目的:使用脑磁图(MEG)研究句子完成任务(SC)期间的皮质振荡,专注于语义控制网络(SCN),它向左的不对称性,以及语义控件负载的影响。
方法:二十名惯用右手的成年人在进行SC时接受了MEG,由低完形填空(LC:多重反应)和高完形填空(HC:单一反应)刺激组成。分析了与事件相关的同步(ERS)和去同步(ERD)的光谱时间功率调制:首先,在全脑水平;第二,在关键SCN区域中,后中/颞下回(pMTG/ITG)和下额回(IFG),在不同的语义控制负载下。
结果:出现了三种皮层反应模式:早期(0-200ms)θ带枕骨ERS;中间(200-700ms)语义网络α/β带ERD;晚期(700-3000ms)背语言流α/β/γ带ERD。在高语义控制负荷(LC)下,pMTG/ITG显示延长的左侧参与(ERD)和右侧抑制(ERS)。左IFG表现出增强的晚期(2500-2550ms)β波段ERD,语义控制负荷增加(LC与HC)。
结论:SC涉及不同的皮层反应,并依赖于左侧IFG和pMTG/ITG的不对称参与进行语义控制。
结论:未来将SC用于神经磁术前语言作图和了解神经系统疾病中语言障碍的病理生理学。
OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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).
CONCLUSIONS: SC involves distinct cortical responses and depends on the left IFG and asymmetric engagement of the pMTG/ITG for semantic control.
CONCLUSIONS: Future use of SC in neuromagnetic preoperative language mapping and for understanding the pathophysiology of language disorders in neurological conditions.