Update cerebellum and cognition

Abstract:
There is now robust evidence that the cerebellum—apart from its well-established role in motor control—is crucially involved in a wide spectrum of cognitive and affective functions. Clinical and neuropsychological studies together with evidence from anatomical studies and advanced neuroimaging have yielded significant insights into the specific features and clinical relevance of cerebellar involvement in normal cognition and mood.

Introduction
...
The cerebellar cortex shows a complex and remarkably homogeneous cellular organization that is repeated across its entire extension. On the other hand, each part of the cerebellar cortex has specific feedforward and feedback connections to the cerebral cortex that go far beyond the long known connections to motor and premotor cortical areas. Indeed, there are parallel connections to paralimbic and association cortices. Based on these observations, it is thought that the cerebellum performs a universal transform that is applied to different domains, i.e., motor, cognitive and affective. According to current view, the cerebellum—based on its ability to detect errors in performing motor and mental processes—is building internal models, which are crucial for optimizing these processes and the basis for cerebellar learning across contexts [1, 2].
..
Whereas dysfunction of motor and vestibular parts are associated with ataxia, dysfunction of cognitive and limbic parts are associated with the cerebellar cognitive affective syndrome (CCAS) that was first described in the early 90s by Jeremy Schmahmann [4].
..
Topography of cognitive functions in the cerebellum
..
Guell et al. [9] analyzed task fMRI data of the Human Connectome Project. Data from almost 800 human participants were included from a range of motor, working memory, language, social, and emotional tasks in the scanner. Language tasks activated primarily the right posterolateral cerebellar hemisphere, and spatial tasks primarily the left posterolateral cerebellar hemisphere. In the literature, however, lateralization of visuospatial functions is less clear within the cerebellum than language functions. Working memory, executive, social and emotional tasks were accompanied by activation of the posterolateral cerebellar hemispheres bilaterally [9]. In emotional tasks, activation was also found in the vermis. The vermis has known anatomical connections with the limbic system and has been referred to as “limbic cerebellum” [10]. Activations related to cognitive tasks were observed predominantly in lobule VII, with some extension into lobule VI. The most detailed map of motor and non-motor functions within the human cerebellar cortex to date has been published by King et al. in 2019. Their findings confirmed earlier observations that functional representations in the cerebellar cortex do not follow the boundaries of the cerebellar lobules. Furthermore, their findings indicate that the cerebellar cortex is organized in distinct functional subregions.

..
Cognitive and affective abnormalities in cerebellar patients
..
Since most subtypes of SCAs and other degenerative ataxias have significant extracerebellar pathology, studies of SCA6, are of great interest in furthering our understanding of cerebellar contribution to cognition because in this disorder the patients have an almost exclusive cerebellar pathology. Indeed, executive deficits involving inhibition of response and verbal reasoning, cognitive flexibility and abstraction have all been found in SCA6 [37, 38], whereas deficits seem to be more diverse and pronounced in multisystemic SCAs, such as SCA2 and SCA3 [37, 39].

..

Clinical relevance and perspectives
...
Detailed knowledge of the presence, severity, and individual course of CCAS in patients with cerebellar disease is crucial because the presence of a CCAS may have an impact on the daily life of patients and their families due to cognitive and neuropsychiatric abnormalities, including inappropriate behavior or impulsive actions
..
Conversely, the understanding of the role of the cerebellum in cognition and affect could provide clues for the treatment of mental illnesses like autism-spectrum disorders, affective disorders or psychosis spectrum disorders as well as Alzheimer’s disease and frontotemporal dementia.
Link zur Studie bei Springer