Theta oscillations support the interface between language and memory

Yi Pu; Douglas Cheyne; Yanan Sun; Blake W Johnson

doi:10.1016/j.neuroimage.2020.116782

Theta oscillations support the interface between language and memory

Neuroimage. 2020 Jul 15:215:116782. doi: 10.1016/j.neuroimage.2020.116782. Epub 2020 Apr 8.

Authors

Yi Pu¹, Douglas Cheyne², Yanan Sun³, Blake W Johnson⁴

Affiliations

¹ Department of Neuroscience, Max-Planck-Institute for Empirical Aesthetics, Frankfurt am Main, Hesse 60322, Germany; ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, NSW 2109, Australia; Department of Cognitive Science, Macquarie University, Sydney, NSW 2109, Australia. Electronic address: yi.pu@ae.mpg.de.
² Program in Neurosciences and Mental Health, Hospital for Sick Children Research Institute, Toronto, Ontario, M5G 0A4, Canada; Department of Medical Imaging, University of Toronto, Toronto, Ontario, M5T 1W7, Canada.
³ ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, NSW 2109, Australia; Department of Psychology, Macquarie University, Sydney, NSW 2109, Australia.
⁴ ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, NSW 2109, Australia; Department of Cognitive Science, Macquarie University, Sydney, NSW 2109, Australia. Electronic address: blake.johnson@mq.edu.au.

PMID: 32276054
DOI: 10.1016/j.neuroimage.2020.116782

Abstract

Recent evidence shows that hippocampal theta oscillations, usually linked to memory and navigation, are also observed during online language processing, suggesting a shared neurophysiological mechanism between language and memory. However, it remains to be established what specific roles hippocampal theta oscillations may play in language, and whether and how theta mediates the communication between the hippocampus and the perisylvian cortical areas, generally thought to support language processing. With whole-head magnetoencephalographic (MEG) recordings, the present study investigated these questions with two experiments. Using a violation paradigm, extensively used for studying neural underpinnings of different aspects of linguistic processing, we found increased theta power (4-8 Hz) in the hippocampal formation, when participants read a semantically incorrect vs. correct sentence ending. Such a pattern of results was replicated using different sentence stimuli in another cohort of participants. Importantly, no significant hippocampal theta power increase was found when participants read a semantically correct but syntactically incorrect sentence ending vs. a correct sentence ending. These findings may suggest that hippocampal theta oscillations are specifically linked to lexical-semantic related processing, and not general information processing in sentence reading. Furthermore, we found significantly transient theta phase coupling between the hippocampus and the left superior temporal gyrus, a hub area of the cortical network for language comprehension. This transient theta phase coupling may provide an important channel that links the memory and language systems for the generation of sentence meaning. Overall, these findings help specify the role of hippocampal theta in language, and provide a novel neurophysiological mechanism at the network level that may support the interface between memory and language.

Keywords: Hippocampus; Magnetoencephalography (MEG); Online sentence reading; Theta oscillations.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adolescent
Adult
Brain Mapping
Female
Hippocampus / physiology*
Humans
Language*
Magnetoencephalography
Male
Memory / physiology*
Reading
Semantics
Theta Rhythm*
Young Adult