Neuroscience
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Randomized Controlled Trial
Effects of Nicotine on Task Switching and Distraction in Non-smokers. An fMRI Study.
Nicotine improves sustained attention and reduces distractor interference, promoting cognitive stability. While stable performance may be beneficial in some situations, others require flexible updating of task demands. Frontoparietal networks, basal ganglia and thalamus contribute to an optimal balance of stable and flexible performance. ⋯ However, a brain-behaviour correlation analysis revealed that the nicotine-induced alterations of distractor costs correlated positively with distractor-related neural activity in the right intraparietal sulcus and the right pulvinar nucleus of the thalamus. We suggest that a nicotinic contribution to balancing stability and flexibility is weak in young healthy non-smokers. The brain-behaviour correlations imply that if nicotine reduces distractor interference, the modulation is found in thalamic-parietal networks.
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Randomized Controlled Trial
Domain-specific involvement of the posterior parietal cortex in attention network and attentional control of ADHD: A randomized, cross-over, sham-controlled tDCS study.
Transcranial direct current stimulation (tDCS) has been increasingly used in attention-deficit hyperactivity disorder (ADHD) with mixed results. Previous tDCS studies merely targeted the dorsolateral prefrontal cortex and right inferior frontal gyrus with partial or no improving effects on cognitive deficits respectively. Posterior parietal cortex is another region involved in attentional functioning of ADHD, however, its contribution to ADHD attention functions has not been explored in tDCS studies. ⋯ No significant effect on shifting attention and response inhibition was found. Our findings indicate a domain-specific involvement of the r-PPC in attention orienting network of ADHD children. Activation of the r-PPC improves bottom-up but hinders top-down attentional control suggesting a critical role of the r-PPC in ADHD bottom-up attentional control.