Neuroscience
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The rat has long been considered an important model system for studying neural mechanisms of auditory perception and learning, and particularly mechanisms involving auditory thalamo-cortical processing. However, the functional topography of the auditory thalamus, or medial geniculate body (MGB) has not yet been fully characterized in the rat, and the anatomically-defined features of field-specific, layer-specific and tonotopic thalamo-cortical projections have never been confirmed electrophysiologically. ⋯ We also demonstrated that microstimulation in the MGv elicited cortical activation in layer-specific, region-specific and tonotopically organized manners. To our knowledge, the present study has provided the first and most compelling electrophysiological confirmation of the anatomical organization of the primary thalamo-cortical pathway in the rat, setting the groundwork for further investigation.
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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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Gender Differences of Peripheral Plasma and Liver Metabolic Profiling in APP/PS1 Transgenic AD mice.
Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive impairment. Currently, there is less knowledge of the involvement of the peripheral biofluid/organ in AD, compared with the central nervous system. In addition, with reported high morbidity in women in particular, it has become very important to explore whether gender difference in the peripheral metabolome is associated with AD. ⋯ Disturbances in AD male mice were milder with depletion of monounsaturated fatty acids. We also observed a higher activity of delta-6-desaturate and suppressed activity of delta-5-desaturate in female mice, whereas inhibited stearoyl-CoA-desaturase in male mice suggested that AD induced by the double mutant genes results in different fatty acids catabolism depending on gender. Our results provide metabolic clues into the peripheral biofluid/organs involved in AD, and we propose that a gender-specific scheme for AD treatment in men and women may be required.
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Adult hippocampal neurogenesis can be modulated by various physiological and pathological conditions, including stress, affective disorders, and several neurological conditions. Given the proposed role of this form of structural plasticity in the functioning of the hippocampus (namely learning and memory and affective behaviors), it is believed that alterations in hippocampal neurogenesis might underlie some of the behavioral deficits associated with these psychiatric and neurological conditions. Thus, the search for compounds that can reverse these deficits with minimal side effects has become a recognized priority. ⋯ Based on these results, we recommend that future neurogenesis studies that require repeated handling and manipulation of animals should include a naïve (non-manipulated) control to determine the baseline levels of hippocampal cell proliferation and neuronal differentiation. Overall, these findings demonstrate that Isx-9 is a promising synthetic compound for the mitigation of stress-induced deficits in adult hippocampal neurogenesis. Future studies are thus warranted to evaluate the pro-neurogenic properties of Isx-9 in animal models of affective and neurological disorders associated with impaired hippocampal structural plasticity.