The role of alpha rhythm in sensory input control during selective attention

• Applicant: Professor Dr. Matthias M. Müller
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: from 2017 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 385480795

The ultimate goal of the present project is to investigate the neural systems that control selective attention, in particular the temporal dynamics of the interaction between EEG alpha oscillations, early visual processing and post-stimulus processing in higher cortical areas. To this end, we dissect these mechanisms by looking at the interactions between alpha EEG modulation, sensory gain control, and event-related potentials in the visual pathways. During the first tenure of the grant we employed a classical Posner type spatial attention design and found no correlation between alpha oscillations and steady state visual evoked potentials (SSVEPs), a marker of early visual processing. Further, we conducted three visual search experiments, in which we found the to-be-expected alpha desynchronization and increase of SSVEP amplitudes along with an N2pc for target stimuli. Interestingly, although distractor stimuli elicited a Pd, a marker for pro-active stimulus suppression, alpha exhibited greater desynchronization at electrodes contralateral to the distractor, and SSVEP amplitudes either increased or showed no difference relative to a pre-stimulus baseline. These findings, together with other recent findings, question the role of alpha as a neural mechanism for active (top-down) stimulus suppression. In the future we intend to further elaborate on these unexpected results regarding distractor processing in visual search and will expand the scope of our studies to include feature-based selective attention as well as spatial-based attentional designs. In particular, the functional role of alpha modulations in feature-based attention will be investigated in paradigms that manipulate attentional load and facilitate color processing globally throughout the visual fields. We are convinced that our results will contribute significantly to the understanding of the neural systems that underlie visual selective attention and might call into question some of the established models of the role of alpha oscillations in attention.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partner: Professor Dr. Steven A. Hillyard