Functional Role of the Cerebellar Vermis in Emotional Processing in Bipolar Disorder

The cerebellum, classically known for coordinating motor movements, has been found to play a role in cognitive integration, time perception, executive control and modulating mood. The vermis has been labeled as the limbic cerebellum based on its anatomical connections and the behavioral sequelae of individuals with cerebellar lesions. Studies suggest that individuals with bipolar disorder demonstrate decreased size of the cerebellar vermis when compared to healthy individuals, in particular in the superior posterior vermis (area V2), vermal area 3 (V3) and the flocculonodular vermal areas. Clinical variables, such as the number of prior affective episodes, age, family history of bipolar disorder and number of depressive episodes have also been found to correlate with vermal size. Additional studies found lower cerebellar blood volumes in individuals with bipolar disorder compared to healthy controls. Despite these reports, however, little is known regarding the functional role of the cerebellum, if any, with respect to bipolar disorder. Nonetheless, the reported structural and clinical abnormalities of the vermis suggest that an exploration of the vermis’ functional role in the modulation of mood might contribute to our understanding of bipolar disorder. The present study explored the role of the cerebellar vermis during emotional processing in order to integrate this role into models of bipolar disorder. We hypothesized that in healthy individuals the cerebellar vermis helps to manage emotional (ventral) networks, similar to the role of the cerebellar hemispheres in motor control. From this hypothesis, we predicted that the cerebellar vermis would be differentially functionally connected in healthy individuals and bipolar subjects in a manic mood state; i.e., that vermal dysfunction is associated with a manic mood state in bipolar disorder. Consistent with existing literature, functional connectivity to several areas associated with the ventral emotional network were associated with activation of the three vermal seed regions. We also found that functional connectivity to dorsal prefrontal regions was also more strongly correlated with the three vermal seed regions in individuals with bipolar disorder when compared to healthy subjects. Functional connectivity analyses also revealed active regions present in both the anterior limbic network (ALN) and cerebellar vermis during task processing, specifically, the parahippocampal gyrus and cingulate gyrus. While we have gained a clearer understanding that these regions are functionally connected, we are still unclear of how these regions interact. Such an understanding can aide in the development of non-traditional uses for technologies such as deep brain stimulation and deep repetitive transcranial magnetic stimulation. Future studies need to address the directionality of the relationship, if any, between these regions.

Name thesis:degree_name

PhD

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Arts and Sciences: Psychology

Grantor dc:publisher

University of Cincinnati

Year dc:date

2012

Author dc:creator

• Madore, Michelle R.

Contributors dc:contributor

• Strakowski, Stephen

• Psychology
• Neuropsychology
• fMRI
• Bipolar Disorder

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=ucin1352403019

OAI identifier oai:identifier

oai:etd.ohiolink.edu:ucin1352403019