Abstract:

This article provides a comprehensive evaluation of the neurocognitive mechanisms underlying vocal imitation, approached from the speaker's perspective through a multi-stage model. Initially, we dissect this process by analyzing stages in two different models of vocal imitation, illuminating the unique aspects of this cognitive function. Subsequent sections revisit neuroimaging studies to demystify the neural networks underpinning vocal imitation, clarifying specific neural mechanisms which drive cognitive processing in this domain. The third part of the discussion hones in on individual capabilities like voice recognition ability, the skill to map vocal perception onto vocal organ motor commands, and the control over vocal organs. These elements are crucial for comprehending how various factors contribute to the process of vocal imitation.

Firstly, we have clearly addressed the task irrelevant nature of vocal imitation. in a shadowing paradigm, neither the shadowing condition nor the tasks in stimulus-response consistency paradigms require speakers to imitate the voice of the target speaker. These paradigms provide measures of the cognitive processing of imitation through behavioral response indicators, suggesting that vocal imitation can work spontaneously. Under the imitation condition of the shadowing paradigm, speakers are asked to mimic the voice of the target speaker, revealing that vocal imitation can also be deliberately targeted at specific sounds. The spontaneity involved in vocal imitation differs between these paradigms: in stimulus-response consistency, it primarily manifests as automated reactions based on sensorimotor coupling, almost an automatic response triggered by stimuli. In contrast, the spontaneity in the shadowing paradigm is more about reproducing acoustic characteristics without explicit intent, meaning that speakers can accurately replicate the acoustic features of the target speaker even without a clear intention to imitate.

Secondly, we have deepened our understanding of the neural pathways integral to the perception and vocal motor activities that support vocal imitation. This exploration encompasses key neural structures such as the superior temporal gyrus, arcuate fasciculus, inferior frontal gyrus, laryngeal motor cortex, and basal ganglia, all of which are crucial in the selection, coordination, and execution of motor sequences.

Thirdly, the study further emphasizes the critical role of multimodal information in vocal imitation. It highlights how metrics, including the reproduction of acoustic features and the replication of vocal organ movements, are essential in delineating the intricate cognitive processes at play. This comprehensive examination not only sheds light on the complex neural mechanics underlying vocal imitation but also underscores the synergy between various sensory inputs and motor outputs in this sophisticated cognitive function.

In conclusion, this article unravels the cognitive neural foundations of vocal imitation, discussing its definition, behavioral evidence, neural mechanisms, and the role of individual differences. It is proposed that successful vocal imitation relies on the replication of acoustic features and the corresponding movements of the vocal organs. Critically, three primary stages are involved in vocal imitation—perception, perceptual mapping to output, and actual vocal output—significantly impact the behavioral outcomes of this process. An in-depth analysis of these stages enhances our understanding of the complexities of vocal imitation and illustrates the collaboration of various cognitive models and neural foundations in this phenomenon. Future research should integrate vocal imitation studies with vocal disorders and intracranial electrode technology, aiming to decipher the causal links between brain functions and behaviors, and apply these insights to lifelong speech development, cognitive plasticity, and predictive processing in language communication.

Key words: vocal imitation, vocal reenactment, vocal motor movements copy, imitation neural network, individual differences