Neuroscience
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Down syndrome (DS), trisomy of human chromosome 21 (Hsa21), is the most common genetic cause of intellectual disability (ID). There are no treatments for the cognitive deficits. The Ts65Dn is a partial trisomy mouse model of DS that shows learning and memory (LM) impairments and other abnormalities relevant to those seen in DS. ⋯ Superimposing protein data onto the molecular pathway defining long-term potentiation (LTP) shows that profiles are consistent with both abnormal LTP in vehicle-treated Ts65Dn and its observed rescue by RO4938581. Lastly, comparing these results with those from Ts65Dn treated, using a different protocol, with the NMDA receptor antagonist, memantine, that also rescues LM impairments, identifies common and divergent responses to the two drugs. Expansion of this approach to include additional drugs and DS models would aid in determining critical protein abnormalities and in identifying cocktails of drugs and/or new drug targets that would be effective in clinical trials for ID in DS.
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The main goal of this paper is to introduce the concept of iso-perceptual manifold for perception of body configuration and related variables (kinesthetic perception) and to discuss its relation to the equilibrium-point hypothesis and the concepts of reference coordinate and uncontrolled manifold. Hierarchical control of action is postulated with abundant transformations between sets of spatial reference coordinates for salient effectors at different levels. ⋯ Some combinations of afferent and efferent signals, in particular those implying a violation of body's integrity, give rise to variable percepts by artificial projection onto iso-perceptual manifolds. This framework is used to interpret unusual features of vibration-induced kinesthetic illusions and to predict new illusions not yet reported in the literature.
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Understanding neuroadaptations involved in obesity is critical for developing new approaches to treatment. Diet-induced neuroadaptations within the dorsal striatum have the capacity to drive excessive food seeking and consumption. Five-week-old C57BL/6J mice consumed a high-fat, high-sugar 'western diet' (WD) or a control 'standard diet' (SD) for 16 weeks. ⋯ Neuronal excitability and GABAergic transmission were unaffected by diet in either striatal subregion. Our results demonstrate that a high-fat, high-sugar diet alters facets of glutamate, dopamine, and opioid signaling within the dorsal striatum, with some subregion specificity. These alterations within a brain area known to play a role in food motivation/consumption and habitual behavior are highly relevant for the clinical condition of obesity and its treatment.
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Both spinal cord infiltrating CD4+ T lymphocytes and microglial CD40 contribute to the maintenance of neuropathic pain-like behaviors induced by spinal nerve L5 transection (L5Tx), a murine model of neuropathic pain. Here, we sought to investigate the involvement of multiple chemokines in microglial CD40-mediated and CD4+ T lymphocytes-mediated L5Tx-induced sensory hypersensitivity. Spinal cord chemokine expression in CD4 knockout (KO), CD40 KO, and wild type (WT) BALB/c mice was determined at the protein level via multiplex assays and at the RNA level via quantitative real-time PCR. ⋯ Intrathecal administration of CXCL1 in WT mice significantly reduced L5Tx-induced mechanical hypersensitivity. CD40 KO mice also displayed higher levels of Ly6G (neutrophil marker) RNA expression in the lumbar spinal cord post-L5Tx. Altogether, our data suggest that CD4+ T lymphocytes and microglial CD40 mediate their pro-nociceptive effects in part by promoting selected chemokine responses, and more importantly, CXCL1 can play an anti-nociceptive role in peripheral nerve injury-induced neuropathic pain, which is possibly mediated by infiltrating neutrophils.