Brain research
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Premotor cortex activity is associated with complex motor performance and motor learning and offers a potential target to improve dexterity by transcranial direct current stimulation (tDCS). We explored the effects of tDCS of premotor cortex on performance of a Strength-Dexterity test in healthy subjects. ⋯ This study demonstrates that tDCS over the left premotor cortex can improve performance of a dexterity demanding task. The effective polarity of stimulation depends on the task performance strategies. The study moreover shows a functional relevance of interactions between the left and right premotor cortex.
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By means of "task free" resting-state functional magnetic resonance imaging (rs-fMRI), abnormal functional connectivity (FC) of the default mode network (DMN) in cirrhotic patients with hepatic encephalopathy (HE) has been reported; however, little is known about the changes of DMN in cirrhotic patients without overt or minimal HE. The aim of this study was to investigate whether there was a disruption of the FC within the DMN in patients with hepatitis B virus (HBV)-related cirrhosis without any signs of HE. Fifty one patients with HBV-related cirrhosis without HE and 61 age- and gender-matched healthy controls underwent the rs-fMRI. ⋯ Compared with the controls, patients with HBV-related cirrhosis without HE demonstrated significantly decreased region-to-region FC between the mPFC and bilateral MTL, right HF, and left IPC, as well as between the right MTL and left IPC, right HF, and PCC. A significant negative relationship was observed between blood ammonia levels and connectivity strength between the mPFC and left IPC in patients. These results suggest that patients with HBV-related cirrhosis without HE had disrupted functional connectivty within the DMN, even before the appearance of minimal HE.
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Animal models of traumatic brain injury (TBI) are essential for testing novel hypotheses and therapeutic interventions. Unfortunately, due to the broad heterogeneity of TBI in humans, no single model has been able to reproduce the entire spectrum of these injuries. The controlled cortical impact (CCI) model is one of the most commonly used models of contusion TBI. ⋯ Furthermore, adhesive removal test showed significant somatosensory and motor deficits only in the S-CCI groups. Histological analysis showed a large extent of cortical contusion lesions, including both the sensory and motor cortex, and hippocampal damage in the S-CCI. These findings collectively suggest that the current model may offer sensitive, reliable, and clinically relevant outcomes for assessments of therapeutic strategies for TBI.
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Neural stem cell (NSC) transplantation has been reported to be a leading strategy to stimulate neuroplasticity, repair neuronal loss and promote the morphologic and functional recovery of spinal cord injury (SCI). However, massive death of transplanted NSCs is still a problem, which is considered to be related to a series of pro-inflammatory cytokines that induce apoptosis, extensive demyelination and axonal destruction. Tumor necrosis factor alpha (TNF-α), as one of the major inflammation initiators, contributes to secondary neural cell death. ⋯ We observed most abundant NF-positive fibers after the combination treatment, indicating that combination therapy retained and promoted neural regeneration. Finally, the early suppression of TNF-α reduced the occurrence of demyelination, and the combination therapy led to more myelinated axons, as shown by electron microscopy. These data suggest that this strategy significantly protected transplanted NSCs via the anti-inflammation and anti-apoptosis effects of etanercept, promoting re-myelination, neural regeneration and locomotor function.