The cerebellum is emerging now as the dark horse of brain science. Dismissed as a less important part of the brain that controls motor functions, the cerebellum has not been given the attention it deserves for decades. However, a study published in the journal Neuron on the 25th finds that the cerebellum has a key role in the higher functions of the brain such as attention, thinking, making plans and decisions. The cerebellum acts as the brain’s final quality control unit, says Scott Marek, lead author of the work and member of the team from Washington University School of Medicine in St. Louis that conducted the research.
There are neurologists like Dr. Jeremy Schmahmann, professor of neurology at Harvard, who have been arguing for decades that the cerebellum is not just involved in the motor functions in humans and that it is involved in almost everything they do. Using the functional connectivity MRI scan, Marek and team tried to get wiring maps of individual brains. The team identified the network of the cerebellum and found that only 20 percent of it is used for controlling motor functions. The remaining parts (80 percent) are used for functions connected with higher order cognition. This includes the attention network, the default mode network (DMN) which is involved in activities like daydreaming, idle thinking and going back to memories, and also the brain networks that take care of activities like making plans and decisions.
Marek says that the cerebellum doesn’t directly carry out tasks like thinking, nor does it control movements directly. Its function appears to be that of monitoring the brain areas that carry out different activities and help them perform better, constantly reviewing and suggesting improvement. Dr. Nico Dosenbach, in whose lab the study was conducted, says that this could explain the way alcohol affects the brain. Alcohol doesn’t just don’t affect people’s physical movements; it often makes them take bad decisions and this is because the cerebellum is not functioning properly. The study also led the team to surmise that the cerebellum evolved through millions of years, which allowed it to expand enormously. It is the extra capacity that allowed it to handle functions other than movement.