Neuroscience
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Dopamine (DA) neurons in the midbrain are crucial for motivational control of behavior. However, recent studies suggest that signals transmitted by DA neurons are heterogeneous. This may reflect a wide range of inputs to DA neurons, but which signals are provided by which brain areas is still unclear. ⋯ Most reward-related signals were positively biased: excitation and inhibition when a better and worse reward was expected, respectively. These PPTg neurons tended to retain the reward value signal until after a reward outcome, representing 'value state'; this was different from DA neurons which show phasic signals representing 'value change'. Our data, together with previous studies, suggest that PPTg neurons send positive reward-related signals mainly to the medial-central SNc where DA neurons encode motivational values, and sensorimotor/arousal signals to the lateral SNc where DA neurons encode motivational salience.
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We have studied the performance of a spatial reference memory task, the navigation strategy and the changes in the cytochrome c oxidase activity (COx) in different brain regions in exercised (forced exercise, 10 consecutive days, 15min/day) and non-exercised adult Wistar rats. The spatial learning task was carried out in the radial-arm water maze (RAWM) for four days with six daily trials, and on the fifth day, a probe session was run, in which we rotated the position of the distal cues 90° in a clockwise direction. During the four days of training, the exercised group showed shorter latency and distance traveled to find the platform, as well as fewer memory errors and reduced use of non-appropriate navigation strategies according to the protocol of the task (egocentric). ⋯ Finally, higher COx activity in the cingulate and the retrosplenial cortices, as well as in the dorsal CA1 and CA3 was found in the exercised group. All in all, it seems that the exercise favored the configuration of an efficient and accurate cognitive map of the environment, which was supported by our finding that the rotation of the cues, without altering their overall configuration, did not affect performance. The brain regions with higher COx activity in the exercised group seem to be involved in this function.
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Work from the past 40years has unraveled a wealth of information on the cellular and molecular mechanisms underlying synaptic plasticity and their relevance in physiological brain function. At the same time, it has been recognized that a broad range of neurological diseases may be accompanied by severe alterations in synaptic plasticity, i.e., 'maladaptive synaptic plasticity', which could initiate and sustain the remodeling of neuronal networks under pathological conditions. ⋯ This review focuses on recent experimental evidence, which highlights the fundamental role of endoplasmic reticulum-mediated Ca(2+) signals in modulating the duration, direction, extent and type of synaptic plasticity. We discuss the possibility that intracellular Ca(2+) stores may regulate synaptic plasticity and hence behavioral and cognitive functions at the interface between physiology and pathology.
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Physical activity has been demonstrated to diminish age-related brain volume shrinkage in several brain regions accompanied by a reduction of age-related decline in cognitive functions. Most studies investigated the impact of cardiovascular fitness or training. Other types of fitness or training are less well investigated. ⋯ Additionally, a moderating effect of the volume of the basal ganglia (as a whole, but also separately for putamen and globus pallidus) on the relationship between motor fitness and executive function was revealed. Coordination training increased caudate and globus pallidus volume. We provide evidence that coordinative exercise seems to be a favorable leisure activity for older adults that has the potential to improve volume of the basal ganglia.
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Empathy for pain, a widely studied sub-form of empathy, is an ability to recognize and share the pain of others. It involves brain regions associated with the emotional component of pain. Recent studies found that emotional pain could be modulated by stimulating the dorsolateral prefrontal cortex (DLPFC) with transcranial direct current stimulation (tDCS). ⋯ It was found that ratings for others' pain increased in subjects with an anodal tDCS of the DLPFC in comparison to those with sham tDCS, indicating enhanced pain empathy with the anodal tDCS. Furthermore, the changes of ratings for others' pain were positively correlated with the changes of pain-related self-unpleasantness. These findings indicate that tDCS could modulate pain empathy and be used as a potential tool for modulating diseases accompanied with empathy deficits.