Neuroscience
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Early life stress may lead to lifelong impairments in psychophysiological functions, including emotional and reward systems. Unpredicted decrease in reward magnitude generates a negative emotional state (frustration) that may be involved with susceptibility to psychiatric disorders. We evaluated, in adolescents and adult rats of both sexes, whether maternal separation (MS) alters the ability to cope with an unexpected reduction of reward later in life. ⋯ MS females and adolescents did not differ from controls. We concluded that MS enhances the response to frustration in adult males. The change in the ratio of GluN2A and GluN2B subunits in dHC could be related to a stronger, more difficult to update memory of the aversive experience.
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Past self-report and cognitive-behavioural studies of the effects of transcranial direct current stimulation (tDCS) targeting the medial prefrontal cortex (mPFC) on semantic self-referential processing (SRP) have yielded mixed results. Meanwhile, electroencephalography (EEG) studies show that alpha oscillation (8-12 Hz) may be involved during both semantic and somatic SRP, although the effect of tDCS on alpha-EEG during SRP remains unknown. ⋯ Our results suggest that while mPFC-tDCS may be insufficient to alter immediate subjective experience during SRP, mPFC-tDCS may modulate the power and functional connectivity of the brain's alpha oscillations during somatic SRP. Future research directions are discussed.
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It is increasingly evident that structural and functional changes in brain regions associated with obsessive-compulsive disorder (OCD) are often related to the development of the disease. However, limited research has been conducted on how the progression of OCD may lead to an imbalance between goal-directed and habit-learning systems. This study employs resting-state functional imaging to examine the relationship between illness duration and abnormal brain function in goal-directed/habitual-learning systems. ⋯ Additionally, abnormal brain activity is associated with illness duration, and the abnormalities observed in goal-directed regions are more effective in distinguishing different courses of OCD patients. Patients with different durations of OCD have functional abnormalities in the goal-directed and habitual-learning brain regions. There are differences in the degree of abnormality in different brain regions, and these abnormalities may disrupt the balance between goal-directed and habitual-learning systems, leading to increasing reliance on repetitive behaviors.
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Decision-making is a cognitive process, in which participants need to attend to relevant information and ignore the irrelevant information. Previous studies have described a set of cortical areas important for attention. It is unclear whether subcortical areas also serve a role. ⋯ We found that decreased neural activities in STN were associated with sustained attention. By examining connectivity across STN and various sub-regions of the prefrontal cortex (PFC), we found that decreased connectivity across areas was associated with sustained attention. Our results indicated that decreased STN activities were associated with sustained attention, and the STN-PFC circuit supported this process.
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Stress during adolescence clearly impacts brain development and function. Sex differences in adolescent stress-induced or exacerbated emotional and metabolic vulnerabilities could be due to sex-distinct gene expression in hypothalamic, limbic, and prefrontal brain regions. However, adolescent stress-induced whole-genome expression changes in key subregions of these brain regions were unclear. ⋯ Canonical pathways reflected well-known sex-distinct maladies and diseases, substantiating the therapeutic potential of the DE genes found in the current study. Thus, we proposed specific sex distinct, adolescent stress-induced transcriptional changes found in the current study as examples of the molecular bases for sex differences witnessed in stress induced or exacerbated emotional and metabolic disorders. Future behavioral studies and single-cell studies are warranted to test the implications of the DE genes identified in this study in sex-distinct stress-induced susceptibilities.