Lecture by Christian Keitel: Visual perception and alpha rhythms
in the brain - new twists in an ongoing story

Nearly a century ago Hans Berger first described the human alpha rhythm. Since then we have covered considerable ground in learning about the role of this periodic brain activity in perception and cognition. Still, with the precision of our instruments constantly evolving, our picture of alpha and its functional role grows ever more complex. My talk will touch on two trendy aspects of alpha in visual processing. First, I will critically discuss whether the alpha rhythm can be externally driven or "entrained" through periodic visual stimulation and pit this notion against seemingly contradictory findings from frequency-tagging research (i.e. studying visual processing with flicker). Secondly, fluctuations in alpha influence the perception of subsequently presented stimuli. We tend to think of these pre-stimulus fluctuations as spontaneous, stochastic processes. Challenging this idea in a recent line of M/EEG, we found that at least part of this pre-stimulus variability in alpha can be accounted for by long term trends in alpha power and frequency (1-2 hrs) during continuous task performance. I will discuss implications of these findings for studying the relationship of pre-stimulus alpha and (measures of) behavioural performance.

Location: Think Tank, 4th floor