors: 1 Movement Control and Neuroplasticity Research Group, Biomedical Sciences Group, KU Leuven, Belgium.
authors: Inge
authors: I
authors: Leunissen
mesh_terms: D000293:Adolescent; D000328:Adult; D001284:Atrophy; D001921:Brain / Q000000981:diagnostic imaging*; D000070642:Brain Injuries, Traumatic / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging*; D006225:Hand / Q000503:physiopathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009483:Neuropsychological Tests; D009929:Organ Size; D010363:Pattern Recognition, Automated; D011334:Proactive Inhibition; D011930:Reaction Time; D011931:Reactive Inhibition; D055815:Young Adult
keywords: basal ganglia; brain injuries; proactive inhibition; reactive inhibition; shape analysis; stop signal