Neuroscience
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Randomized Controlled Trial
Transcranial direct current stimulation (tDCS) over the right dorsolateral prefrontal cortex affects stimulus conflict but not response conflict.
When the human brain encounters a conflict, performance is often impaired. Two tasks that are widely used to induce and measure conflict-related interference are the Eriksen flanker task, whereby the visual target stimulus is flanked by congruent or incongruent distractors, and the Simon task, where the location of the required spatial response is either congruent or incongruent with the location of the target stimulus. Interestingly, both tasks share the characteristic of inducing response conflict but only the flanker task induces stimulus conflict. ⋯ The results indicate that cathodal tDCS over the right DLPFC increased the flanker interference effect while having no impact on the Simon effect. This finding provides empirical support for the role of the right DLPFC in stimulus-stimulus rather than stimulus-response conflict, which suggests the existence of multiple, domain-specific control mechanisms underlying conflict resolution. In addition, methodologically, the study also demonstrates the way in which brain stimulation techniques can reveal subtle yet important differences between experimental paradigms that are often assumed to tap into a single process.
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Randomized Controlled Trial
No role of beta receptors in cognitive flexibility: Evidence from a task-switching paradigm in a randomized controlled trial.
There is evidence that noradrenergic coeruleo-cortical projections are involved in different forms of cognitive flexibility. So far, no studies in humans have investigated the involvement of beta receptors on task-switching performance, a well-established measure of cognitive flexibility. ⋯ The acute administration of propranolol did not affect the size of switching costs compared to the intake of the neutral placebo. Our results, corroborated by Bayesian inference, suggest that beta receptors do not modulate cognitive flexibility as measured by task-switching performance.
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Randomized Controlled Trial
An eight month randomized controlled exercise intervention alters resting state synchrony in overweight children.
Children with low aerobic fitness have altered brain function compared to higher-fit children. This study examined the effect of an 8-month exercise intervention on resting state synchrony. Twenty-two sedentary, overweight (body mass index ≥85th percentile) children 8-11 years old were randomly assigned to one of two after-school programs: aerobic exercise (n=13) or sedentary attention control (n=9). ⋯ The default mode, cognitive control, and motor networks showed more spatial refinement over time in the exercise group compared to controls. The motor network showed increased synchrony in the exercise group with the right medial frontal gyrus compared to controls. Exercise behavior may enhance brain development in children.
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Randomized Controlled Trial
Parkinson's disease patients show impaired corrective grasp control and eye-hand coupling when reaching to grasp virtual objects.
The effect of Parkinson's disease (PD) on hand-eye coordination and corrective response control during reach-to-grasp tasks remains unclear. Moderately impaired PD patients (n=9) and age-matched controls (n=12) reached to and grasped a virtual rectangular object, with haptic feedback provided to the thumb and index fingertip by two 3-degree of freedom manipulanda. The object rotated unexpectedly on a minority of trials, requiring subjects to adjust their grasp aperture. ⋯ Strikingly, PD patients tracked their hands with their gaze, and their movements became destabilized when having to make online corrective responses to object perturbations exhibiting pauses and changes in movement direction. These impairments largely remained even when tested in the ON state, despite significant improvement on the Unified Parkinson's Disease Rating Scale. Our findings suggest that basal ganglia-cortical loops are essential for mediating eye-hand coordination and adaptive online responses for reach-to-grasp movements, and that restoration of tonic levels of dopamine may not be adequate to remediate this coordinative nature of basal ganglia-modulated function.
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Randomized Controlled Trial
Plant-derived nanoparticle treatment with cocc 30c ameliorates attention and motor abilities in sleep-deprived rats.
Sleep is an essential physiological process that underlies crucial cognitive functions as well as emotional reactivity. Thus, sleep deprivation (SD) may exert various deleterious effects. In this study, we aimed to examine the adverse behavioral and hormonal effects of SD and a potential treatment with Plant-derived nanoparticle treatment - cocc 30c. ⋯ Likewise, SD led to increased levels of corticosterone and serotonin while decreasing testosterone and leptin. Interestingly, cocc 30c treatment has moderated these hormonal alterations. We conclude that the treatment with cocc 30c recovers both short-term behavioral and the long-term hormonal modulations following SD.