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Understanding the correct intention of a speaker is critical for social interaction. Speech prosody is an important source for understanding speakers' intentions during verbal communication. However, the neural dynamics by which the human brain translates the prosodic cues into a mental representation of communicative intentions in real time remains unclear. Here, we recorded EEG (electroencephalograph) while participants listened to dialogues. The prosodic features of the critical words at the end of sentences were manipulated to signal either suggestion, warning, or neutral intentions. The results showed that suggestion and warning intentions evoked enhanced late positive event-related potentials (ERPs) compared to the neutral condition. Linear mixed-effects model (LMEM) regression and representational similarity analysis (RSA) analyses revealed that these ERP effects were distinctively correlated with prosodic acoustic analysis, emotional valence evaluation, and intention interpretation in different time windows; The onset latency significantly increased as the processing level of abstractness and communicative intentionality increased. Neural representations of intention and emotional information emerged and parallelly persisted over a long time window, guiding the correct identification of communicative intention. These results provide new insights into understanding the structural components of intention processing and their temporal neural dynamics underlying communicative intention comprehension from speech prosody in online social interactions.

• Intention comprehension from prosody involves multiple levels of neural representations. • Intentional level of representation is likely to emerge later than acoustic and emotion levels. • Emotional evaluation persists until late to guide the interpretation of intentions. Understanding the correct intention of a speaker is critical for social interaction. Speech prosody is an important source for understanding speakers' intentions during verbal communication. However, the neural dynamics by which the human brain translates the prosodic cues into a mental representation of communicative intentions in real time remains unclear. Here, we recorded EEG (electroencephalograph) while participants listened to dialogues. The prosodic features of the critical words at the end of sentences were manipulated to signal either suggestion, warning , or neutral intentions. The results showed that suggestion and warning intentions evoked enhanced late positive event-related potentials (ERPs) compared to the neutral condition. Linear mixed-effects model (LMEM) regression and representational similarity analysis (RSA) analyses revealed that these ERP effects were distinctively correlated with prosodic acoustic analysis, emotional valence evaluation, and intention interpretation in different time windows; The onset latency significantly increased as the processing level of abstractness and communicative intentionality increased. Neural representations of intention and emotional information emerged and parallelly persisted over a long time window, guiding the correct identification of communicative intention. These results provide new insights into understanding the structural components of intention processing and their temporal neural dynamics underlying communicative intention comprehension from speech prosody in online social interactions. [ABSTRACT FROM AUTHOR]

An Intention Processing Network (IPN), involving the medial prefrontal cortex, precuneus, bilateral posterior superior temporal sulcus, and temporoparietal junctions, plays a fundamental role in comprehending intentions underlying action goals. In a previous fMRI study, we showed that, depending on the linguistic or extralinguistic (gestural) modality used to convey the intention, the IPN is complemented by activation of additional brain areas, reflecting distinct modality-specific input gateways to the IPN. These areas involve, for the linguistic modality, the left inferior frontal gyrus (LIFG), and for the extralinguistic modality, the right inferior frontal gyrus (RIFG). Here, we tested the modality-specific gateway hypothesis, by using DCM to measure inter-regional functional integration dynamics between the IPN and LIFG/RIFG gateways. We found strong evidence of a well-defined effective connectivity architecture mediating the functional integration between the IPN and the inferior frontal cortices. The connectivity dynamics indicate a modality-specific propagation of stimulus information from LIFG to IPN for the linguistic modality, and from RIFG to IPN for the extralinguistic modality. Thus, we suggest a functional model in which the modality-specific gateways mediate the structural and semantic decoding of the stimuli, and allow for the modality-specific communicative information to be integrated in Theory of Mind inferences elaborated through the IPN. [ABSTRACT FROM AUTHOR]