Entraining rhythms of the brain to study the neurodevelopment of perception and cognition is a fascinating idea. In principle, entrainment endows the experimenter with increased control over the timing of fundamental neural processes. Yet, its appeal has also created a flurry of neuroscientific research that may apply this idea prematurely. Can we simply infer entrainment
just because we are using rhythmic stimulation? It is underappreciated that there is no clear response to this question yet. This should make us more cautious not only in interpreting findings about the role of neural rhythms in perception and cognition, but also in testing rhythmic sensory stimulation as a clinical intervention for psychopathologies.
Köster et al. (2019) studied the neurodevelopment of action expectations by presenting infants with rhythmically flickering stimuli while recording their EEGs. The authors assumed that this rhythmic stimulation entrained endogenous brain oscillations. In turn, they interpreted a band-limited difference between conditions as a modulation of infant theta oscillations. In our commentary, we discuss this assumption critically. We show how a similar pattern of results can arise from a simulated hypothetical scenario. We did not intend to simulate EEG data in their full complexity, but instead present a simplified model that makes a minimal number of assumptions. Crucially, this model does not require the involvement of entrained endogenous brain oscillations. Our findings may serve as a word of caution on inferring entrainment from (conditional effects on) band-limited neural responses in the context of rhythmic sensory stimulation, and interpreting these findings in the context of endogenous neural oscillations, in neurodevelopment and beyond.
Obleser J, Henry MJ, Lakatos P. What do we talk about when we talk about rhythm?. PLoS biology. 2017 Sep 19;15(9):e2002794.
Keitel C, Quigley C, Ruhnau P. Stimulus-driven brain oscillations in the alpha range: entrainment of intrinsic rhythms or frequency-following response?. Journal of Neuroscience. 2014 Jul 30;34(31):10137-40.
* Blogpost based on unpublished article elements produced as part of the submission process. As such, these have been edited by the co-authors Molly Henry, Sarah Jessen, and Jonas Obleser and have been part of the journal review process.