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Julie Bolduc-Teasdale, Michelle Beaupré, Nicolas Robitaille, Michelle McKerral; ERP ‘blink’ instructions revisited: Effects on attention-related processes. Journal of Vision 2007;7(9):187. doi: 10.1167/7.9.187.
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© ARVO (1962-2015); The Authors (2016-present)
An important challenge for researchers working with electrophysiological measures is the reduction of ocular artifacts and more specifically, the blinking phenomenon. Despite the fact that most experiments include a “do not blink” instruction in their protocol, very few studies have investigated its impact on cerebral activity, and more precisely on attention-related processes. Although previous studies have shown that, when given, the instruction leads to a reduction in amplitude of the P3b during a two-stimulus oddball paradigm, methodological weaknesses could be responsible for the observed results. Therefore the current study aimed to reevaluate the effect of the “do not blink” instruction on the P3b while counterbalancing conditions between two groups of subjects for whom two experimental conditions (1- “do not blink” instruction; 2- no blink instruction) were presented in different order. The paradigm used was a modified three-stimulus oddball task which enabled us to not only look at the P3b, but also at the P3a wave, which has been interpreted as an orientation of the attention response. The use of this P3a-evoking paradigm consequently adds to the novelty of the current study. While no effect was detected regarding the P3b, a significant decrease in P3a amplitude was observed in the first group during the second experimental bloc. This group received the ‘no ‘blink instruction’ condition prior to the “do not blink” instruction condition. However an opposite effect was observed for the second group for whom the P3a amplitude also decreased during the second bloc, this time the ‘no blink instruction’ condition. Thus, contrary to previous studies implying that the instruction altered or reduced the attentional resources available to perform the task at hand, the results obtained in the present study rather suggest the presence of a task-related habituation effect.
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