Brain imaging and behavior
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Brain Imaging Behav · Jun 2012
ReviewChronic traumatic encephalopathy: neurodegeneration following repetitive concussive and subconcussive brain trauma.
Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease thought to be caused, at least in part, by repetitive brain trauma, including concussive and subconcussive injuries. It is thought to result in executive dysfunction, memory impairment, depression and suicidality, apathy, poor impulse control, and eventually dementia. Beyond repetitive brain trauma, the risk factors for CTE remain unknown. ⋯ Thus far, CTE can only be diagnosed post-mortem. Current research efforts are focused on the creation of clinical diagnostic criteria, finding objective biomarkers for CTE, and understanding the additional risk factors and underlying mechanism that causes the disease. This review examines research to date and suggests future directions worthy of exploration.
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Brain Imaging Behav · Jun 2012
ReviewConcussion in athletics: ongoing clinical and brain imaging research controversies.
Concussion, the most common form of traumatic brain injury, proves to be increasingly complex and not mild in nature as its synonymous term mild traumatic brain injury (mTBI) would imply. Despite the increasing occurrence and prevalence of mTBI there is no universally accepted definition and conventional brain imaging techniques lack the sensitivity to detect subtle changes it causes. ⋯ In this paper the authors review the major findings from these advanced neuroimaging methods along with current controversy within this field of research. As mTBI is frequently associated with youth and sports injury this review focuses on sports-related mTBI in the younger population.
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Brain Imaging Behav · Jun 2012
Multiple resting state network functional connectivity abnormalities in mild traumatic brain injury.
Several reports show that traumatic brain injury (TBI) results in abnormalities in the coordinated activation among brain regions. Because most previous studies examined moderate/severe TBI, the extensiveness of functional connectivity abnormalities and their relationship to postconcussive complaints or white matter microstructural damage are unclear in mild TBI. This study characterized widespread injury effects on multiple integrated neural networks typically observed during a task-unconstrained "resting state" in mild TBI patients. ⋯ Abnormalities not only included functional connectivity deficits, but also enhancements possibly reflecting compensatory neural processes. Postconcussive symptom severity was linked to abnormal regional connectivity within nearly every brain network identified, particularly anterior cingulate. A recently developed multivariate technique that identifies links between whole brain profiles of functional and anatomical connectivity identified several novel mild TBI abnormalities, and represents a potentially important new tool in the study of the complex neurobiological sequelae of TBI.
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Brain Imaging Behav · Jun 2011
Comparative StudyReevaluating brain networks activated during mental imagery of finger movements using probabilistic Tensorial Independent Component Analysis (TICA).
The cerebral and cerebellar networks involved in execution and mental imagery of the same sequential finger movements performed with the non-dominant hand were assessed by 3T functional magnetic resonance imaging using multivariate model-free analysis. Eight right-handed healthy volunteers successively performed execution and mental imagery tasks (sequential thumb to fingers opposition). The same data were analyzed by using (1) the linear General Model (p < 0.05 corrected), and (2) probabilistic tensorial independent component analysis (TICA). ⋯ TICA also showed concomitant activation of (1) a cerebello-thalamo-cortical network during motor execution, and (2) a control executive network during imagination. TICA therefore allows precise identification of the brain networks collaborating in the same performance. TICA constitutes a valuable tool to assess and improve detection of brain networks engaged in mental imagery in comparison with GLM.
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Brain Imaging Behav · Jun 2010
Default network response to a working memory challenge after withdrawal of continuous positive airway pressure treatment for obstructive sleep apnea.
Lower working memory performance and altered brain activity have been reported in studies of obstructive sleep apnea (OSA) patients. However, little is known about the effect of treatment of OSA on brain function, particularly effects on default network processing. We previously reported increased brain response to a working memory challenge in active regions and decreased response in relatively deactivated a priori regions of interest (ROIs) following withdrawal of continuous positive airway pressure (CPAP) treatment. ⋯ Significant further deactivation relative to the treatment adherent baseline was observed in the majority of these ROIs during the withdrawal condition. The magnitude of deactivation during withdrawal was significantly associated with better working memory performance in the posterior cingulate and right postcentral gyrus, and greater sleepiness in the left and right medial frontal gyrus. Results suggest that default network functions are further suspended as a result of a shifting of attention towards a more difficult active task in the context of lowered attentional capacity related to sleepiness.