Neuroscience
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Kainate receptors (KARs) are glutamate receptors with ionotropic and metabotropic activity composed of the GluK1-GluK5 subunits. We previously reported that KARs modulate excitatory and inhibitory transmission in the olfactory bulb (OB). Zinc, which is highly concentrated in the OB, also appears to modulate OB synaptic transmission via actions at other ionotropic glutamate receptors (i.e., AMPA, NMDA). ⋯ It is also of potential importance given our previously reported molecular data suggesting that OB neurons express relatively high levels of GluK1 and GluK2. Our present findings suggest that a physiologically relevant concentration of zinc modulates KARs expressed by M/T cells. As M/T cells are targets of zinc-containing olfactory sensory neurons, synaptically released zinc may influence odor information-encoding synaptic circuits in the OB via actions at KARs.
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The specific mechanism of migraine chronification remains unclear. We previously demonstrated that synaptic plasticity was associated with migraine chronification. EphB receptors and their ligands, ephrinBs, are considered to be key molecules regulating the synaptic plasticity of the central nervous system. ⋯ The administration of EphB1-Fc relieved hyperalgesia and changes in synaptic plasticity induced by CM. In addition, EphB1-Fc inhibited the upregulation of NR2B phosphorylation. These results indicate that ephrinB/EphB signaling may regulate synaptic plasticity in CM via NR2B phosphorylation, which suggests the novel idea that ephrinB/EphB signaling may be a target for the treatment of migraine chronification.
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Unilateral auditory deprivation results in lateralization changes in the central auditory system, interfering with the integration of binaural information and thereby leading to a decrease in binaural auditory functions such as sound localization. Principal neurons of the lateral superior olive (LSO) are responsible for computing the interaural intensity differences that are critical for sound localization in the horizontal plane. ⋯ Furthermore, by analysing the miniature inhibitory postsynaptic currents and miniature excitatory postsynaptic currents, we found that unilateral auditory deprivation weakened the inhibitory driving force on the intact side, whereas it strengthened the excitatory driving force on the ablated side. In summary, asymmetric changes in the electrophysiological activity of LSO principal neurons were found on both sides at postnatal day 19, one week after unilateral cochlear ablation.
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Early life experiences play a vital role in contributing to healthy brain development. Adverse experiences have a lasting impact on the prefrontal cortex (PFC) and basolateral amygdala (BLA), brain regions associated with emotion regulation. Early life adversity via maternal separation (MS) has sex-specific effects on expression of parvalbumin (PV), which is expressed in fast-spiking GABAergic interneurons that are preferentially enwrapped by perineuronal nets (PNNs). ⋯ Our results confirm past reports that PFC PNNs form gradually throughout development; however, PNN density plateaus in adolescence, while intensity continues to increase into adulthood. Importantly, MS delays PNN formation in the prelimbic PFC and results in sex-specific aberrations in PNN structural integrity that do not appear until adulthood. The present findings reveal sex-, age-, and region-specific effects of early life adversity on PNN and PV maturation, implicating neuroplastic alterations following early life adversity that may be associated with sex differences in psychopathology and resilience.
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Whole-body movements are performed daily, and humans must constantly take into account the inherent instability of a standing posture. At times these movements may be performed in risky environments and when facing different costs of failure. The aim of the study was to test the hypothesis that in upright stance participants continuously estimate both probability of failure and cost of failure such that their postural responses will be based on these estimates. ⋯ Results showed also that the participants' estimates of the probability of failure accounted for their own inherent instability. Moreover, participants showed a tendency to overweight large probabilities of failure with more biomechanically constrained standing postures that results in suboptimal estimates of risky environments. Overall, our results suggest that participants tune their standing postural responses by empirically estimating the cost of failure and the uncertainty level in order to minimize the risk of falling when cost is high.