Neuroscience
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Guess who's coming to dinner: Brain signatures of racially biased and politically correct behaviors.
The ability to share feelings with those of someone in pain is affected by the racial difference between the target and the onlooker. A differential empathic activation for race (DEAR effect) in favor of in-group members has been documented in the brain pain matrix. However, we are also capable of unbiased responses that manifest politically correct behaviors toward people of a different race. ⋯ On the other hand, during the response phase a significant out-group specific DEAR effect emerged in the prefrontal cortices. This latter effect was coupled with a revealing behavioral pattern: while the magnitude of the painful experience attributed to Caucasians and Africans was the same, our participants were significantly slower when judging the pain experience of the African actors. We propose a model that logically integrates these two contrasting forces at the neurobiological and behavioral level.
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Sigma receptor (σR), a unique receptor family, is classified into three subtypes: σR1, σR2 and σR3. It was previously shown that σR1 activation induced by 1μM SKF10047 (SKF) suppressed N-methyl-d-aspartate (NMDA) receptor-mediated responses of rat retinal ganglion cells (GCs) and the suppression was mediated by a distinct Ca(2+)-dependent phospholipase C (PLC)-protein kinase C (PKC) pathway. In the present work, using whole-cell patch-clamp techniques in rat retinal slice preparations, we further demonstrate that SKF of higher dosage (50μM) significantly suppressed AMPA receptor (AMPAR)-mediated light-evoked excitatory postsynaptic currents (L-EPSCs) of retinal ON-type GCs (ON GCs), and the effect was reversed by the σR1 antagonist BD1047, suggesting the involvement of σR1. ⋯ Calcium imaging further revealed that SKF (50μM) did not change intracellular calcium concentration in GCs and persisted to suppress L-EPSCs when intracellular calcium was chelated by BAPTA. The SKF (50μM) effect was intact when protein kinase A (PKA) and phosphatidylinostiol (PI)-PLC signaling pathways were both blocked. We conclude that the SKF (50μM) effect is Ca(2+)-independent, PKG-dependent, but not involving PKA, PI-PLC pathways.
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Abacus-based mental calculation (AMC) activates the frontoparietal areas largely overlapping with the working memory (WM) network. Given the critical role of WM in cognition, how to improve WM capability has attracted intensive attention in past years. However, it is still unclear whether WM could be enhanced by AMC training. ⋯ In addition, the n-back task-induced activations in the right frontoparietal circuitry and left occipitotemporal junction (OTJ) declined as a result of training. Notably, the decreases in activity were positively correlated with performance gains across trained participants. These results suggest AMC training not only improves calculating skills but also have the potential to promote individuals' WM capabilities, which is associated with the functional plasticity of the common neural substrates.
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In an attempt to improve current understanding of risk factors that influence individual susceptibility to poor outcomes following mild traumatic brain injury (mTBI) or concussion, this project investigated whether modifications to paternal experiences (Advanced Age (AA) or High-Fat Diet (HFD)) affected offspring susceptibility to behavioral symptomology and changes in gene expression following pediatric concussion in a rodent model. The study demonstrated that paternal treatment prior to conception altered behavioral outcomes and molecular characterization of offspring. Offspring of AA fathers demonstrated abnormal behavioral performance when compared to offspring of control fathers. ⋯ Additionally, this study provided insight into the mechanisms that mediate non-genetic paternal inheritance. Paternal treatment and the mTBI significantly influenced expression of a majority of the genes under examination in the prefrontal cortex, hippocampus, and nucleus accumbens, with changes being dependent upon sex and the brain region examined. These epigenetic changes may have contributed to the differences in offspring susceptibility to concussion.
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The dorsomedial striatum (DMS) has been implicated in the acquisition of reward representations, a proposal leading to the hypothesis that it should play a role in situations involving reward loss. We report the results of an experiment in which the effects of DMS excitotoxic lesions were tested in consummatory successive negative contrast (reward devaluation), autoshaping training with partial vs. continuous reinforcement (reward uncertainty), and appetitive extinction (reward omission). Animals with DMS lesions exhibited reduced lever pressing responding, but enhanced goal entries, during partial reinforcement training in autoshaping. ⋯ Thus, DMS lesions selectively affected the behavioral adjustment to a situation involving reward uncertainty, producing a behavioral reorganization according to which goal tracking (goal entries) became predominant at the expense of sign tracking (lever pressing). This pattern of results shows that the function of the DMS in situations involving reward loss is not general, but restricted to reward uncertainty. We suggest that a nonassociative, drive-related process induced by reward uncertainty requires normal output from DMS neurons.