Oligodendrocytes are the myelinating cells of the CNS that enable formation of myelin and saltatory nerve conduction. Disorders of oligodendrocytes and white matter are associated with human newborn neurological injuries leading to Cerebral palsy (CP). Damaged myelin sheaths and oligodendrocytes (OL) can be regenerated in these conditions by oligodendrocyte precursor cells (OPCs) in a process called remyelination. But myelin repair often fails, contributing significantly to ongoing neurological dysfunction and disease progression, and can fail because of failed OPC migration/recruitment into lesions or from their failed differentiation into mature OL. We have recently shown that OPCs migrate around the CNS using blood vessels as the physical scaffold for their motility, identifying critical oligodendroglial-vascular interactions that determine OPC dispersal during development and disease. Images show OPCs migrating on blood vessels in both normal human brain development and in the newborn neurological injury Hypoxic Ischemic Encephalopathy, as well as an electron micrograph of human myelin sheaths.