An examination of the cerebellum and its involvement in higher cognitive processes

Abstract

The presence of cerebellar activity in a wide range of cognitive functions examined within an increasing body of neuroimaging literature has consistently been observed. The present thesis sought to clarify the role of the cerebellum in higher cognitive functions through two studies. In Study 1, a meta-analytic approach, which employed the activation likelihood estimate method, was applied to a collection of 88 neuroimaging studies demonstrating cerebellar activations in higher cognitive domains involving emotion, executive function, language, music, timing, and working memory. The results provide a consolidation of information on cerebellar involvement accumulated in different cognitive tasks of interest and systematically identified similarities among the studies. In addition, inter- and intra-domain comparisons for the cognitive domains of emotion, language, and working memory were conducted. Task differences within the domain of verbal working memory were also examined by a comparison of the Sternberg with the n-back task, and an analysis of the differential components within the Sternberg task. Study 2 was motivated by an increasing body of neuroimaging evidence pointing to the involvement of the cerebellum and several key regions in an aspect of executive control, inhibition. Given the roles of these brain regions have remained relatively unclear, the study employed dynamic causal modeling (DCM) in order to understand the roles each region play as part of an extensive neuro-network. In particular, dynamic causal modeling (DCM) was used to understand the neural network that supports the inhibition sub-process in executive function. The left inferior frontal gyrus (IFG) and insula were found to be involved in the inhibitory process while the right IFG, caudate, and Crus 1 are involved in the facilitative process of the Stroop task.