Neuroscience
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Comparative Study
Masking Differentially Affects Envelope-following Responses in Young and Aged Animals.
Age-related hearing decline typically includes threshold shifts as well as reduced wave I auditory brainstem response (ABR) amplitudes due to cochlear synaptopathy/neuropathy, which may compromise precise coding of suprathreshold speech envelopes. This is supported by findings with older listeners, who have difficulties in envelope and speech processing, especially in noise. However, separating the effects of threshold elevation, synaptopathy, and degradation by noise on physiological representations may be difficult. ⋯ High-pass noise may affect EFR amplitudes in young animals more than aged by reducing the contributions of high-frequency-sensitive inputs. EFRs to SAM tones in modulated noise (NAM) suggest that neurons of young animals can synchronize to NAM at lower sound levels and maintain dual AM representations better than older animals. The overall results show that EFR amplitudes are strongly influenced by aging and the presence of a competing sound that likely reduces or shifts the pool of responsive neurons.
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In this study, fused electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) techniques were utilized to examine the relationship between the ERP (event-related potential) component P300 and fNIRS hemodynamic signals for high-accuracy deception detection. During the performance of a modified concealed information test (CIT) task, a series of Chinese names were presented, which served as the target, irrelevant, or the probe stimuli for both the guilty and innocent groups. For participants in the guilty group, the probe stimulus was their individual name, whereas for the innocent group, the probe stimulus was one irrelevant name. ⋯ Interestingly, we discovered that for the guilty group, the probe stimulus elicited significantly higher P300 amplitude at parietal site and also evoked significantly stronger oxyhemoglobin (HbO) concentration changes in the bilateral superior frontal gyrus and bilateral middle frontal gyrus than the irrelevant stimuli. However, this is not the case for the innocent group, in which participants exhibited no significant differences in both ERP and fNIRS measures between the probe and irrelevant stimuli. More importantly, our findings also demonstrated that the combined ERP and fNIRS feature was able to differentiate the guilty and innocent groups with enhanced sensitivity, in which AUC (the area under Receiver Operating Characteristic curve) is 0.94 for deception detection based on the combined indicator, much higher than that based on the ERP component P300 only (0.85) or HbO measure only (0.84).
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The Engrailed-2 (En2) gene codes for a homeobox-containing transcription factor, involved in midbrain-hindbrain embryonic development. In postnatal brain, En2 is expressed in the ventral mesencephalon, cerebellum, hippocampus and neocortex. Two single-nucleotide polymorphisms (SNPs) that are associated to autism spectrum disorders (ASD) have been identified in the human EN2 gene. ⋯ As compared to En2+/+ NSCs, En2-/- NSCs derived from basal ganglia show impaired GABAergic differentiation accompanied by a reduced expression of the BDNF receptor trkB. Conversely, En2-/- NSCs derived from the neocortex expressed high levels of trkB and readily differentiated into neurons, as En2+/+ NSCs. Our results suggest that En2 contributes to GABAergic neuron differentiation from basal ganglia NSCs through a trkB-dependent BDNF signaling, thus providing a possible explanation for the reduced number of GABAergic interneurons detected in the En2-/- postnatal forebrain.
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Pregnancy is accompanied by complex biological adaptations, including extreme hormonal fluctuations. Moreover, changes on the endocrine level are accompanied by changes in cerebral anatomy, such as reductions in brain or gray matter volume. Since declining brain and tissue volumes are characteristic for normal aging, the question arises of whether such pregnancy-induced anatomical effects are permanent or transient. ⋯ Comparing the BrainAGE indices between both time points, female brains at late postpartum were estimated to be considerably younger than at early postpartum. On average, that difference was about five years (mean ± SD: 5.4 ± 2.4 years). These findings suggest a substantial restoration/rejuvenation effect after giving birth, which is evident already within the first couple of months.
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In DRG an increase in miR-133b-3p, miR-143-3p, and miR-1-3p correlates with the lack of development of neuropathic pain following a peripheral nerve injury. Using lentiviral (LV) vectors we found that a single injection of LV-miR-133b-3p or LV-miR-143-3p immediately after a peripheral nerve injury prevented the development of sustained mechanical and cold allodynia. Injection of LV-miR-133b-3p or LV-miR-143-3p by themselves or in combination, on day 3 post-injury produced a partial and transient reduction in mechanical allodynia and a sustained decrease in cold allodynia. ⋯ LV-miR133b-3p and LV-miR-143-3p reduced TRPM8-mRNA. LV-miR-133b-3p and LV-miR-143-3p prevent the development of chronic pain when injected immediately after the injury, but are only partially effective when injected at later times. LV-miR-1a-3p had no effect on pain, but complemented the actions of LV-miR-133b-3p or LV-miR-143-3p resulting in a sustained reversal of pain when co-injected 3 days following nerve injury.