Cerebellar rTMS disrupts predictive language processing

Abstract

SummaryThe human cerebellum plays an important role in language, amongst other cognitive and motor functions [1], but a unifying theoretical framework about cerebellar language function is lacking. In an established model of motor control, the cerebellum is seen as a predictive machine, making short-term estimations about the outcome of motor commands. This allows for flexible control, on-line correction, and coordination of movements [2]. The homogeneous cytoarchitecture of the cerebellar cortex suggests that similar computations occur throughout the structure, operating on different input signals and with different output targets [3]. Several authors have therefore argued that this ‘motor’ model may extend to cerebellar nonmotor functions [3–5], and that the cerebellum may support prediction in language processing [6]. However, this hypothesis has never been directly tested. Here, we used the ‘Visual World’ paradigm [7], where on-line processing of spoken sentence content can be assessed by recording the latencies of listeners' eye movements towards objects mentioned. Repetitive transcranial magnetic stimulation (rTMS) was used to disrupt function in the right cerebellum, a region implicated in language [8]. After cerebellar rTMS, listeners showed delayed eye fixations to target objects predicted by sentence content, while there was no effect on eye fixations in sentences without predictable content. The prediction deficit was absent in two control groups. Our findings support the hypothesis that computational operations performed by the cerebellum may support prediction during both motor control and language processing.

Multimodal connectivity of motor learning-related dorsal premotor cortex

“…In the right cerebellum, connectivity included regions associated with the lower hand representation in lobule HVIII (Thickbroom et al, 2003; Yeo et al, 2011), consistent with the importance of the cerebellum in motor control (Hardwick et al, 2014, 2013). Bilateral connectivity was also identified with lobules HVII (Crus I and II), which are involved in cognitive and linguistic processes (Lesage et al, 2012; Stoodley and Schmahmann, 2009), and are functionally connected to DLPFC and PPC (Buckner et al, 2011; O'Reilly et al, 2010). Given the importance of the cerebellum in motor control and learning, and the presence of cerebellar clusters of connectivity with the dPMC in the RSFC analysis, the absence of cerebellar clusters in the MACM analysis is perhaps surprising (though the MACM analysis did not identify the cerebellum as having functional connectivity with the dPMC, further analysis did identify multiple subthreshold clusters of cerebellar connectivity - see supplementary results).…”

Dynamic changes in prefrontal cortex involvement during verbal episodic memory formation

“…This approach has been used in previous rTMS studies (e.g., Berman et al, 2000;Fregni et al, 2006;Lesage, Morgan, Olson, Meyer & Miall, 2012). In addition, as one participant in the VLPFC group did not complete one block at retrieval, we opted for an approach that offers more statistical power in the presence of missing data.…”

Internal modeling of upcoming speech: A causal role of the right posterior cerebellum in non-motor aspects of language production

“…The idea of internal models has also been incorporated into theories and empirical investigations of language processing (Pickering & Garrod, 2013;Pickering & Garrod, 2014;Hickok, 2012;Lesage at al.,2012;Argyropoulos et al, 2011;2013;. In the domain of language production, certain theories propose that internal models are used to self-monitor (prevent and detect speech errors) some or all levels of our utterances.…”