The multiple phonological activation in Chinese spoken word production: An ERP study in a word translation task

The neural mechanisms underlying the processing of consonant, vowel and tone during Chinese typing: an fNIRS study

Many studies have explored the role of consonant, vowel, and tone in Chinese word identification or sentence comprehension. However, few studies have explored their roles and neural basis during Chinese word production, especially when involving neural basis. The present fNIRS study investigated the neural mechanisms of consonant, vowel, and tone processing during Chinese typing. Participants were asked to name the Chinese characters displayed on a computer screen by typing on a keyboard while hearing a simultaneously presented auditory stimulus. The auditory stimulus was either consistent with the characters' pronunciation (consistent condition) or mismatched in the consonant, vowel, or tone of the character pronunciation. The fNIRS results showed that compared with the consistent condition (as baseline), the consonant mismatch condition evoked lower levels of oxygenated hemoglobin (HbO) activation in the left inferior frontal gyrus Broca's triangle and left superior temporal gyrus. Vowel mismatch condition evoked a higher level of HbO activation in the top of the left inferior frontal gyrus and left middle frontal gyrus. The regions and patterns of brain activation evoked by tone mismatch were the same as those of vowel mismatch. The study indicated that consonant, vowel and tone all play a role in Chinese character production. The sensitive brain areas were all in the left hemisphere. However, the neural mechanism of consonant processing differed from vowel processing in both brain regions and patterns, while tone and vowel processing shared the same regions.

The multiple phonological activation in Chinese spoken word production: An ERP study supporting cascaded model

A central issue in spoken word production concerns how activation is transmitted from semantic to phonological levels. The current study investigated the issue of seriality and cascadedness in Chinese spoken word production, via the combined semantic blocked paradigm (with homogeneous and heterogeneous blocks) and picture-word interference paradigm (with phonologically related, mediated and unrelated distractors). Naming latencies data showed a mediated effect via comparing mediated and unrelated distractors in homogeneous blocks, a phonological facilitation effect via comparing phonologically related and unrelated distractors in homogeneous and heterogeneous blocks, and a semantic interference effect via comparing homogeneous and heterogeneous blocks. Critically, cluster-based permutation test of ERP data demonstrated a mediated effect around 266-326ms and an overlapped pattern of semantic interference effect around 264-418ms and phonological facilitation effect around 210-310ms in homogeneous or around 236-316ms in heterogeneous blocks. These findings indicated that speakers activate phonological nodes of non-targets, and present a cascadedness pattern of the transmission from semantics to phonology in Chinese spoken production. The present study sheds new insight on the neural correlates of semantic and phonological effects, and provides behavioral and electrophysiological evidences for the cascaded model within a theoretical framework of lexical competition in speech production.

Semantically congruent audiovisual integration with modal-based attention accelerates auditory short-term memory retrieval

Evidence has shown that multisensory integration benefits to unisensory perception performance are asymmetric and that auditory perception performance can receive more multisensory benefits, especially when the attention focus is directed toward a task-irrelevant visual stimulus. At present, whether the benefits of semantically (in)congruent multisensory integration with modal-based attention for subsequent unisensory short-term memory (STM) retrieval are also asymmetric remains unclear. Using a delayed matching-to-sample paradigm, the present study investigated this issue by manipulating the attention focus during multisensory memory encoding. The results revealed that both visual and auditory STM retrieval reaction times were faster under semantically congruent multisensory conditions than under unisensory memory encoding conditions. We suggest that coherent multisensory representation formation might be optimized by restricted multisensory encoding and can be rapidly triggered by subsequent unisensory memory retrieval demands. Crucially, auditory STM retrieval is exclusively accelerated by semantically congruent multisensory memory encoding, indicating that the less effective sensory modality of memory retrieval relies more on the coherent prior formation of a multisensory representation optimized by modal-based attention.