The role of the cerebellum in emotional modulation: implications for the treatment of depression.

Abstract

The cerebellum is the brain structure which is generally associated with movement, coordination, and equilibrium. However, studies performed in the last three decades revealed its involvement in emotional processing and the development of neuropsychiatric disorders, with an emphasis on unipolar and bipolar depression and schizophrenia. Major depression disorder (MDD) is one of the most common mood disorders that has become one of the leading causes of disease in the world. It is a life-threatening disorder due to its prevalence with suicidal ideation and further comorbidities. Therefore, it is imperative to find clinical treatments that can minimize the impact of the disorder. The cerebellum has been associated with depression in multiple research setups at a structural, functional, and molecular level. Morphological cerebellar changes in the form of decreased cerebellar volumes and white matter aberrations are observed in patients suffering from MDD. Additionally, cerebellar activation is observed through imagining setups in patients compared to controls, denoting altered activity focused at the cerebellar levels. Lesion studies and cases of cerebellar damage have shown that patients display depression symptoms. This has been collaborated via neuronal stimulation, which shows that the excitatory stimulation of the cerebellum leads to an increase in positive mood, whereas inhibitory stimulation leads to a decrease in mood and inability to identify with emotions, typical of the MDD symptomology. The exact role of the cerebellum in the propagation of the disorder remains unknown, however, the recent data makes the cerebellum a structure of interest in MDD. Promising new studies have shown that the cerebellum could be used as an additional target for depression therapies, via the use of stimulation therapy or as a potential depression biomarker for a subset of MDD patients. Therefore, the cerebellum is a new yet exciting potential target for improved clinical treatments for depression.