Neuroscience
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Previous studies often report that early auditory deprivation or congenital deafness contributes to cross-modal reorganization in the auditory-deprived cortex, and this cross-modal reorganization limits clinical benefit from cochlear prosthetics. However, there are inconsistencies among study results on cortical reorganization in those subjects with long-term unilateral sensorineural hearing loss (USNHL). It is also unclear whether there exists a similar cross-modal plasticity of the auditory cortex for acquired monaural deafness and early or congenital deafness. ⋯ Our results indicate that the left primary auditory cortex (non-auditory-deprived cortex) in patients with left USNHL has been reorganized by visual and sensorimotor modalities through cross-modal plasticity. Furthermore, the cross-modal reorganization also alters the directional brain functional networks. The auditory deprivation from the left or right side generates different influences on the human brain.
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In the spinal dorsal horn (DH), nerve injury activates microglia and induces neuropathic pain. Several studies clarified an involvement of adenosine triphosphate (ATP) in the microglial activation. However, the origin of ATP together with the release mechanism is unclear. ⋯ Injection of the adenovirus encoding mCherry-LAMP1 into DRG showed that mCherry-positive lysosomes are transported to the central nerve terminal in DH. These findings suggest that activation of lysosome synthesis including ATP packaging in DRG, the central transportation of the lysosome, and subsequent its exocytosis from the central nerve terminal of DRG neurons in response to nerve injury could be a partial mechanism for activation of microglia in DH. This lysosome-mediated microglia activation mechanism may provide another clue to control nociception and pain.
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Task switching is our ability to abandon an old, irrelevant task in order to perform a new, more relevant one. Data from neuropsychology and neuroimaging studies indicate hemispheric asymmetries in task switching, however the neural mechanisms subtending switching, and in particular protocols to improve switching abilities are yet to be established. The present study aimed to assess hemispheric asymmetry and practice effects in task switching by using transcranial direct current stimulation (tDCS). ⋯ The task was repeated three times in three separate sessions in order to test practice effects with and without stimulation. Results show that increased hemispheric asymmetry in dorsolateral prefrontal areas improved switching performance as measured by a better practice effect, compared to sham condition. Our results support the hypothesis of dynamic hemispheric asymmetry in task switching and reinforce the notion of utilizing brain stimulation with traditional training methods in order to enhance cognitive abilities.
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Beta-arrestins (β-arrs) are initially known as negative regulators of G protein-coupled receptors (GPCRs). Recently, there is increasing evidence suggesting that β-arrs also serve as scaffolds and adapters that mediate distinct intracellular signal transduction initiated by GPCR activation. In the previous study, we have shown that metabotropic glutamate receptor 7 (mGluR7) and extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling may be involved in the developmental sevoflurane neurotoxicity. ⋯ For the behavior study, treatment with LAP4 or AMN082 significantly improved the emotional and spatial learning and memory disorders induced by postnatal sevoflurane exposure. These results suggested that β-arr1 and 2 may differently modulate mGluR7 signaling in developmental sevoflurane neurotoxicity. This study also reveals a β-arr-biased agonism at GPCRs (e.g. mGluR7).
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The sudden interruption of the increase of the concentration of the gamma-aminobutyric acid (GABA), determines an increase in neuronal activity. GABA withdrawal (GW) is a heuristic analogy, with withdrawal symptoms developed by other GABA receptor-agonists such as alcohol, benzodiazepines, and neurosteroids. ⋯ GW induces pre- and postsynaptic changes: a decrease in GABA synthesis/release, and the decrease in the expression and composition of GABAA receptors associated with increased calcium entry into the cell. GW is an excellent bioassay for studying partial epilepsy, epilepsy refractory to drug treatment, and a model to reverse or prevent the generation of abstinences from different drugs.