Spectrotemporal cortical dynamics and semantic control during sentence completion.

• Sentence completion is associated with three distinct patterns of cortical oscillations in magnetoencephalography (MEG). • The semantic control network displays differential interhemispheric dynamics in its temporal component during this task. • Demonstrates the potential of MEG in preoperative language mapping and understanding language alterations in neurological disorders. To investigate cortical oscillations during a sentence completion task (SC) using magnetoencephalography (MEG), focusing on the semantic control network (SCN), its leftward asymmetry, and the effects of semantic control load. Twenty right-handed adults underwent MEG while performing SC, consisting of low cloze (LC: multiple responses) and high cloze (HC: single response) stimuli. Spectrotemporal power modulations as event-related synchronizations (ERS) and desynchronizations (ERD) were analyzed: first, at the whole-brain level; second, in key SCN regions, posterior middle/inferior temporal gyri (pMTG/ITG) and inferior frontal gyri (IFG), under different semantic control loads. Three cortical response patterns emerged: early (0–200 ms) theta-band occipital ERS; intermediate (200–700 ms) semantic network alpha/beta-band ERD; late (700–3000 ms) dorsal language stream alpha/beta/gamma-band ERD. Under high semantic control load (LC), pMTG/ITG showed prolonged left-sided engagement (ERD) and right-sided inhibition (ERS). Left IFG exhibited heightened late (2500–2550 ms) beta-band ERD with increased semantic control load (LC vs. HC). SC involves distinct cortical responses and depends on the left IFG and asymmetric engagement of the pMTG/ITG for semantic control. Future use of SC in neuromagnetic preoperative language mapping and for understanding the pathophysiology of language disorders in neurological conditions. [ABSTRACT FROM AUTHOR]