Journal of neurotrauma
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Journal of neurotrauma · Mar 2017
Primary blast injury depressed hippocampal long-term potentiation through disruption of synaptic proteins.
Blast-induced traumatic brain injury (bTBI) is a major threat to United States service members in military conflicts worldwide. The effects of primary blast, caused by the supersonic shockwave interacting with the skull and brain, remain unclear. Our group has previously reported that in vitro primary blast exposure can reduce long-term potentiation (LTP), the electrophysiological correlate of learning and memory, in rat organotypic hippocampal slice cultures (OHSCs) without significant changes to cell viability or basal, evoked neuronal function. ⋯ Blast also reduced the expression of postsynaptic density protein-95 (PSD-95) and phosphorylation of stargazin protein at the serine-239/240 site. Finally, we found that modulation of the cyclic adenosine monophosphate (cAMP) pathway ameliorated electrophysiological and protein-expression changes caused by blast. These findings could inform the development of novel therapies to treat blast-induced loss of neuronal function.
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Journal of neurotrauma · Mar 2017
Electrophysiological Correlates of Word Retrieval in Traumatic Brain Injury.
Persons who have had a traumatic brain injury (TBI) often have word retrieval deficits; however, the underlying neural mechanisms of such deficits are yet to be clarified. Previous studies in normal subjects have shown that during a word retrieval task, there is a 750 msec event-related potential (ERP) divergence detected at the left fronto-temporal region when subjects evaluate word pairs that facilitate retrieval compared with responses elicited by word pairs that do not facilitate retrieval. In this study, we investigated the neurophysiological correlates of word retrieval networks in 19 retired professional athletes with TBI and 19 healthy control (HC) subjects. ⋯ The EEG showed a significant group by condition interaction over the left fronto-temporal region. The HC group mean amplitudes were significantly different between conditions, but the TBI group data did not show this difference, suggesting neurophysiological effects of injury. These findings provide evidence that ERP amplitudes may be used as a marker of disrupted semantic retrieval circuits in persons with TBI even when those persons perform normally.
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Journal of neurotrauma · Mar 2017
Controlled Clinical TrialCerebral Perfusion changes in Post-Concussion Syndrome: A prospective controlled cohort study.
The biology of post-concussive symptoms is unclear. Symptoms are often increased during activities, and have been linked to decreased cerebrovascular reactivity and perfusion. The aim of this study was to examine cerebral blood flow (CBF) in children with different clinical recovery patterns following mild traumatic brain injury (mTBI). ⋯ Symptomatic children have higher CBF. Children who "recovered" quickly, have decreased CBF suggesting that clinical recovery precedes the cerebral recovery. Further longitudinal studies are required to determine if these perfusion patterns continue to change over time.
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Journal of neurotrauma · Mar 2017
Altered wiring of the human structural connectome in adults with mild traumatic brain injury.
In this study, structural connectivity after mild traumatic brain injury (mTBI) was examined from a network perspective, with a particular focus on post-traumatic complaints. Fifty-three patients with and without self-reported complaints at 2 weeks after uncomplicated mTBI were included, in addition to 20 matched healthy controls. Diffusion weighted imaging was performed at 4 weeks post-injury, and neuropsychological tests measuring processing speed and verbal memory were administered at 3 months post-injury to determine cognitive outcome. ⋯ Additionally, significant correlations were found between higher betweenness centrality values of language areas and lower verbal memory scores in patients with mTBI. In conclusion, our findings may indicate that global graph measures of the structural connectome are associated with pre- and/or non-injury-related factors that determine the susceptibility to developing (persistent) complaints after mTBI. Further, correlations between graph measures and neuropsychological test scores could suggest early compensatory mechanisms to maintain adequate cognitive performance.
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Journal of neurotrauma · Mar 2017
[18F]FDG-PET Combined with MRI Elucidates the Pathophysiology of Traumatic Brain Injury in Rats.
Non-invasive measurements of brain metabolism using 18F-fluorodeoxyglucose (FDG) with positron emission tomography (PET) may provide important information about injury severity following traumatic brain injury (TBI). There is growing interest in the potential of combining functional PET imaging with anatomical and functional magnetic resonance imaging (MRI). This study aimed to investigate the effectiveness of combining clinically available FDG-PET with T2 and diffusion MR imaging, with a particular focus on inflammation and the influence of glial alterations after injury. ⋯ Glial activation was not detected in the amygdala but neuronal damage was evident, as the amygdala was the only region to show a reduction in both FDG uptake and ADC at sub-acute time-points. Overall, FDG-PET detected glial activation but was confounded by the presence of cell damage, whereas MRI consistently detected cell damage but was confounded by glial activation. These results demonstrate that FDG-PET and MRI can be used together to improve our understanding of the complex alterations in the brain after TBI.