How social is the cerebellum? Exploring the effects of cerebellar transcranial direct current stimulation on the prediction of social and physical events

Abstract

Congenital or acquired cerebellum alterations are associated with a complex pattern of motor, cognitive and social disorders. These disturbances may reflect the involvement of the cerebellum in generating and updating the internal models that subserve-the prediction of sensory events. Here, we tested whether the cerebellar involvement in using contextual expectations to interpret ambiguous sensory sceneries is specific for social actions or also extends to physical events. We applied anodic, cathodic and sham cerebellar transcranial Direct Current Stimulation (ctDCS) to modulate the performance of an adult sample in two tasks requiring the prediction of social actions or moving shapes. For both tasks, in an earlier implicit-learning phase (familiarization), we manipulated the probability of co-occurrence between a particular action/shape and contextual elements, which could provide either strongly or moderately informative expectations. The use of these expectations was then tested when participants had to predict the unfolding of temporally occluded videos, in situations of perceptual uncertainty (testing). Results showed that in the testing, but not in the familiarization phase, cathodic as compared to anodic and sham ctDCS hindered participants' sensitivity in predicting actions embedded in strongly, but not moderately, informative contexts. Conversely, anodic as compared to sham ctDCS boosted the prediction of actions embedded in moderately, but not strongly, informative contexts. We observed no ctDCS effects for the shape prediction task, thus pointing to a specific involvement of the cerebellum in forming expectations related to social events. Our results encourage the exploration of rehabilitative effects of ctDCS in patients with social perception deficits.

The Human Cerebellum as a Hub of the Predictive Brain

“…Preliminary neuroimaging evidence suggests a possible role of the cerebellum in predictive functions in social cognition, as the violation of social norms (i.e., a process that requires to compute whether the action could be construed as a violation and, crucially, whether the action was intended) has been shown to elicit fronto-temporo-cerebellar activations ([ 35 ]; see also [ 36 , 37 ]). In line with this preliminary evidence, cerebellar tDCS has been demonstrated to modulate participants’ performance in predicting actions embedded in highly informative contexts [ 38 ]. Future studies are nevertheless still needed to probe cerebellar involvement in predictive processing across different aspects of social cognition, as well as whether cerebellar involvement in cognitive functions is based on the very same predictive computations operating for the motor domain (for preliminary evidence, see [ 39 ]).…”

Action and emotion perception in Parkinson’s disease: A neuroimaging meta-analysis

“…The posterior lobe (particularly lobules VI and VII) has been associated with language, spatial, executive, working memory, and social-affective tasks ( Stoodley and Schmahmann, 2010 ), rather than motor tasks ( Stoodley et al, 2012 ). The role of the cerebellum in social prediction and social perception in healthy participants has been recently supported by noninvasive brain stimulation (e.g., Ferrari et al, 2019a , Ferrari et al, 2019b , Ferrari et al, 2021 , Heleven et al, 2021 , Oldrati et al, 2021 ) and neuroimaging data (e.g., Heleven et al, 2019 , Schraa-Tam et al, 2012 , Van Overwalle et al, 2019a , Van Overwalle et al, 2019b , Van Overwalle et al, 2019c , Van Overwalle et al, 2020 ).…”

“…It is nowadays acknowledged that the cerebellum constructs internal models also for purely mental states, without movements or somatosensory feedback ( Leggio and Molinari, 2015 , Van Overwalle et al, 2019a , Van Overwalle et al, 2020 ). In this view, the posterior cerebellum may be involved in the processing of social stimuli by providing internal models of social interactions, thus allowing predicting/anticipating others’ behaviors in the social environment ( Van Overwalle et al, 2019a , Van Overwalle et al, 2019b , Oldrati et al, 2021 ). Recently, also data from neuropsychological studies in children with congenital ( Urgesi et al, 2021 ) and acquired ( Butti et al, 2020 ) cerebellar damage supported the role of the cerebellum in social prediction.…”

Disconnection from prediction: A systematic review on the role of right temporoparietal junction in aberrant predictive processing

“…In other words, when either priors or sensory information are given more/less precision they should, predictions about our reality may become less accurate. Predictive processing represents a revolution in cognitive neuroscience because, along with providing a global theory about how the brain works, encompassing also the cerebellum (Friston, 2010;Oldrati et al, 2021), it has laid the basis to interpret a variety of diseases as conditions deriving from aberrant predictive processing (Smith et al, 2021). From a theoretical point of view, any disruptions to a component of the model may cause a cascade of consequences leading to domain-general impairments.…”