Abstract: The mapping problem, which seeks to establish correspondences between linguistic phenomena and their underlying neural mechanisms, has emerged as a significant research focus. Syntactic parsing, defined as the process by which linear speech sequences are incrementally converted into abstract hierarchical syntactic structures, is considered a fundamental aspect of human language processing. Understanding the neural basis of syntactic parsing is crucial for advancing research on the mapping problem in language and neuroscience. Recent studies have increasingly demonstrated the feasibility of using low-frequency neural oscillation as index for constructing syntactic hierarchies, positioning these oscillations as strong candidates for explaining the neural mechanisms involved in syntactic processing. By dissociating syntactic knowledge from prosodic information, semantic statistical information, and lexical properties, these studies have found a significant correlation between low-frequency neural oscillatory activity and the processes involved in constructing linguistic hierarchies, which indicated that the prior grammatical knowledge is the prerequisite for robust linguistic hierarchy construction, further providing evidence supporting the psychological reality of syntactic processing.
Furthermore, increasing attention has been directed toward the potential relationship between phase coherence in neural oscillations and different levels of linguistic structure. Research suggests that neural clusters may represent syntactic hierarchies through phase synchronization or desynchronization within the same frequency band or across different frequency bands. As the processing of linguistic input unfolds over time, different neural clusters are progressively activated or inhibited, generating oscillatory signals with distinct phase properties. These oscillatory dynamics contribute to the storage, maintenance, and retrieval of sensory information across different temporal scales, thereby facilitating the dynamic encoding of hierarchical linguistic structures. This capacity for dynamic encoding through temporally coordinated neural oscillations is thought to be critical for constructing linguistic hierarchies, as it enables the brain to process complex syntactic information in real time.
Several theoretical models, including ROSE, CNAL, SMMM, DORA, VS-BIND have been proposed to explain how neural oscillations relate to syntactic parsing. Within the framework of David Marr’s theory, these models have given a comprehensive description of syntactic parsing and its neural mechanism from the perspective of implementational level, algorithmic level, and computational level, which indicates the non-isomorphic relationship between the temporal structure of neural oscillations and the construction of syntactic hierarchies. The temporal distribution of phase properties in neural oscillations provides a plausible framework for understanding how neural activity encodes syntactic parsing processes. These insights offer a potential solution to the mapping problem by elucidating how different neural oscillatory dynamics might underlie the incremental construction of syntactic structures. This line of research, therefore, holds considerable promise for advancing our understanding of the neural basis of language processing.
Future research on the relationship between neural oscillations and syntactic parsing can focus on several promising directions. First, achieving finer-grained alignment and causal inference between neural oscillatory activity and the specific stages of syntactic processing will be essential for clarifying how neural signals correspond to different aspects of syntactic hierarchy construction. Second, investigating the mechanisms underlying the generation of neural oscillations and exploring their broader biological significance could provide important insights into how oscillatory activity supports language processing. Third, understanding how neural oscillations change during the course of language development in children will be critical for uncovering the developmental trajectories of neural circuits involved in syntactic parsing. Lastly, examining the neurophysiological foundations of language disorders and identifying how disruptions in neural oscillatory patterns contribute to these conditions could inform new approaches to diagnosis and rehabilitation.

Key words: neural oscillation, language comprehension, syntactic parsing, the minimalist program, incremental conversion