Neuroscience
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Action observation can facilitate motor skill learning and lead to a memory trace in motor representations of action. However, it remains unclear whether the action itself or the goal of the action drive changes in motor representations after learning by observation. ⋯ In contrast, observing a sequence of visual cue positions devoid of hand action increases motor cortical excitability in both hemispheres and facilitates motor skill learning in the right hand (Experiment 1) and left hand for a mirror-symmetric sequence (Experiment 2). We propose that the encoding of observed movements maps onto motor representations of the same action to form a limb-specific motor memory, whereas the learning of spatial goals forms memory traces in the motor representations in both hemispheres to prepare for potential action in either hand.
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We have previously shown how the Frontal Pole cortex (FPC) neurons play a unique role in both the monitoring and evaluating of self-generated decisions during feedback in a visually cued strategy task. For each trial of this task, a cue instructed one of two strategies: to either stay with the previous goal or shift to the alternative goal. Each cue was followed by a delay period, then each choice was followed by a feedback. ⋯ This supports the involvement of goal-selective cells in the evaluation of self-generated decisions at the feedback time. We also observed a dynamic change of the correlations in time, indicating that the connections among cell-assemblies were transient, changing between internal states at the feedback time. These results indicate that the changing of the pattern of neural correlations can underlie the flexibility of the prefrontal computations.
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Although numerous studies have shown that brain regions around the intraparietal sulcus play an important role in general mathematical or numerical processing, little is known about the specific neural correlates for processing mathematical principles. In the present study, we compared the activation intensity, multi-voxel activation patterns, and functional connectivity (FC) related to processing mathematical principles (including arithmetic and logic) with those related to arithmetic. Twenty right-handed undergraduates (10 male; aged 18-25 years) participated in the study. ⋯ Results from the univariate, multi-voxel, and functional connectivity analyses consistently revealed that the left angular gyrus, left middle temporal gyrus, and left inferior frontal gyrus were more involved in the processing of mathematical principles than in computation. These regions are connected with the intraparietal sulcus, the core region involved in mathematical processing. As the AG, MTG and orbital part of IFG were key regions of the semantic system, these results provide direct evidence for a crucial role of the semantic system in the processing of mathematical principles.
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Stroke is one of the major leading causes of death and disability worldwide, and post-stroke cognitive impairment is a major contributor to this disability. Astragaloside IV (AST-IV) is a primary bioactive compound of Radix Astragali, which is widely used in traditional Chinese medicine to treat stroke. AST-IV was found to possess cognition-enhancing properties against ischemic stroke; however, the mechanisms underlying this effect remain largely elusive. ⋯ AST-IV significantly enhanced PKA and CREB phosphorylation and prevented OGD-induced mitochondrial dysfunction, thereby protecting neurons exposed to OGD from injury and death. Furthermore, the effects of AST-IV were partially blocked by a PKA inhibitor. Collectively, these data elucidated the molecular mechanisms underlying the protective effects of AST-IV against ischemic injury in cortical neurons.
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Adolescent binge drinking renders young drinkers vulnerable to alcohol use disorders in adulthood; therefore, understanding alcohol-induced brain damage and associated cognitive dysfunctions is of paramount importance. Here we investigated the effects of binge-like adolescent intermittent ethanol (AIE) exposure on nonspatial working memory, behavioral flexibility and cholinergic alterations in the nucleus accumbens (NAc) in male and female rats. On postnatal days P25-57 rats were intubated with water or ethanol (at a dose of 5 g/kg) on a 2-day-on/2-day-off cycle and were then tested in adulthood on social recognition and probabilistic reversal learning tasks. ⋯ During probabilistic reversal learning, AIE-treated male and female rats showed behavioral inflexibility as indicated by a higher number of trials needed to complete three reversals within a session, longer response latencies for lever selection, and for males, a higher number of errors as compared to water-treated rats. AIE exposure also reduced the number of cholinergic interneurons in the NAc in males and females. These findings indicate AIE-related pathologies of accumbal cholinergic interneurons and long lasting cognitive-behavioral deficits, which may be associated with cortico-striatal hypofunction.