Cortical Oscillatory Hierarchy for Natural Sentence Processing

Bin Zhao, Jianwu Dang, Gaoyan Zhang, Masashi Unoki

Human speech processing, either for listening or oral reading, requires dynamic cortical activities that are not only driven by sensory stimuli externally but also influenced by semantic knowledge and speech planning goals internally. Each of these functions has been known to accompany specific rhythmic oscillations and be localized in distributed networks. The question is how the brain organizes these spatially and spectrally distinct functional networks in such a temporal precision that endows us with incredible speech abilities. For clarification, this study conducted an oral reading task with natural sentences and collected simultaneously the involved brain waves, eye movements, and speech signals with high-density EEG and eye movement equipment. By examining the regional oscillatory spectral perturbation and modeling the frequency-specific interregional connections, our results revealed a hierarchical oscillatory mechanism, in which gamma oscillation entrains with the fine-structured sensory input while beta oscillation modulated the sensory output. Alpha oscillation mediated between sensory perception and cognitive function via selective suppression. Theta oscillation synchronized local networks for large-scale coordination. Differing from a single function-frequency-correspondence, the coexistence of multi-frequency oscillations was found to be critical for local regions to communicate remotely and diversely in a larger network.

 DOI: 10.21437/Interspeech.2020-1633

Cite as: Zhao, B., Dang, J., Zhang, G., Unoki, M. (2020) Cortical Oscillatory Hierarchy for Natural Sentence Processing. Proc. Interspeech 2020, 125-129, DOI: 10.21437/Interspeech.2020-1633.

  author={Bin Zhao and Jianwu Dang and Gaoyan Zhang and Masashi Unoki},
  title={{Cortical Oscillatory Hierarchy for Natural Sentence Processing}},
  booktitle={Proc. Interspeech 2020},