Neuroscience letters
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Neuroscience letters · Jul 2011
Increased short latency afferent inhibition after anodal transcranial direct current stimulation.
Transcranial direct current stimulation (tDCS), a technique for central neuromodulation, has been recently proposed as possible treatment in several neurological and psychiatric diseases. Although shifts on focal brain excitability have been proposed to explain the clinical effects of tDCS, how tDCS-induced functional changes influence cortical interneurones is still largely unknown. The assessment of short latency afferent inhibition (SLAI) of motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS), provides the opportunity to test non-invasively interneuronal cholinergic circuits in the human motor cortex. ⋯ Whereas RMT and the amplitude of unconditioned MEPs did not change after anodal tDCS, SLAI significantly increased. In conclusion, anodal tDCS-induced effects depend also on the modulation of cortical interneuronal circuits. The enhancement of cortical cholinergic activity assessed by SLAI could be an important mechanism explaining anodal tDCS action in several pathological conditions.
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Neuroscience letters · Jul 2011
Mobilization of circulating endothelial progenitor cells after endovascular therapy for ruptured cerebral aneurysms.
Emerging evidence shows that circulating endothelial progenitor cells (EPCs) promote regeneration of the endothelium at sites of vessel injury. This study was designed to test the hypothesis that EPCs are mobilized in patients who had ruptured cerebral aneurysm (CA) and underwent endovascular therapy. Fourteen patients with ruptured CAs were recruited and blood samples were analyzed after coil embolization surgery. ⋯ The levels of plasma VEGF and platelet counts also significantly increased in parallel with the increase in EPCs, leading to significant positive correlations of circulating EPCs with VEGF in plasma (r=0.636, P<0.01) and platelet counts (r=0.721, P<0.001), respectively. The finding suggests that EPCs are mobilized upon surgery and may play a critical role in repairing injured vascular endothelium. Levels of EPCs in peripheral blood could also serve as a prognostic marker for the outcomes of ruptured cerebral aneurysms after surgical repair.
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Neuroscience letters · Jul 2011
Minocycline injection in the ventral posterolateral thalamus reverses microglial reactivity and thermal hyperalgesia secondary to sciatic neuropathy.
We hypothesized that microglia in the ventral posterolateral (VPL) nucleus of the thalamus are reactive following peripheral nerve injury, and that inhibition of microglia by minocycline injection in the VPL attenuates thermal hyperalgesia. Our results show increased expression of OX-42 co-localized with phosphorylated p38MAPK (P-p38) in the VPL seven days after chronic constriction injury (CCI) of the sciatic nerve. ⋯ Minocycline abrogates the increased expression of OX-42 in the VPL after CCI. Therefore, peripheral nerve injury favors a hyperactive microglial phenotype in the VPL, suggesting remote neuroimmune signaling from the damaged nerve to the brain, concomitant with neuropathic behavior that is reversed by local intervention in the VPL to inhibit microglia.
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Neuroscience letters · Jul 2011
Perception to laser heat stimuli in depressed patients is reduced to Aδ- and selective C-fiber stimulation.
Depression and clinical pain have been shown being strongly associated with each other. However, recent studies have demonstrated that depressed patients are less sensitive to experimental pain than healthy individuals. Reasons for this phenomenon are still elusive. ⋯ They also failed significantly more often to recognize the noxious laser-heat stimuli. Thus, higher pain thresholds to experimental stimuli in depressed patients are not only associated with reduced perception of cutaneous Aδ-, but also with decreased perception of selective C-fiber input. The physiological underpinnings of the phenomenon remain elusive and should be examined in the future to understand whether it is based on changes in the periphery or in central processing or both.
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Neuroscience letters · Jul 2011
Semantic integration of differently asynchronous audio-visual information in videos of real-world events in cognitive processing: an ERP study.
In the real world, some of the auditory and visual information received by the human brain are temporally asynchronous. How is such information integrated in cognitive processing in the brain? In this paper, we aimed to study the semantic integration of differently asynchronous audio-visual information in cognitive processing using ERP (event-related potential) method. Subjects were presented with videos of real world events, in which the auditory and visual information are temporally asynchronous. ⋯ When the sound was prior to the critical action, a larger late positive wave was observed under the incongruous condition compared to congruous condition. P600 might represent a reanalysis process, in which the mismatch between the critical action and the preceding sound was evaluated. It is shown that environmental sound may affect the cognitive processing of a visual event.