Time and Numbers, or the when and where of attentional processing:A psychophysiological approach using the SSVEP

Abstract

Our brain can process and selectively attend to many relevant components in our environment simultaneously. Although our knowledge on how does this happens is quite extensive, there is still a long path to go to understand each of the cognitive and biological components of attentional processing, and how our brain makes them work together. Here I presented the results of studies addressing questions regarding the physiological aspects involved in number processing and allocation of spatial attention, and implemented a novel technique for analyzing the Steady state visual evoked potentials (SSVEP) recordings for studying temporal attention. I provided important evidence for the implementation of SSVEP to study temporal attention. Temporal attention-modulation effects were observe for flickering stimuli in the alpha-band frequency for the fundamental and the second harmonic, supporting the hypothesis that alpha is part of the neurophysiological substrate of temporal attention. The studies involving numbers and their role in spatial attention provided physiological evidence for the effect of numbers in spatial attention when they are part of the task, and inconclusive evidence was obtained for the role of numbers in spatial attention when they are not relevant for the task. Extending the use of SSVEP as has been shown in this thesis will provide further evidence to elucidate the specific mechanisms involved in entrainment of ongoing oscillations induced by different external sources (e.g., rhythmic stimuli and rhythmic time intervals) with the internal rhythms (e.g. endogenous attention), to have a more comprehensive understating of this interaction and its effects on behavior