Master of Science
Two decades of neuroimaging research suggests that the cerebellum is functionally involved in a range of cognitive and motor processes. However, missing from the literature is a comprehensive map detailing a clear functional organisation of the cerebellum. Previous studies have used a restricted task-mapping approach to localise task-specific functional activation to cerebellar lobules. However, this approach, which is often limited to one or two functional domains within individual subjects, fails to characterise the full breadth of functional specialisation within the cerebellum. To overcome this restricted task-mapping problem, we tested 17 subjects on a condition-rich task battery (61 task conditions) across 4 scanning sessions. We then adopted a bottom-up approach, which allowed us to characterise functional activations in terms of latent features, rather than tasks. In this way, we were able to describe a broad spectrum of heterogeneous activity patterns using 11 latent features (rather than 61 task conditions). In deriving a functional map, we found that functional boundaries did not coincide with a lobular assignment, challenging the validity of the standard lobular nomenclature. This work offers two novel contributions to the field. First, the task battery that we designed is the most comprehensive to date, making this work the veritable “look-up” table for functional topography of the cerebellum. Second, we show that functional and lobular boundaries do not align. Thus, we challenge the field to revise the standard lobular nomenclature, to include functional subdivisions. In addition, we encourage the community to use the rich dataset generated by this expansive task battery with the aim of advancing the field towards a unified and testable theory of cerebellar function.
King, Maedbh, "Navigating the "little brain": Comprehensive Mapping of Functional Organisation" (2017). Electronic Thesis and Dissertation Repository. 4882.
Available for download on Friday, August 30, 2019