Neuroscience
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Cognitive deficit remains an intractable symptom of schizophrenia, accounting for substantial disability. Despite this, little is known about the cause of cognitive dysfunction in schizophrenia. Recent studies suggest that schizophrenia patients show several changes in dentate gyrus structure and functional characteristic of immaturity. ⋯ Additionally, CaMKIIα-hKO mice showed spontaneous bursts of spike wave activity, possibly indicating absence seizures. The GABAB agonist baclofen increased, while the GABAB antagonist CGP35348 and the T-Type Ca2+ channel blocker Ethosuximide decreased spike wave burst frequency. None of these changes in event-related potentials or EEG oscillations are characteristic of those observed in general population of patients with schizophrenia; yet, CaMKIIα-hKO mice likely model a subpopulation of patients with schizophrenia.
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Accumulating evidence indicates that repetitive transcranial magnetic stimulation (rTMS) ameliorates motor symptoms in patients with Parkinson's disease (PD); however, patients' responses to rTMS are different. Here, we aimed to explore neural activity changes in patients with PD exhibiting different responses to high-frequency rTMS treatments using functional magnetic resonance imaging (fMRI). We treated 24 patients with PD using 10-session rTMS (10 Hz) over the supplementary motor area (SMA) for 10 days. ⋯ We identified increased fALFF values in the left Crus II of the cerebellar hemisphere and bilateral thalamus as responsive signs to rTMS. Furthermore, the motor response to rTMS over the SMA, measured by the reduction in UPDRS-III and bradykinesia scores, was positively associated with increased fALFF values in the left Crus2 of cerebellar hemisphere, left lobule VIIB of cerebellar hemisphere, right lobule VI of the cerebellar hemisphere, and the right postcentral gyrus. These findings provide evidence for the involvement of cerebellar activity in the motor response to rTMS treatment.
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The pineal gland is a key player in surveillance and defense responses. In healthy conditions, nocturnal circulating melatonin (MEL) impairs the rolling and adhesion of leukocytes to the endothelial layer. Fungi, bacteria, and pro-inflammatory cytokines block nocturnal pineal MEL synthesis, facilitating leukocyte migration to injured areas. ⋯ There was an increase in cortical and no change in cerebellar MEL. These effects were mediated by changes in the expression of coding genes to synthetic and metabolizing melatonergic enzymes. Thus, the pineal gland plays a role as a first-line structure to respond to the death of cells inside the brain by turning NAS into the darkness hormone.
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Dopamine facilitates approach to reward via its actions on dopamine receptors in the nucleus accumbens. For example, blocking either D1 or D2 dopamine receptors in the accumbens reduces the proportion of reward-predictive cues to which rats respond with cued approach. Recent evidence indicates that accumbens dopamine also promotes wakefulness and arousal, but the relationship between dopamine's roles in arousal and reward seeking remains unexplored. ⋯ Haloperidol reduced spontaneous locomotion but did not increase sleep postures, instead increasing immobility in non-sleep postures. We place these results in the context of the extensive literature on dopamine's contributions to behavior, and propose the arousal-motor hypothesis. This novel synthesis, which proposes that two main functions of dopamine are to promote arousal and facilitate motor behavior, accounts both for our findings and many previous behavioral observations that have led to disparate and conflicting conclusions.
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An intrinsic characteristic of the motor system is the preference of one side of the body. Lateralization is found in motor behavior and in the structural and functional correlates of cortical motor networks. While genetic factors have been elucidated as mechanisms leading to such asymmetries, findings in motor learning and experience from clinical experience demonstrate considerable additional plasticity during the lifespan. ⋯ Importantly, areas of maximum activation were not identical with areas showing the strongest associations with performance improvement. These data suggest that learning a complex bimanual motor skill is associated with a shift of theta-band oscillations to the left in central-parietal areas. The relationship with performance improvement may reflect increased cortical efficiency of task-relevant processing.