Neuroscience
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Deficits in the anticipation and experience of affective events represent a key risky factor for a variety of mental disorders, such as anxiety and depression. Here, we examined temporal dynamics underlying the modulations of the aversive mood state on neural responses of anticipating and perceiving affective pictures. Participants were asked to perform an affective cueing paradigm in both threat and safe contexts. ⋯ Our findings revealed that threat context compared with the safe context attenuated the contingent negative variation (CNV) responses to the cues of positive expressions, and decreased differential late positive potential (LPP) responses to the perception of negative and positive events. These findings suggest that aversive mood dampens the anticipation of positive events and inhibits the elaboration of negative events. The current findings do not only advance our understanding on the temporal characteristics of affective anticipation and experience but also have implications on the emotional deficits across various mental disorders characterized by chronic mood disturbances.
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Auto-regulation mechanisms in serotonergic neurons regulate their electrical activity and secretion. Since these neurons release serotonin from different structural compartments - including presynaptic terminals, soma, axons and dendrites - through different mechanisms, autoregulation mechanisms are also likely to be different at each compartment. Here we show that a chloride-mediated auto-inhibitory mechanism is exclusively localized at presynaptic terminals, but not at extrasynaptic release sites, in serotonergic Retzius neurons of the leech. ⋯ This shows that the auto-inhibition effects are unique to nerve terminals. We further determined that serotonin released from peri-synaptic dense-core vesicles contributes to auto-inhibition in the terminals, since blockade of L-type calcium channels, which are required to stimulate extrasynaptic but not synaptic release, decreased the amplitude of the auto-inhibition response. Our results show that the auto-regulation mechanism at presynaptic terminals is unique and different from that described in the soma of these neurons, further highlighting the differences in the mechanisms regulating serotonin release from different neuronal compartments, which expand the possibilities of a single neuron to perform multiple functions in the nervous system.
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Increasing evidence has indicated that long non-coding RNAs (lncRNAs) play a vital role for adjusting RNA transcripts as competing endogenous RNAs (ceRNAs) for microRNAs (miRNAs). The present study was intended to explore the probable regulation of lncRNA TALNEC2 in ischemic stroke. In this study, we measured the up-regulation of TALNEC2 and down-regulation of miR-650 in mice brains after cerebral ischemia/reperfusion (I/R) operation and in cultured neuroblastoma cells of neuro-2A (N2a) treated with oxygen glucose deprivation/reoxygenation (OGD/R). ⋯ In result, overexpression of TALNEC2 antagonized the inhibition impact of miR-650 on APAF1 expression and N2a cell apoptosis induced by OGD/R, while TALNEC2 knockdown aggravated the impact. Furthermore, TALNEC2 knockdown reversed brain injury and neurological deficits induced by I/R in vivo. In conclusion, we verified a TALNEC2/miR-650/APAF1 signaling pathway as a key mechanism monitoring cerebral I/R injury.
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The N170 is a large deflection of the human electroencephalogram (EEG), peaking at about 170 milliseconds over the occipito-temporal cortex after the sudden onset of a face stimulus. The N170 reflects perceptual awareness of a face and its onset corresponds to the emergence of reliable face-selectivity in the human brain. However, whether sensitivity to the long-term familiarity of a face identity emerges already at this early time-point remains debated. ⋯ This effect is especially present for personally familiar faces, learned in natural conditions. In the human brain, effects linked to familiarity with specific facial identities therefore appear to emerge between 150 and 200 ms in occipito-temporal brain regions, i.e., shortly after the onset of face-selectivity but at the same time as the earliest high-level effects of immediate unfamiliar face identity repetition. This observation challenges standard neurocognitive models with a clear-cut distinction between perceptual and memory stages in human face recognition.
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Crucial to an animal's movement through their environment and to the maintenance of their homeostatic physiology is the integration of sensory information. This is achieved by axons communicating from organs, muscle spindles and skin that connect to the sensory ganglia composing the peripheral nervous system (PNS), enabling organisms to collect an ever-constant flow of sensations and relay it to the spinal cord. ⋯ This review covers the origins and development of the DRG and the cells that populate it, and focuses on how sensory connectivity to the spinal cord is achieved by the diverse developmental and molecular processes that control axon guidance in the trunk sensory system. We also describe convergences and differences in sensory neuron formation among different vertebrate species to gain insight into underlying developmental mechanisms.