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

Abstract

It has been proposed that the cerebellum acquires internal models of mental processes that enable prediction, allowing for the optimization of behavior. In language, semantic prediction speeds speech production and comprehension. Right cerebellar lobules VI and VII (including Crus I/II) are engaged during a variety of language processes and are functionally connected with cerebral cortical language networks. Further, right posterolateral cerebellar neuromodulation modifies behavior during predictive language processing. These data are consistent with a role for the cerebellum in semantic processing and semantic prediction. We combined transcranial direct current stimulation (tDCS) and fMRI to assess the behavioral and neural consequences of cerebellar tDCS during a sentence completion task. Task-based and resting-state fMRI data were acquired in healthy human adults (n ϭ 32; ϭ 23.1 years) both before and after 20 min of 1.5 mA anodal (n ϭ 18) or sham (n ϭ 14) tDCS applied to the right posterolateral cerebellum. In the sentence completion task, the first four words of the sentence modulated the predictability of the final target word. In some sentences, the preceding context strongly predicted the target word, whereas other sentences were nonpredictive. Completion of predictive sentences increased activation in right Crus I/II of the cerebellum. Relative to sham tDCS, anodal tDCS increased activation in right Crus I/II during semantic prediction and enhanced resting-state functional connectivity between hubs of the reading/language networks. These results are consistent with a role for the right posterolateral cerebellum beyond motor aspects of language, and suggest that cerebellar internal models of linguistic stimuli support semantic prediction.

Cerebellar Contributions to Language in Typical and Atypical Development: A Review

“…In addition, D’Mello and colleagues (2017) recently reported in a combined tDCS and fMRI study that, relative to sham, anodal tDCS of the right posterolateral cerebellum increased activation in right Crus I/II during a semantic prediction task. These studies provide initial suggestion that predictive encoding in the cerebellum contributes to the speed and efficiency of language processing (D’Mello et al, 2017). …”

Reorganization of cerebro‐cerebellar circuit in patients with left hemispheric gliomas involving language network: A combined structural and resting‐state functional MRI study

“…However, in order to make the conclusion more strict and convincible, the new 2016 WHO classification system should be adopted in the future studies. As mentioned above, therapeutic interventions, such as TMS or tDCS on cerebellum have been applied to improve language/cognitive function or induce brain network reorganization (D'Mello et al, 2017;Gallea et al, 2016;Grimaldi et al, 2016;Halko et al, 2014;Pope & Miall, 2012). The BOLD signal tightly adjacent to tumor was thus naturally ignored at the individual level during this process.…”

“…Sixth, we did not perform therapeutic intervention to testify the clinical significance of the observed functional and structural alterations in cerebellum and cerebro-cerebellar circuit. As mentioned above, therapeutic interventions, such as TMS or tDCS on cerebellum have been applied to improve language/cognitive function or induce brain network reorganization (D'Mello et al, 2017;Gallea et al, 2016;Grimaldi et al, 2016;Halko et al, 2014;Pope & Miall, 2012). How to precisely interfere with these targets, in an evoking or inhibitive manner, is necessary to be elucidated in the future to achieve the translational significance.…”

Functional connectivity strength within the auditory forebrain is altered by song learning and predicts song stereotypy in developing male zebra finches

“…Although the cerebellum has a widely recognized, if incompletely understood, role in fine motor control (for review, see Manto et al, 2012), its potential contribution to song learning and/or production has received relatively little attention. In contrast, a large and growing body of evidence suggests that the cerebellum plays important roles in various aspects of human language (for reviews, see Hertrich, Mathiak, & Ackermann, 2016;Pleger & Timmann, 2018;Ziegler & Ackermann, 2017), including linguistic prediction (D'Mello, Turkeltaub, & Stoodley, 2017;Lesage, Hansen, & Miall, 2017;Lesage, Morgan, Olson, Meyer, & Miall, 2012;Moberget, Gullesen, Andersson, Ivry, & Endestad, 2014), verbal working memory Kirschen, Chen, Schraedley-Desmond, & Desmond, 2005;Ravizza et al, 2006), and word generation (Arasanz, Staines, Roy, & Schweizer, 2012). Recently, a link was found between the songbird anterior forebrain pathway (AFP) and the cerebellum (Perkel, 2004).…”