Neuroscience letters
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Neuroscience letters · Oct 2011
Association between suicide attempt and a tri-allelic functional polymorphism in serotonin transporter gene promoter in Chinese patients with schizophrenia.
Mounting evidence supports the association between a polymorphism in the serotonin transporter gene promoter region (5-HTTLPR) and suicidal behaviour. Recently, a novel variant of the 5-HTTLPR L allele was identified. The previously unknown L(G) allele produced similar levels of gene expression to the S allele and might have been misclassified as a "high-expression" allele in previous association studies. ⋯ These findings differ from those reported in Caucasian subjects, where no associations have been reported. Different genetic backgrounds may give rise to different allelic distribution, causing differential effects on the expression of endophenotypes of suicide behaviours. Although the potential influence of multiple comparisons might weaken our findings, our study provides preliminary evidence for a potentially gender-specific role of a "high-expression" 5-HTTLPR polymorphism in susceptibility to suicide in Chinese patients with schizophrenia.
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The rubber hand illusion (RHI) occurs when a person misattributes a fake hand as his or her own hand. Previously, the RHI has been examined with both the rubber hand and the participant's real hand uncrossed with regards to the participant's midline. The present study examined the strength of the illusion when the real hand, the fake hand or both hands are placed across the body midline. ⋯ In contrast, no RHI was present when either hand was crossed over the midline. Additionally, a shift in hand judgment towards the midline was observed when participants crossed their real hand. These results indicate the importance of the midline in understanding representations of the body.
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Neuroscience letters · Oct 2011
Comparative StudyAlterations in neuronal survival and glial reactions after axotomy by ceftriaxone and minocycline in the mouse hypoglossal nucleus.
Some antibiotics are suggested to exert neuroprotective effects via regulation of glial responses. Attenuation of microglial activation by minocycline prevents neuronal death in a variety of experimental models for neurological diseases, such as cerebral ischemia, Parkinson's and Huntington's disease. Ceftriaxone delays loss of neurons in genetic animal models of amyotrophic lateral sclerosis through upregulation of astrocytic glutamate transporter expression (GLT-1). ⋯ The cellular densities of microglia at D28 were significantly lower in minocycline-treated mice than in saline-treated mice. The time course analysis showed that immediate increase in microglia at D3 and D7 was not suppressed by minocycline. The present observations show that minocycline and ceftriaxone promote survival of lesioned motoneurons in the mouse hypoglossal nucleus, and also suggest that alterations in glial responses might be involved in neuroprotective actions of antibiotics.
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Neuroscience letters · Oct 2011
Activation of group II metabotropic glutamate receptors induces long-term depression of excitatory synaptic transmission in the substantia nigra pars reticulata.
Activation of group II metabotropic glutamate receptors (mGlu2 and mGlu3) has been implicated as a potential therapeutic strategy for treating both motor symptoms and progressive neurodegeneration in Parkinson's disease (PD). Modulation of excitatory transmission in the basal ganglia represents a possible mechanism by which group II mGlu agonists could exert antiparkinsonian effects. Previous studies have identified reversible effects of mGlu2/3 activation on excitatory transmission at various synapses in the basal ganglia, including the excitatory synapse between the subthalamic nucleus (STN) and the substantia nigra pars reticulata (SNr). ⋯ To determine the relative contributions of mGlu2 and mGlu3 to the LTD induced by LY379268, we tested the ability of LY379268 (100nM) to induce LTD in wild type mice and mice lacking mGlu2 or mGlu3. LY379268 induced similar LTD in wild type mice and mGlu3 knockout mice, whereas LTD was absent in mGlu2 knockout mice, indicating that mGlu2 activation is necessary for the induction of LTD in the SNr. These studies suggest a novel role for mGlu2 in the long-term regulation of excitatory transmission in the SNr and invite further exploration of mGlu2 as a therapeutic target for treating the motor symptoms of PD.
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Neuroscience letters · Oct 2011
Comparative StudyAging-related changes in the default mode network and its anti-correlated networks: a resting-state fMRI study.
Intrinsic brain activity in a resting state incorporates components of the task negative network called default mode network (DMN) and task-positive networks called attentional networks. In the present study, the reciprocal neuronal networks in the elder group were compared with the young group to investigate the differences of the intrinsic brain activity using a method of temporal correlation analysis based on seed regions of posterior cingulate cortex (PCC) and ventromedial prefrontal cortex (vmPFC). ⋯ The decreased coactivations in the DMN network components and their negative networks in the old group may reflect age-related alterations in various brain functions such as attention, motor control and inhibition modulation in cognitive processing. These alterations in the resting state anti-correlative networks could provide neuronal substrates for the aging brain.