Final answer:
The part of the cerebellum formed by white matter includes the middle cerebellar peduncle, superior cerebellar peduncle, and inferior cerebellar peduncle, which connect the cerebellum to the pons, midbrain, and medulla respectively.
Step-by-step explanation:
The part of the cerebellum that is formed by white matter includes structures known as the cerebellar peduncles. These peduncles are comprised of myelinated axons that connect the cerebellum to different parts of the brain stem. Specifically, the middle cerebellar peduncle (MCP), also referred to as the brachium pontis, is a large white-matter bridge that connects the pons to the cerebellar cortex and constitutes the major input to the cerebellum.
Other important white matter structures include the superior cerebellar peduncle (SCP), which represents the main output of the cerebellum to the red nucleus of the midbrain, and the inferior cerebellar peduncle (ICP), which connects the medulla to the cerebellum.