Cerebellum been identified as important: (1) feedforward processing, (2) divergence and convergence, (3) modularity, and (4) plasticity. There is considerable evidence that the cerebellum plays an essential role in some types of motor learning. The tasks where the cerebellum most clearly comes into play are those in which it is necessary to make fine adjustments to the way an action is performed. There has, however, been much dispute about whether learning takes place within the cerebellum itself, or whether it merely serves to provide signals that promote learning in other brain structures. Most theories that assign learning to the circuitry of
Anterior median fissure of the medulla oblongata Anterior median fissure of the medulla oblongata The anterior median fissure (ventral or ventromedian fissure) contains a fold of pia mater, and extends along the entire length of the medulla oblongata: It ends at the lower border of the pons in a small triangular expansion, termed the foramen cecum. Its lower part is interrupted by bundles of fibers that cross obliquely from one side to the other, and constitute the pyramidal decussation. Some fibers, termed the anterior external arcuate fibers, emerge from the fissure above this decussation and curve lateralward and upward over the surface of the medulla oblongata to