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Cerebellum, the so-called little brain. (Collection of recent studies etc)


Alex84 Franz
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Alex84 Franz

There is more and more evidence of the higher role of the cerebellum, the so called little brain.

Ref1:

....This was accomplished by Azevedo et al. (2009) , who found that the adult male human brain, at an average of 1.5 kg, has 86 billion neurons and 85 billion non-neuronal cells – numbers that deviate from the expected by 7 and 24% only.** The human cerebral cortex**, with an average 1233 g and** 16 billion neurons**, is slightly below expectations for a primate brain of 1.5 kg, while the **human cerebellum**, at 154 g and** 69 billion neurons**, matches or even slightly exceeds the expected (Table 2 ).
..
https://www.frontiersin.org/articles/10.3389/neuro.09.031.2009/full

Ref2:
The human cerebellum has almost 80% of the surface area of the neocortex
The cerebellum has long been recognized as a partner of the cerebral cortex, and both have expanded greatly in human evolution. The thin cerebellar cortex is even more tightly folded than the cerebral cortex. By scanning a human cerebellum specimen at ultra-high magnetic fields, we were able to computationally reconstruct its surface down to the level of the smallest folds, revealing that the cerebellar cortex has almost 80% of the surface area of the cerebral cortex**. By performing the same procedure on a monkey brain, we found that the surface area of the human cerebellum has expanded even more than that of the human cerebral cortex, suggesting a role in characteristically human behaviors, such as toolmaking and language.**

https://www.pnas.org/doi/10.1073/pnas.2002896117

 

What does that mean? Is there support to this higher role? 

Ref3:

Functional boundaries in the human cerebellum revealed by a multi-domain task battery
There is compelling evidence that the human cerebellum is engaged in a wide array of motor and cognitive tasks. A fundamental question centers on whether the cerebellum is organized into distinct functional subregions. To address this question, we employed a rich task battery designed to tap into a broad range of cognitive processes. During four functional MRI sessions, participants performed a battery of 26 diverse tasks comprising 47 unique conditions. Using the data from this multi-domain task battery, we derived a comprehensive functional parcellation of the cerebellar cortex and evaluated it by predicting functional boundaries in a novel set of tasks. The new parcellation successfully identified distinct functional subregions, providing significant improvements over existing parcellations derived from task-free data. Lobular boundaries, commonly used to summarize functional data, did not coincide with functional subdivisions. The new parcellation provides a functional atlas to guide future neuroimaging studies.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8312478/

 

An 'Atlas: as stated there:
nihms-1720742-f0005.jpg

 

What does that mean?

There is more and more evidence, in this field, that the role of the cerebellum could have been massively underestimated.

Ref4:

Human cerebellum and corticocerebellar connections involved in emotional memory enhancement
Enhanced memory for emotional stimuli is crucial for survival, but it may also contribute to the development and maintenance of fear-related disorders in case of highly aversive experiences. This large-scale functional brain imaging study identifies the cerebellum and cerebellar–cerebral connections involved in the phenomenon of superior memory for emotionally arousing visual information. These findings expand knowledge on the role of the cerebellum in complex cognitive and emotional processes and may be relevant for the understanding of psychiatric disorders with aberrant emotional circuitry, such as posttraumatic stress disorder or autism spectrum disorder.
https://www.pnas.org/doi/10.1073/pnas.2204900119

 

pnas.2204900119fig01.jpg
Out of the 29 remaining ROI (Regions of Interest) s, 28 were located in neocortical and subcortical regions of the cerebrum and one was in the cerebellum

Also, interesting:

Ref5:


Reverse-translational identification of a cerebellar satiation network
The brain is the seat of body weight homeostasis. However, our inability to control the increasing prevalence of obesity highlights a need to look beyond canonical feeding pathways to broaden our understanding of body weight control1–3. Here we used a reverse-translational approach to identify and anatomically, molecularly and functionally characterize a neural ensemble that promotes satiation. Unbiased, task-based functional magnetic resonance imaging revealed marked differences in cerebellar responses to food in people with a genetic disorder characterized by insatiable appetite. Transcriptomic analyses in mice revealed molecularly and topographically-distinct neurons in the anterior deep cerebellar nuclei (aDCN) that are activated by feeding or nutrient infusion in the gut. Selective activation of aDCN neurons substantially decreased food intake by reducing meal size without compensatory changes to metabolic rate. We found that aDCN activity terminates food intake by increasing striatal dopamine levels and attenuating the phasic dopamine response to subsequent food consumption. Our study defines a conserved satiation centre that may represent a novel therapeutic target for the management of excessive eating, and underscores the utility of a ‘bedside-to-bench’ approach for the identification of neural circuits that influence behaviour.
https://www.nature.com/articles/s41586-021-04143-5

 

Ref6:

The cerebellum and psychological trauma: A systematic review of neuroimaging studies

Highlights:
•Structural and functional cerebellar alterations have been associated with exposure to early adverse experiences.

•Altered cerebellar connectivity with nodes of macroscale brain networks, including the salience network, the default mode network and the central executive network, was associated with trauma-related psychiatric symptoms.

Cerebellar alterations have been found in a variety of psychiatric disorders, including psychotic disorders (Brady et al., 2019), mood disorders (Lupo et al., 2019) and addiction (Miquel et al., 2016) and emerged as the most important predictive feature of general psychopathology in adolescents (Moberget et al., 2019). Recent research suggests a substantial overlap in neural signatures of common mental disorders, pointing towards a shared risk for psychopathology (Vanes and Dolan, 2021). For this reason, during the past years, there has been a progressive shift towards a dimensional approach of psychiatric disorders, across diagnostic boundaries (Insel et al., 2010). Interestingly, structural alterations in the cerebellum have been associated with a general liability for common mental disorders (Romer et al., 2018), although the exact mechanism of cerebellar involvement in psychiatric disorders is yet to be discovered.

https://www.sciencedirect.com/science/article/pii/S2352289522000042

 

Ref7:


Linking cerebellar functional gradients to transdiagnostic behavioral dimensions of psychopathology

Highlights

Linking cerebellar functional gradients to transdiagnostic behavioral dimensions of psychopathology.


Associations between patterns of cerebellar connectivity gradients and behavioral measures could be represented into four latent dimensions.

Abstract
High co-morbidity and substantial overlap across psychiatric disorders encourage a transition in psychiatry research from categorical to dimensional approaches that integrate neuroscience and psychopathology. Converging evidence suggests that the cerebellum is involved in a wide range of cognitive functions and mental disorders. An important question thus centers on the extent to which cerebellar function can be linked to transdiagnostic dimensions of psychopathology. To address this question, we used a multivariate data-driven statistical technique (partial least squares) to identify latent dimensions linking human cerebellar connectome as assessed by functional MRI to a large set of clinical, cognitive, and trait measures across 198 participants, including healthy controls (n = 92) as well as patients diagnosed with attention-deficit/hyperactivity disorder (n = 35), bipolar disorder (n = 36), and schizophrenia (n = 35).
...

Very interesting. This 4 latent variables are
(Link to the visualization):

:
3.2. LV1: General psychopathology LV1 1-s2.0-S2213158222002418-gr1_lrg.jpg


3.3. LV2: Impulsivity and mood LV2 1-s2.0-S2213158222002418-gr2_lrg.jpg


3.4. LV3: Internalizing and less externalizing symptoms LV3 1-s2.0-S2213158222002418-gr3_lrg.jpg


3.5. LV4: Executive dysfunction LV4 1-s2.0-S2213158222002418-gr4_lrg.jpg

 

Discussion:
Although the importance of cerebellar function in mental health and disease is increasingly recognized, the degree to which cerebellar connectivity is associated with transdiagnostic behavioral dimensions of psychopathology remains largely unknown. Leveraging a unique dataset including resting-state fMRI and behavioral assessments spanning clinical, cognitive, and personality traits, we found robust correlated patterns of cerebellar connectivity gradients and behavioral measures that could be represented in four transdiagnostic dimensions. Each dimension was associated with a unique spatial pattern of cerebellar connectivity gradients, and linked to different clusters of behavioral measures, supporting that individual variability in cerebellar functional connectivity can capture variability along multiple behavioral dimensions across psychiatric diagnoses. Our findings highlight the relevance of cerebellar neuroscience as a central piece for the study and classification of transdiagnostic dimensions of psychopathology.

https://www.sciencedirect.com/science/article/pii/S2213158222002418#f0005

 

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