Journal of neurotrauma
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Journal of neurotrauma · Nov 2024
SYNAPTIC PLASTICITY IN THE INJURED BRAIN DEPENDS ON THE TEMPORAL PATTERN OF STIMULATION.
Neurostimulation protocols are increasingly used as therapeutic interventions, including for brain injury. In addition to the direct activation of neurons, these stimulation protocols are also likely to have downstream effects on those neurons' synaptic outputs. It is well known that alterations in the strength of synaptic connections (long-term potentiation, LTP; long-term depression, LTD) are sensitive to the frequency of stimulation used for induction; however, little is known about the contribution of the temporal pattern of stimulation to the downstream synaptic plasticity that may be induced by neurostimulation in the injured brain. ⋯ In addition to the differences in plasticity outcome between control (naive or sham) and injured brains, the dynamics of the changes in synaptic responses that developed during stimulation were predictive of the final plasticity outcome. Our results demonstrate that the temporal pattern of stimulation plays a role in the polarity and magnitude of synaptic plasticity induced in the cerebral cortex while highlighting differences between normal and injured brain responses. Moreover, these results may be useful for optimization of neurostimulation therapies to treat mTBI and other brain disorders, in addition to providing new insights into downstream plasticity signaling mechanisms in the normal brain.
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Journal of neurotrauma · Nov 2024
Bradykinin 2 receptors (B2R) mediate long term neurocognitive deficits after experimental traumatic brain injury.
The kallikrein-kinin system is one of the first inflammatory pathways to be activated following traumatic brain injury (TBI) and has been shown to exacerbate brain edema formation in the acute phase through activation of bradykinin 2 receptors (B2R). However, the influence of B2R on chronic post-traumatic damage and outcome is unclear. In the current study, we assessed long-term effects of B2R-knockout (KO) after experimental TBI. ⋯ Scar formation and astrogliosis were unaffected, but B2R deficiency led to a gene-dose-dependent attenuation of microglial activation and a reduction of CD45+ cells 3 months after TBI in cortex (p = 0.0003) and hippocampus (p < 0.0001). These results suggest that chronic hippocampal neurodegeneration and subsequent cognitive impairment are mediated by prolonged neuroinflammation and B2R. Inhibition of B2R may therefore represent a novel strategy to reduce long-term neurocognitive deficits after TBI.
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Journal of neurotrauma · Nov 2024
Impact of Sex and Pubertal Development on Anxiety in Adolescents Following Concussion.
Concussion often results in psychological symptoms, including anxiety. Post-concussion anxiety has been well documented, although much of this research has focused on collegiate athletes. The purpose of this study was to compare (1) anxiety symptoms in concussed and healthy controls over time and (2) to explore sex differences in post-concussion anxiety within the context of pubertal development. ⋯ There was a significant three-way interaction between sex, age, and PDSS on SCARED-C total score while controlling for age. Overall, we observed increased anxiety in concussed adolescents, compared with controls, as well as greater post-concussion anxiety reported by females compared with males, including within PDSS groups. Concussion providers should be prepared to receive training to administer well-validated measures of psychopathology and should consider that female adolescents, compared with males, regardless of pubertal development, may be at greater risk for post-concussion anxiety.
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Journal of neurotrauma · Nov 2024
Is There an Optimal Time Window of Placement of Intracranial Pressure (ICP) Monitor for Elderly Patients with Severe Traumatic Brain Injury? An 11-Year Institutional Cohort Study with Restricted Cubic Spline Analysis.
Severe traumatic brain injury (sTBI) is a prominent contributor to both morbidity and mortality in the elderly population. The monitoring of intracranial pressure (ICP) is crucial in the management of sTBI patients. Nevertheless, the appropriate timing for the placement of ICP monitor in elderly sTBI patients remains uncertain. ⋯ The relationship between ICP placement and in-hospital mortality was non-linear, exhibiting an inverted U-shaped curve in elderly patients with sTBI. For elderly patients with sTBI, early (≤ 6 h) ICP placement was associated with reduced in-hospital mortality. The clinical benefit of ICP placement decreased beyond the optimal time window.