Neuroscience
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Learning a motor skill requires physical practice that engages neural networks involved in movement. These networks have also been found to be engaged during perception of sensory signals associated with actions. ⋯ Relatively few studies examined neural plasticity induced by perception and its role in transfer of motor knowledge. Here, we review this body of literature and point to future directions for the development of alternative, physiologically grounded ways in which sensory signals could be harnessed to improve motor skills.
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Psychosocial factors such as anxiety, depression and catastrophizing, commonly associated with established chronic pain, also may be associated with an increased risk of chronic postsurgical pain (CPSP) when present preoperatively. We used a repeat social defeat (RSD) paradigm to induce psychosocial stress in rodents prior to incisional surgery of the paw. Mixed effects growth curve models were utilized to examine resolution of mechanical hypersensitivity in rats for four weeks following surgery. ⋯ Prior exposure to RSD significantly increased microglial activation and neuronal sensitization (pERK-IR) within the ipsilateral spinal cord. In conclusion, we found that chronic social stress alters the neurobiological response to surgical injury, resulting in slowed recovery. This model maybe useful for future interventional studies examining the mechanistic interactions between depression and risk of CPSP.
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A major regulatory task of the organism is to keep brain functions relatively constant in spite of metabolic changes (e.g., hunger vs. satiety) or availability of energy (e.g., glucose administration). Resting-state functional magnetic resonance imaging (rs-fMRI) can reveal resulting changes in brain function but previous studies have focused mostly on the hypothalamus. Therefore, we took a whole-brain approach and examined 24 healthy normal-weight men once after 36 h of fasting and once in a satiated state (six meals over the course of 36 h). ⋯ This interaction was driven by a fALFF increase after glucose treatment in the hunger relative to the satiety condition. Our results indicate that fALFF analysis is the most sensitive measure to detect effects of metabolic states on resting-state brain activity. Moreover, we show that multimethod rs-fMRI provides an unbiased approach to identify spontaneous brain activity associated with changes in homeostasis and caloric intake.
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Clinical patients in a vegetative state or unresponsive wakefulness syndrome (VS/UWS) demonstrate distinct arousal-awareness dissociation; the neuropathological mechanisms underlying such dissociation remain poorly understood. Here, we systematically examined how functional connectivity from the brainstem areas regulating arousal to the cortical networks supporting internal and external awareness is disrupted in minimally conscious state (MCS) and VS/UWS patients. Resting-state functional imaging was conducted in 23 MCS patients, 31 VS/UWS patients, and 20 age-matched healthy individuals. ⋯ We show that functional connectivity from the PTA and caudal midbrain area to the cortical-awareness-supporting networks were significantly reduced in MCS and VS/UWS patients; importantly, as the clinical symptoms of consciousness disorders deepen from MCS to VS/UWS, functional connectivity strength became significantly reduced, changing from presenting no significant connections in MCS to widespread negative connections in VS/UWS. Additionally, we observed increased connectivity from the PTA and caudal midbrain area to limbic structures, the brainstem areas, and the cerebellum in MCS and VS/UWS patients, consistent with prior studies. These findings offer important insights into the neural network mechanisms underlying the long-observed arousal-awareness dissociation in VS/UWS patients and provide additional neuroimaging-based biomarkers for the clinical diagnosis of MCS and VS/UWS patients.