Neuroscience letters
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Neuroscience letters · Feb 2012
Volumetric variation in subregions of the cerebellum correlates with working memory performance.
We aimed to investigate the relationship between structural variations in the cerebellum and individual differences in working memory performance as assessed by average reaction time (RT) and correction rate (CR) on a 3-back task. High-resolution T1-weighted magnetic resonance images were acquired in 311 healthy young adults. ⋯ These findings suggest that RT on a working memory task is related to structural variation in both motor and cognitive subregions of the cerebellum, while CR is mainly associated with the cognitive subregions. Our findings provide further evidence that the cerebellum contributes to working memory function.
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Neuroscience letters · Jan 2012
Sensory feedback prosthesis reduces phantom limb pain: proof of a principle.
Constrained functionality and phantom limb pain (PLP) are major concerns for forearm amputees. Neuroscientific investigations of PLP suggest that behaviorally relevant stimulation of the stump can decrease PLP. Furthermore the prosthesis user could use feedback information of the prosthesis hand for optimizing prosthesis motor control when handling soft and fragile objects. Somatosensory feedback information from a prosthetic hand may therefore help to improve prosthesis functionality and reduce phantom limb pain. ⋯ A prosthesis with a feedback function appears to be a promising therapeutic tool to reduce phantom limb pain and to increase functionality in everyday tasks. Future studies should further investigate the scope of application of that principle.
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Neuroscience letters · Jan 2012
Tapentadol increases levels of noradrenaline in the rat spinal cord as measured by in vivo microdialysis.
Spinal noradrenaline is thought to play an important role in descending pain inhibitory pathways and the modulation of nociceptive information at the spinal level. Tapentadol is a μ-opioid receptor (MOR) agonist and noradrenaline reuptake inhibitor (NRI). We showed previously that tapentadol, in contrast to morphine, elevates levels of noradrenaline, but not serotonin, in the ventral hippocampus of rats. ⋯ In contrast to tapentadol and venlafaxine, morphine slightly decreased levels of noradrenaline and serotonin. This study demonstrates that analgesic doses of tapentadol (and venlafaxine), but not morphine, increase spinal noradrenaline levels and that tapentadol is devoid of a relevant serotonergic effect. It supports the suggestion that the NRI component of tapentadol is functionally relevant and contributes to its mechanism of action.
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Neuroscience letters · Jan 2012
mTOR activates hypoxia-inducible factor-1α and inhibits neuronal apoptosis in the developing rat brain during the early phase after hypoxia-ischemia.
The mammalian target of rapamycin (mTOR) exerts neuroprotective effects under hypoxic or ischemic conditions. To explore whether mTOR participates in neuroprotective signaling through regulation of hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and neuronal apoptosis in developing rat brain with hypoxia-ischemia (HI), we operated on postnatal day 10 rats by ligating the common carotid artery followed by exposure to systemic hypoxia. Brains were collected at various intervals to detect the expression of mTOR, phosphorylated mTOR (p-mTOR), HIF-1α, VEGF and cleaved caspase 3 (CC3), using immunohistochemistry and Western blot analysis. ⋯ Furthermore, pretreatment with rapamycin, a mTOR specific inhibitor, significantly inhibited HIF-1α and VEGF protein after HI. The expression of CC3 and the number of TUNEL-positive cells were up-regulated at 8h and down-regulated at 24h after HI in the rapamycin-treated group. Our findings suggest that mTOR may participate in the regulation of HIF-1α, VEGF and neuronal apoptosis, serving neuroprotective functions after HI in developing rat brain.
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Neuroscience letters · Jan 2012
Counteracting roles of metabotropic glutamate receptor subtypes 1 and 5 in regulation of pain-related spatial and temporal synaptic plasticity in rat entorhinal-hippocampal pathways.
It was previously found that persistent inflammatory pain state resulted in enhancement of synaptic connections and efficacy in direct entorhinal-hippocampal (EC-HIP) pathways. In the current study, the roles of two subtypes of group I metabotropic glutamate receptors in the above processes were evaluated. Similarly, pain-related spatial and temporal synaptic enhancement model was stably achieved by the multi-electrode array (8×8) recordings in the hippocampal slices of rats pre-treated with intraplantar (i.pl.) bee venom (BV) injection. ⋯ However, the BV-enhanced LTP was significantly suppressed by antagonism of mGluR5 with MPEP. Neither of the two drugs affected magnitude of LTP in rats treated by i.pl. saline. Taken together with our previous results, it is suggested that mGluR1 be involved in tonic inhibition of EC-HIP synaptic enhancement, while mGluR5 be involved in maintenance of persistent inflammatory pain-associated EC-HIP synaptic enhancement that is largely based upon activation of ionic glutamate receptors.