Accurate face processing skills are pivotal for typical social cognition, and impairments in this ability characterise various clinical conditions (e.g., prosopagnosia). No study to date has investigated whether transcranial direct current stimulation (tDCS) can causally enhance face processing. In addition, the category-and the process-specificity of tDCS effects, as well as the role of the timing of neuromodulation with respect to the execution of cognitive tasks are still unknown. In this single-blind, sham-controlled study, we examined whether the administration of anodal-tDCS (a-tDCS) over the right occipital cortex of healthy volunteers (N = 64) enhances performance on perceptual and memory tasks involving both face and object stimuli. Neuromodulation was delivered in two conditions: online (a-tDCS during task execution) and offline (a-tDCS before task execution). The results demonstrate that offline atDCS enhances the perception and memory performance of both faces and objects. There was no effect of online a-tDCS on behaviour. Furthermore, the offline effect was site-specific since a-tDCS over the sensory-motor cortex did not lead to behavioural changes. Our results add relevant information about the breadth of cognitive processes and visual stimuli that can be modulated by tDCS, and about the design of effective neuromodulation protocols, which have implications for advancing theories in cognitive neuroscience and clinical applications.

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SummaryIn the presence of H 2 O 2 , heme proteins form active intermediates, which are able to oxidize exogenous molecules. Often these products are not stable compounds but reactive species on their own, such as organic radicals. They can both diffuse to the bulk of the solution or react with the protein that generated them. Here, we describe the self-modification underwent by heme proteins with globin-type fold, that is, myoglobin, hemoglobin, and neuroglobin when treated with NO 2 2 or catechols in the presence of H 2 O 2 . The reactive nitrogen species generated by NO 2 2 give rise to nitration, oxidation, and/or crosslinking reactions between the proteins or their subunits. The quinones formed upon reaction with catechols easily modify Cys and His residues and eventually cause protein aggregation, which induces precipitation. The pattern of modifications undergone by the protein strongly depends on the nature of the protein and the reaction conditions. IUBMBIUBMB Life, 60(1): [41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] 2008