Journal of neurotrauma
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Journal of neurotrauma · Jan 2018
Post-injury administration of galantamine reduces traumatic brain injury pathology and improves outcome.
Acetylcholine is an excitatory neurotransmitter in the central nervous system that plays a key role in cognitive function, including learning and memory. Previous studies have shown that experimental traumatic brain injury (TBI) reduces cholinergic neurotransmission, decreases evoked release of acetylcholine, and alters cholinergic receptor levels. Galantamine (U. ⋯ Specifically, significant improvements in the Morris water maze, novel object recognition, and context-specific fear memory tasks were observed in injured animals treated with galantamine. Although messenger RNAs for both M1 (Nos2, TLR4, and IL-12ß) and M2 (Arg1, CCL17, and Mcr1) microglial phenotypes were elevated post-TBI, galantamine treatment did not alter microglial polarization tested 24 h and 6 days post-injury. Taken together, these findings support the further investigation of galantamine as a treatment for TBI.
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Journal of neurotrauma · Jan 2018
Transcranial Doppler Systolic Flow Index and ICP Derived Cerebrovascular Reactivity Indices in TBI.
The purpose of our study was to explore relationships between transcranial Doppler (TCD) indices of cerebrovascular reactivity and those derived from intracranial pressure (ICP). Goals included: A) confirming previously described co-variance patterns of TCD/ICP indices, and B) describing thresholds for systolic flow index (Sx; correlation between systolic flow velocity [FVs] and cerebral perfusion pressure [CPP]) associated with outcome. In a retrospective cohort of traumatic brain injury (TBI) patients: with TCD and ICP monitoring, we calculated various continuous indices of cerebrovascular reactivity: A) ICP (pressure reactivity index [PRx]: correlation between ICP and mean arterial pressure [MAP]; PAx: correlation between pulse amplitude of ICP [AMP] and MAP; RAC: correlation between AMP and CPP) and B) TCD (mean flow index [Mx]: correlation between mean flow velocity [FVm] and CPP; Mx_a: correlation between FVm and MAP; Sx: correlation between FVs and CPP; Sx_a: correlation between FVs and MAP; Dx: correlation between diastolic flow velocity [FVd] and CPP; Dx_a: correlation between FVd and MAP). ⋯ TCD systolic indices are most closely associated with ICP indices. Sx and Sx_a likely provide better approximation of ICP indices, compared with Mx/Mx_a/Dx/Dx_a. Sx provides superior outcome prediction, versus Mx, with defined thresholds.
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Journal of neurotrauma · Jan 2018
Concussion alters the functional brain processes of visual attention and working memory.
Millions of North Americans sustain a concussion or a mild traumatic brain injury annually, and are at risk of cognitive, emotional, and physical sequelae. Although functional MRI (fMRI) studies have provided an initial framework for examining functional deficits induced by concussion, particularly working memory and attention, the temporal dynamics underlying these deficits are not well understood. We used magnetoencephalography (MEG), a modality with millisecond temporal resolution, in conjunction with a 1-back visual working memory (VWM) paradigm using scenes from everyday life to characterize spatiotemporal functional differences at specific VWM stages, in adults had had or had not had a recent concussion. ⋯ Parietal hypoactivation, starting at 60 ms during encoding, was correlated with symptom severity, possibly linked to impaired top-down attentional processing. Hyperactivation in the scene-selective occipitotemporal areas, the medial temporal complex, specifically the right hippocampus and orbitofrontal areas during encoding and/or recognition, lead us to posit inefficient but compensatory visuoperceptual, relational, and retrieval processing. Although injuries sustained after the concussion were considered "mild," these data suggest that they can have prolonged effects on early attentional and VWM processes.
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Journal of neurotrauma · Jan 2018
SKELETAL MUSCLE ATROPHY AND DEGENERATION IN A MOUSE MODEL OF TRAUMATIC BRAIN INJURY.
Atrophy is thought to be a primary mode of muscle loss in neuromuscular injuries. The differential effects of central and peripheral injuries on atrophy and degeneration/regeneration in skeletal muscle tissue have not been well described. This study investigated skeletal muscle atrophy and degeneration/regeneration in an animal model of traumatic brain injury (TBI). ⋯ Injured soleus FAs were smaller than sham soleus (p = 0.02) and injured TA (p < 0.001). Mean CNs were higher in the TBI-injured TA than in other muscles. Differential TBI-induced atrophy and degeneration/regeneration in lower limb muscles suggests that muscle responses to cortical injury involve more complex changes than those observed with simple disuse atrophy.
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Journal of neurotrauma · Jan 2018
REPEATED EXPOSURE TO EXPERIMENTAL PAIN DIFFERENTIATES COMBAT TBI WITH AND WITHOUT PTSD.
Mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) are highly comorbid conditions that often co-occur with chronic pain. We have shown that women with PTSD subsequent to intimate partner violence show attenuated brain response to repeated experimental pain that was related to symptoms of avoidance. The aim of this study was to extend our past findings to males with combat trauma and to examine brain response to experimental pain in men with and without PTSD who sustained mTBI during combat. ⋯ The current study provides further evidence that repeated exposure to brief painful stimuli results in attenuation of insula activation over time in traumatized individuals. Further, in PTSD, AI shows greatest attenuation in those with the highest level of avoidance-a finding that was replicated across diverse samples. Thus, this mechanism may be a generalized mechanism of maladaptive response to experimental pain in those with significant trauma.