Attention modulation of neural entrainment to hierarchical linguistic structures
【摘要】：How the brain sequentially groups sensory events into temporal chunks and how this process is modulated by attention are fundamental questions in cognitive neuroscience. Sequential grouping includes bottom-up primitive grouping and top-down knowledge-based grouping. In speech perception, grouping acoustic features into syllables can rely on bottom-up acoustic continuity cues but grouping syllables into words and phrases critically relies on the listener's lexical and syntactic knowledge. This study investigates whether top-down attention is required to apply lexical and syntactic knowledge to group syllables into words and phrases, by concurrently monitoring neural entrainment to syllables, words, and phrases using electroencephalography(EEG). By manipulating the stimulus linguistic structure and the task, we demonstrate that neural entrainment to higher-level linguistic units is much more sensitive to top-down attention compared with neural entrainment to lower-level linguistic units. These results strongly suggest that knowledge-based grouping of syllables into words requires top-down attention and is a bottleneck for the neural processing of unattended speech.