Implications of cerebellar anatomy and functioning on fluid intelligence and the moderating effects of trait anxiety __________________________________________________
Summary
The role of the cerebellum in cognitive performance has started to be investigated in recent years. In particular, experimental data of healthy subjects points towards contributions of Crus I and II in inductive reasoning and problem solving. Data on populations with cerebellar lesions also finds implications of emotional responses, especially related to anxiety. This two-part study was made up of a dataset from the data-sharing website ABIDE and experimental data that was collected at Utrecht University in the form of a pilot study. In the first part a sample of 45 neurotypical University students were assessed on their cerebellar volumes using structural MRI and scores on the WISC were obtained. In the second part a different student sample received cathodal cerebellar transcranial direct current stimulation (tDCS) while performing the Raven Progressive Matrices (RPM) test. Results of the first study showed no associations between inductive reasoning and Crus I and Crus II volumes as well as total cerebellar volume. There was also no effect of cerebellar tDCS on RPM performance test and participant’s reaction times on the RPM. Trait anxiety was assessed to explore its role in the effects of tDCS on inductive reasoning using the STAI. There was no moderating effect of trait anxiety on the relationship between cerebellar disruption through transcranial stimulation and scoring on the Matrices task. The current studies do not provide evidence that cerebellar volume size affects fluid intelligence and that cerebellar tDCS interferes with inductive reasoning. These findings are discussed with regards to the literature and implications for future research.