This research project is investigating the role of the cerebellum in language processing. The cerebellum, which is Latin for 'the little brain,' sits below the left and right hemispheres of the cerebrum (the largest and most commonly depicted part of the brain). While the cerebellum may be small, it is densely packed with brain cells, and it is thought to play a crucial role in motor control and learning. With funding from the National Science Foundation, Dr. Julie Fiez of the University of Pittsburgh is using functional brain imaging to identify specific regions in the cerebrum and cerebellum that are important for processing phonological (word sound), semantic (word meaning), and articulatory (speech production) attributes of spoken and written words. The research builds on evidence that portions of the cerebellum are expanded in humans, and that these newer portions of the cerebellum are interconnected with portions of the cerebrum that support human thought and language. But scientists still have a poor understanding of exactly how the cerebellum contributes to cognition, in part, because the prior research on this brain structure has focused mainly on its motor functions. This project is using cutting-edge brain imaging techniques to address the gap in current knowledge. A newly developed technique (diffusion weighted imaging) for studying the neural fiber pathways of the human brain is being used to determine whether regions with the same functional specializations are interconnected with each other, forming cerebro-cerebellar processing loops that are dedicated to different language functions. The research is being carried out with healthy young participants and then with participants who have a history of a stroke that has damaged part of their cerebellum. The project is examining whether damage to specific processing loops for language cause corresponding problems with specific types of language tasks.
The broader impacts of the research are diverse. First, the methods being used are still under development, and their use in this project provides an opportunity to validate them as research tools and to push the technology forward. These methods are a major scientific breakthrough, because until now there has been no suitable technique for studying, with high definition, the fiber pathways of the human brain. The specific application of these methods to the cerebellum is expected to have a significant impact. For more than 20 years scientists have speculated about what the cerebellum contributes to cognition, but the results across different research labs have been inconsistent, and existing theories are overly general. By gaining a more solid understanding of specific processing loops within the cerebellum, apparent discrepancies within the scientific literature can be resolved and more accurate and precise theoretical models can be developed. While the research is not directed towards a clinical application, it is important to note that the cerebellum has been implicated in several clinical disorders, such as autism, dyslexia, and schizophrenia. An increased understanding of the cerebellum's contributions to human thought and language could point the way towards more effective clinical diagnoses and treatments. The project is also providing an opportunity for undergraduate and graduate students interested in cognitive neuroscience to gain experience in this field of study, and efforts are being made to communicate the results to both the scientific community and lay audiences.
