Syntax and the brain: disentangling grammar by selective anomalies

Area of Science:

• Neuroscience
• Linguistics
• Cognitive Science

Background:

• Traditional language studies often fail to distinguish between semantic, morphological, and syntactic processing in the brain.
• Existing functional imaging paradigms frequently use word lists or do not control for semantic influences, complicating the isolation of grammatical processing.
• Differentiating neural correlates for distinct linguistic components is essential for understanding brain function in language.

Purpose of the Study:

• To isolate the functional brain activity associated with morphological and syntactic processing.
• To investigate the neural basis of grammatical computation by controlling for semantic influences.
• To identify specific brain regions involved in processing sentence structure and word formation.

Main Methods:

• Employed Positron Emission Tomography (PET) to measure brain activity.
• Designed an experiment requiring participants to detect anomalies in written sentences composed of pseudowords to neutralize lexical-semantic access.
• Focused on analyzing brain responses during syntactic and morphosyntactic processing tasks.

Main Results:

• Identified involvement of a deep component of Broca's area and a right inferior frontal region in both syntactic and morphosyntactic processing.
• Observed activation in the left caudate nucleus and insula exclusively during syntactic processing, suggesting their role in syntactic computation.
• Demonstrated selective activation patterns corresponding to distinct levels of linguistic analysis.

Conclusions:

• Provided in vivo evidence for a neural network involved in morphological and syntactic computation.
• Highlighted the specific roles of Broca's area, right inferior frontal regions, left caudate nucleus, and insula in grammatical processing.
• Supported the existence of distinct neural substrates for different components of language processing within the brain.