How the Listener's Attention Dynamically Switches Between Different Speakers During a Natural Conversation.

The neural mechanisms underpinning the dynamic switching of a listener's attention between speakers are not well understood. Here we addressed this issue in a natural conversation involving 21 triadic adult groups. Results showed that when the listener's attention dynamically switched between speakers, neural synchronization with the to-be-attended speaker was significantly enhanced, whereas that with the to-be-ignored speaker was significantly suppressed.

Neural tracking of speech envelope does not unequivocally reflect intelligibility.

During listening, brain activity tracks the rhythmic structures of speech signals. Here, we directly dissociated the contribution of neural envelope tracking in the processing of speech acoustic cues from that related to linguistic processing. We examined the neural changes associated with the comprehension of Noise-Vocoded (NV) speech using magnetoencephalography (MEG).

Distracting linguistic information impairs neural tracking of attended speech.

Listening to speech is difficult in noisy environments, and is even harder when the interfering noise consists of intelligible speech as compared to unintelligible sounds. This suggests that the competing linguistic information interferes with the neural processing of target speech. Interference could either arise from a degradation of the neural representation of the target speech, or from increased representation of distracting speech that enters in competition with the target speech.

The Relation between Alpha/Beta Oscillations and the Encoding of Sentence induced Contextual Information.

Pre-stimulus alpha (8-12 Hz) and beta (16-20 Hz) oscillations have been frequently linked to the prediction of upcoming sensory input. Do these frequency bands serve as a neural marker of linguistic prediction as well? We hypothesized that if pre-stimulus alpha and beta oscillations index language predictions, their power should monotonically relate to the degree of predictability of incoming words based on past context. We expected that the more predictable the last word of a sentence, the stronger the alpha and beta power modulation.

Neural mechanisms for selectively tuning in to the target speaker in a naturalistic noisy situation.

The neural mechanism for selectively tuning in to a target speaker while tuning out the others in a multi-speaker situation (i.e., the cocktail-party effect) remains elusive.

Pure linguistic interference during comprehension of competing speech signals.

Speech-in-speech perception can be challenging because the processing of competing acoustic and linguistic information leads to informational masking. Here, a method is proposed to isolate the linguistic component of informational masking while keeping the distractor's acoustic information unchanged. Participants performed a dichotic listening cocktail-party task before and after training on 4-band noise-vocoded sentences that became intelligible through the training.

Leader emergence through interpersonal neural synchronization.

The neural mechanism of leader emergence is not well understood. This study investigated (i) whether interpersonal neural synchronization (INS) plays an important role in leader emergence, and (ii) whether INS and leader emergence are associated with the frequency or the quality of communications. Eleven three-member groups were asked to perform a leaderless group discussion (LGD) task, and their brain activities were recorded via functional near infrared spectroscopy (fNIRS)-based hyperscanning.

White and grey matter changes in the language network during healthy aging.

Neural structures change with age but there is no consensus on the exact processes involved. This study tested the hypothesis that white and grey matter in the language network changes during aging according to a "last in, first out" process. The fractional anisotropy (FA) of white matter and cortical thickness of grey matter were measured in 36 participants whose ages ranged from 55 to 79 years.

Neural synchronization during face-to-face communication.

Although the human brain may have evolutionarily adapted to face-to-face communication, other modes of communication, e.g., telephone and e-mail, increasingly dominate our modern daily life.