Functional brain plasticity during L1 training on complex sentences: Changes in gamma-band oscillatory activity

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• The adult brain exhibits plasticity, but its capacity to modify the language network through first language (L1) training is not well understood.
• Investigating neural changes associated with L1 training is crucial for understanding adult brain plasticity and language processing.

Purpose of the Study:

• To investigate whether longitudinal training in syntactically complex German sentence comprehension can alter the language network in adult native speakers.
• To examine the neural mechanisms underlying improvements in L1 comprehension after training.

Main Methods:

• A 4-day longitudinal training experiment involving 30 adult native German speakers.
• Magnetoencephalography (MEG) was used to record brain activity during comprehension of syntactically complex sentences (varying in relative clause depth).
• Spectral power analysis and functional connectivity analysis were performed on MEG data, correlated with behavioral performance.

Main Results:

• Training led to decreased gamma power in Brodmann area 44 (BA 44) for complex sentences, indicating neural adaptation.
• Increased gamma-band functional connectivity between BA 44 and other language-related regions (inferior frontal sulcus, inferior parietal cortex) correlated with improved comprehension.
• Behavioral improvements in complex L1 sentence comprehension were observed after training.

Conclusions:

• Complex L1 sentence training can enhance language performance and modify neural activity in the adult brain's language network.
• Training strengthens the dorsal processing stream and working-memory regions for syntactically demanding L1 sentences.
• These findings demonstrate significant functional plasticity in the adult brain for L1 processing.