PT  - JOURNAL ARTICLE
AU  - Nai Ding
AU  - Xunyi Pan
AU  - Cheng Luo
AU  - Naifei Su
AU  - Wen Zhang
AU  - Jianfeng Zhang
TI  - Attention is required for knowledge-based sequential grouping of syllables into words
AID  - 10.1101/135053
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 135053
4099  - http://biorxiv.org/content/early/2017/05/08/135053.short
4100  - http://biorxiv.org/content/early/2017/05/08/135053.full
AB  - 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 critically relies on the listener’s lexical knowledge. This study investigates whether top-down attention is required to apply lexical knowledge to group syllables into words, by concurrently monitoring neural entrainment to syllables and words using electroencephalography (EEG). When attention is directed to a competing speech stream or cross-modally to a silent movie, neural entrainment to syllables is weakened but neural entrainment to words largely diminishes. 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.