The role of the basal ganglia and cerebellum in language processing

Abstract

The roles of the cerebellum and basal ganglia have typically been confined in the literature to motor planning and control. However, mounting evidence suggests that these structures are involved in more cognitive domains such as language processing. In the current study, we looked at effective connectivity (the influence that one brain region has on another) of the cerebellum and basal ganglia with regions thought to be involved in phonological processing, i.e. left inferior frontal gyrus and left lateral temporal cortex. We analyzed functional magnetic resonance imaging data (fMRI) obtained during a rhyming judgment task in adults using dynamic causal modeling (DCM). The results showed that the cerebellum has reciprocal connections with both left inferior frontal gyrus and left lateral temporal cortex, whereas the putamen has unidirectional connections into these two brain regions. Furthermore, the connections between cerebellum and these phonological processing areas were stronger than the connections between putamen and these areas. This pattern of results suggests that the putamen and cerebellum may have distinct roles in language processing. Based on research in the motor planning and control literature, we argue that the putamen engages in cortical initiation while the cerebellum amplifies and refines this signal to facilitate correct decision making.

Bilingualism at the core of the brain. Structural differences between bilinguals and monolinguals revealed by subcortical shape analysis

“…Nevertheless, our greater sample size, the fact that we focused on simultaneous (instead of early) bilinguals, and the use of a more sensitive technique for the analysis of subcortical morphology, likely explain the larger extent and bilaterality of our results. The role of this striatal structure in language production and perception is well documented (Bohland and Guenther 2006;Gil Robles et al 2005;Murdoch 2001;Oberhuber et al 2013;Riecker et al 2005;Seghier and Price 2010;Tettamanti et al 2005), including the monitoring and programming of speech articulations (Chan et al 2008;Dodel et al 2005;Garbin et al 2010;Klein et al 1994Klein et al , 1995Riecker et al 2002;Simmonds, Wise, Leech 2011) and the processing of phonological errors (Tettamanti et al 2005; see also Bitan et al 2005;Booth et al 2002Booth et al , 2007Houk 2005). Given the wider range of speech sounds managed by Catalan-Spanish bilinguals compared to Spanish monolinguals, it is reasonable to expect that the putamen will be more strongly recruited by the former group, which might have an effect at the structural level.…”

Social discounting involves modulation of neural value signals by temporoparietal junction

“…Seven participants had to be excluded from the PPI analysis because they did not show any individual activation above threshold in the TPJ ROI at P < 0.05, uncorrected. This exclusion criterion is the standard for identifying the location of corresponding activations in individual subjects as needed to extract time courses for connectivity analyses (39)(40)(41)(42). We created two PPI regressors by computing an interaction regressor between the normalized time series and the respective condition, i.e., one regressor for generous and one for selfish decisions.…”

The basal ganglia circuits, dopamine, and ambiguous word processing: A neurobiological account of priming studies in Parkinson's disease

“…Given the emphasis in this review on neural circuits, there is the possibility that studies investigating correlations of activation may shed light on the cooccurrence of neural areas during specific task performance, thus contributing to our understanding of integrated neural circuitry. Recently, Booth et al (2007) assessed the functional connectivity between the cerebellum and the basal ganglia during a rhyming judgment task using dynamic causal modeling techniques. Similarly, Stamatakis et al (2005) used interregional covariance analysis as a measure of functional connectivity in a judgment task for regularly and irregularly inflected word forms.…”