Abstract :
Keywords Visual WM; Attention; Retro-cue; Alpha oscillations Highlights * The role of alpha power during WM maintenance was examined using a retro-cue paradigm. * Retro-cue contrast was manipulated in a block design to induce different visual attentional demands. * The expectance of different retro-cue contrasts did not modulate alpha power in the delay period preceding the cue. * Delay alpha activity might be related to internal processing demands and not to sensory gatekeeping. Abstract It has been proposed that alpha oscillations reflect the endogenous modulation of visual cortex excitability. In particular, alpha power increases during the maintenance period in Working Memory (WM) tasks have been interpreted as a mechanism to avoid potential interference of incoming stimuli. In this study we tested whether alpha power was modulated during the maintenance of WM to enhance the processing of relevant incoming perceptual stimuli. To this aim, we manipulated the contrast of a stimulus presented during the maintenance period of a WM task. The to-be-detected stimulus could indicate which of the encoded representations was going to be probed after the delay (spatial retro-cue) or could signal that all the representations had equal probability to be tested (neutral retro-cue). Time-frequency analysis revealed that alpha power preceding retro-cue presentation was not differently modulated by the two different contrast conditions. This is, participants did not endogenously modulate alpha oscillations upon low perceptual contrast stimuli incoming. These results suggest that alpha delay activity is not a goal directed mechanism to control the inflow of information during WM maintenance. Instead, current data suggest that alpha delayed activity might be an index of increased allocation of attentional resources to the processing of the WM representations. Author Affiliation: (a) Departamento de Psicología Experimental, Procesos Cognitivos y Logopedia, Universidad Complutense de Madrid, Madrid, Spain (b) Departamento de Psicología Básica, Universidad Autónoma de Madrid, Madrid, Spain (c) Departamento de Psicología Biológica y de la Salud, Universidad Autónoma de Madrid, Madrid, Spain (d) Instituto Pluridisciplinar, Universidad Complutense de Madrid, Madrid, Spain (e) Centro de Investigación Nebrija en Cognición (CINC), Universidad Nebrija, Madrid, Spain (f) Departamento de Educación, Universidad Nebrija, Madrid, Spain * Correspondence to: Universidad Nebrija, C. de Sta. Cruz de Marcenado, 27, 28015 Madrid, Spain. Article History: Received 15 March 2022; Revised 9 June 2022; Accepted 15 July 2022 Byline: Joaquín Macedo-Pascual (a), Pablo Campo (b), Almudena Capilla (c), José Antonio Hinojosa (a,d,e), Claudia Poch [cpoch@nebrija.es] (f,*)