Cerebellar tDCS Modulates Neural Circuits during Semantic Prediction: A Combined tDCS-fMRI Study

Area of Science:

• Neuroscience
• Cognitive Science
• Psycholinguistics

Background:

• The cerebellum's role in language processing is increasingly recognized, extending beyond motor control.
• Internal models acquired by the cerebellum may facilitate predictive functions in cognition.
• Semantic prediction in language aids speech production and comprehension.

Purpose of the Study:

• To investigate the cerebellum's specific contribution to semantic prediction in language.
• To examine the neural and behavioral effects of modulating the right posterolateral cerebellum during predictive language tasks.

Main Methods:

• Combined functional magnetic resonance imaging (fMRI) and transcranial direct current stimulation (tDCS).
• Healthy adults (n=32) completed a sentence completion task with varying predictability.
• Anodal or sham tDCS was applied to the right posterolateral cerebellum before fMRI acquisition.

Main Results:

• Completion of predictive sentences increased activation in the right cerebellar Crus I/II.
• Anodal tDCS, compared to sham, enhanced activation in right Crus I/II during semantic prediction.
• Cerebellar tDCS improved resting-state functional connectivity within language networks.

Conclusions:

• The right posterolateral cerebellum is specifically involved in semantic prediction during sentence processing.
• Cerebellar internal models of linguistic stimuli support predictive language functions.
• Neuromodulation of the cerebellum impacts neural activation and connectivity within language networks.