When does sensory entrainment exceed evoked responses?

Determine the empirical conditions and diagnostic signatures under which stimulus–brain coupling reflects synchronization of endogenous neural oscillators (sensory entrainment) rather than merely stimulus-evoked responses, across periodic and quasi-periodic sensory stimulation paradigms (e.g., auditory speech and music, visual rhythms).

Background

Sensory entrainment is widely hypothesized to occur when neural oscillators synchronize to rhythmic external input. However, periodic stimulation also elicits evoked responses, making it challenging to distinguish genuine entrainment from stimulus-driven activity in EEG/MEG. This ambiguity affects interpretations of findings in domains such as speech and music and has implications for applications like brain–computer interfaces and rhythmic therapeutic interventions.

Clarifying criteria that decisively indicate involvement of endogenous oscillators—beyond mere tracking of stimulus dynamics—would refine methodologies and theoretical models and resolve current interpretational debates.

References

In sum, sensory entrainment is an often-assumed mechanism for the processing of (quasi-) rhythmic input, but it is still unclear under which circumstances stimulus-brain coupling goes beyond evoked neural responses.

— Brain rhythms in cognition -- controversies and future directions  (2507.15639 - Keitel et al., 21 Jul 2025) in Section 1.1.c Sensory entrainment

In this regard, two considerations should be taken into account when interpreting the findings. First, beyond its utility for probing periodic attentional dynamics, this visual timing paradigm and the associated temporal filling-in effect reflect the characteristics of sustained visual attention in general (extended theoretical discussion in Huang et al., 2024). Second, while the recorded visual SSEP reflected the effect of dynamic visual attention, it was not a direct measure of the source attention state itself; how to isolate the rhythmic attentional control from its downstream effect remains an open question.

— Temporal filling-in reduces attentional fluctuations in sustained visual attention  (2608.22722 - Huang et al., 24 Aug 2026) in Discussion, paragraph beginning “Attentional states wax and wane moment to moment”