Low-frequency neural activity reflects rule-based chunking during speech listening

• Published in: eLife Vol. 9
• Main Authors: Jin, Peiqing, Lu, Yuhan, Ding, Nai
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 20-04-2020; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Adult; Auditory Perception - physiology; Brain; chunking; Female; Grammar; Humans; Language; Learning - physiology; Linguistics; magnetoencephalographic; Magnetoencephalography; Male; Memory - physiology; Neuroscience; Personal digital assistants; Scientists; Semantic relations; Semantics; Speech; Speech - physiology; Speech Perception - physiology; speech sequence; Time; Young Adult; speech sequence; magnetoencephalographic; human; chunking; neuroscience
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.55613

Chunking is a key mechanism for sequence processing. Studies on speech sequences have suggested low-frequency cortical activity tracks spoken phrases, that is, chunks of words defined by tacit linguistic knowledge. Here, we investigate whether low-frequency cortical activity reflects a general mechanism for sequence chunking and can track chunks defined by temporarily learned artificial rules. The experiment records magnetoencephalographic (MEG) responses to a sequence of spoken words. To dissociate word properties from the chunk structures, two tasks separately require listeners to group pairs of semantically similar or semantically dissimilar words into chunks. In the MEG spectrum, a clear response is observed at the chunk rate. More importantly, the chunk-rate response is task-dependent. It is phase locked to chunk boundaries, instead of the semantic relatedness between words. The results strongly suggest that cortical activity can track chunks constructed based on task-related rules and potentially reflects a general mechanism for chunk-level representations.