Neuroscience
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Anorexia nervosa (AN) is a psychiatric illness characterized by restricted eating and an intense fear of gaining weight. Most individuals with AN are females, diagnosed first during adolescence, 40-80% of whom exhibit excessive exercise, and an equally high number with a history of anxiety disorder. We sought to determine the cellular basis for individual differences in AN vulnerability by using an animal model, activity-based anorexia (ABA), that is induced by combining food restriction (FR) with access to a running wheel that allows voluntary exercise. ⋯ This negative correlation is evident within 2days of FR, before body weight loss approaches life-threatening levels for any individual. These findings suggest that increased shunting inhibition by α4βδ-GABAARs in spines of CA1 pyramidal neurons may participate in the protection against the ABA-inducing environmental factors of severe weight loss by suppressing excitability of the CA1 pyramidal neurons which, in turn, is related indirectly to suppression of excessive exercise. The data also indicate that, although exercise has many health benefits, it can be maladaptive to individuals with low levels of α4βδ-GABAARs in the CA1, particularly when combined with FR.
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High molecular weight (HMW) glycosaminoglycanes of the extracellular matrix have been implicated in tissue repair. The aim of this study was to evaluate if small synthetic hyaluronan disaccharides with different degrees of sulfation (methyl 2-acetamido-2-deoxy-3-O-(β-d-glucopyranosyluronic acid)-O-sulfo-α-d-glucopyranoside, sodium salt (di0S), methyl 2-acetamido-2-deoxy-3-O-(β-d-glucopyranosyluronic acid)-6-di-O-sulfo-α-d-glucopyranoside, disodium salt (di6S) and methyl 2-acetamido-2-deoxy-3-O-(β-d-glucopyranosyluronic acid)-4,6-di-O-sulfo-α-d-glucopyranoside, trisodium salt (di4,6S)) could improve cell survival in in vitro and in vivo brain ischemia-related models. Rat hippocampal slices subjected to oxygen and glucose deprivation and a photothrombotic stroke model in mice were used. ⋯ In conclusion, di4,6S affords neuroprotection in in vitro and in vivo models of ischemic neuronal damage. Our results suggest that its neuroprotective effect could be exerted through its capability to reduce oxidative stress during ischemia. Its small molecular size makes it a more potential druggable drug to target the brain as compared with its HMW parent compound hyaluronan.
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Throughout human history, economic bubbles have formed and burst. As a bubble grows, microeconomic behavior ceases to be constrained by realistic predictions. This contradicts the basic assumption of economics that agents have rational expectations. ⋯ A functional connectivity analysis showed that the connectivity between the DLPFC and the IPL was predominant compared with other connectivities only during the bubble. These findings indicate that uncertain and unstable market conditions changed brain modes in traders. These brain mechanisms might lead to a loss of control caused by wishful thinking, and to microeconomic bubbles that expand, on the macroscopic scale, toward bust.
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Self-worth is particularly influenced by self-appraisal, which is negatively biased in many psychiatric disorders. Positive and negative self-appraisals also shape current emotional states or even evoke defensive reactions, when they are incongruent with a subject's current state. Prior studies have mainly used externally given evaluative appraisals. ⋯ Positive self-appraisal had no effect on the perception of a photo of oneself, whereas negative appraisal increased activity in the anterior insula and parietal regions. Overall, positive self-appraisal activated more emotion-related brain regions, whereas negative self-appraisal had a relatively stronger influence on perception-related brain activity. These findings could on the one hand explain the effect of negative self-appraisal on the behavior in the real world and on the other hand support a stronger focus of psychotherapy on enhancing positive self-appraisals.
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The present study tested whether and how motor experience with a specific tool affects motor representation of a specific movement. To this aim, we considered a group of expert tennis players and a control group of athletic individuals without tennis experience. Participants were asked to execute 20 single forehands into the wall with a tennis racket (movement execution - ME) and, afterward, to produce a kinesthetic image of themselves while executing the same movements (motor imagery - MI). ⋯ On the opposite, the handled tool did not modulate MI performances of the control group. In conclusion, this study showed that motor representation of subjects who developed motor skills associated to tool-use is reliant on the object used to practice movements. This finding suggests that, although MI mainly relies on the activity of cortical motor regions, non-motor information - as the use of the tool to practice movement - strongly affects the MI performance.