Dynamic inferior olive activation in a cognitive task: an fMRI study

The inferior olive provides powerful inputs to the cerebellum hypothesized to support cerebellar learning and error detection. Given cerebellar involvement in verbal working memory and the close interplay with the inferior olive, the inferior olive is likely also involved in verbal working memory. In order to elucidate the inferior olive's role in verbal working memory, we utilized an MRI-based Sternberg verbal working memory task which involved learning novel vs repeated sequences. As hypothesized, inferior olive activation was stronger during encoding and retrieval compared to maintenance, especially for novel compared to repeated sequences, indicative of diminished inferior olive activity with stimulus repetition. Results also revealed differential inferior olive activation during retrieval, with increased activation on matching probes for novel and on non-matching probes for repeated sequences. This underlines the crucial role of the inferior olive in novel information encoding and error feedback, and that conditions triggering strong inferior olive responses can change as a function of novelty.