Perceptually relevant speech tracking in auditory and motor cortex reflects distinct linguistic features

• DOI: 10.1371/journal.pbio.2004473
• Publication Date: 2018-03-12T17:24:08Z
• Authors: Anne Keitel; Joachim Gross; Christoph Kayser
• Keywords: Neurocomputational speech processing

During online speech processing, our brain tracks the acoustic fluctuations in at different timescales. Previous research has focused on generic timescales (for example, delta or theta bands) that are assumed to map onto linguistic features such as prosody syllables. However, given high intersubject variability speaking patterns, a association between of activity and properties can be ambiguous. Here, we analyse tracking source-localised magnetoencephalographic data by directly focusing extracted from statistical regularities material. This revealed widespread significant phrases (0.6-1.3 Hz), words (1.8-3 syllables (2.8-4.8 phonemes (8-12.4 Hz). Importantly, when examining its perceptual relevance, found stronger for correctly comprehended trials left premotor (PM) cortex phrasal scale well middle temporal word scale. Control analyses using bands confirmed these effects were specific stimuli. Furthermore, phase timescale coupled power beta frequency (13-30 Hz) motor areas. cross-frequency coupling presumably reflects top-down prediction ongoing perception. Together, results reveal functional perceptually relevant roles distinct processes along auditory-motor pathway.