Neuroscience
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Functional magnetic resonance imaging (fMRI) is a convolution of latent neural activity and the hemodynamic response function (HRF). According to prior studies, the neurodegenerative process in idiopathic Parkinson's Disease (PD) interacts significantly with neuromuscular abnormalities. Although these underlying neuromuscular changes might influence the temporal characteristics of HRF and fMRI signals, relatively few studies have explored this possibility. ⋯ The results suggested that neglecting HRF variability may cultivate false-positive and false-negative FC group differences. Furthermore, HRF was related to dopamine receptor type 2 (DRD2) gene expression (P < 0.001, t = -7.06, false discover rate-corrected). Taken together, these findings reveal HRF variation and its possible underlying molecular mechanism in PD, and suggest that deconvolution could reduce the impact of HRF variation on FC group differences.
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Numerous blood oxygenation level-dependent (BOLD) imaging studies have shown that generalized anxiety disorder (GAD) can lead to abnormal activation of specific brain regions in patients. However, these methods lack sufficient temporal resolution to explain the underlying brain dynamics of GAD. The electroencephalogram (EEG) microstate allows us to explore brain dynamics at the subsecond level. ⋯ The optimal configuration combined the spatial features of source-level data with microstate features and achieved the highest classification accuracy. Collectively, the statistical results indicated remarkable differences in dynamic brain parameters between the two groups, and patients with GAD may have abnormalities in their higher sensory cortex that affect the processing of anxiety signals. Furthermore, our proposed fusion framework provides a reliable method for GAD automatic detection.
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The glymphatic system is a fluid-clearance pathway that clears cerebral waste products, and its dysfunction has been associated with protein aggregation diseases such as Alzheimer's disease. To understand how the glymphatic system changes with aging, we enrolled 433 cognitive unimpaired participants (236 women and 197 men, 13-88 years) and evaluated the glymphatic function by calculating diffusion tensor imaging analysis along the perivascular space (ALPS) index and explored how the ALPS index is associated with cortical atrophy and cognitive decline in older people. ⋯ Declines in mental manipulation and short-term memory performance in the older participants were associated with a lower ALPS index and cortical atrophy in the amygdala, anterior and posterior cingulate, thalamus and middle frontal regions. Our findings highlight that the ALPS index could be used to evaluate brain reserve and cognitive reserve in older people.
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Peripheral nerve injury (PNI) induces severe functional loss in extremities. Progressive denervation and atrophy occur in the muscles if the nerve repair is delayed for long periods of the time. To overcome these difficulties, detailed mechanisms should be determined for neuromuscular junction (NMJ) degeneration in target muscles after PNI and regeneration after nerve repair. ⋯ In addition, NMJ- and Schwann cell-related molecules showed high expression in the target muscle in the allograft model. These results suggest that Schwann cell migrating from the allograft might play a crucial role in nerve regeneration in the chronic phase after PNI. The relationship between the NMJ and Schwann cells should be further investigated in the target muscle.
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The nucleus accumbens (NAc) is considered an interface between motivation and action, with NAc neurons playing an important role in promoting reward approach. However, the encoding by NAc neurons that contributes to this role remains unknown. We recorded 62 NAc neurons in male Wistar rats (n = 5) running towards rewarded locations in an 8-arm radial maze. ⋯ Together, these neurons accounted for most of the speed and acceleration encoding identified in our analysis. In contrast, a further 16% of neurons presented a valley during acceleration followed by a peak just prior to or after reaching reward (deceleration-on cells). These findings suggest that these three classes of NAc neurons influence the time course of speed changes during locomotor approach to reward.