Multiple Origins of Oligodendrocytes in the Mammalian CNS.
Schematic presentation of the origin and migratory pattern of oligodendrocytes derived from the telencephalon and the spinal cord.
A. Sagittal (top) and coronal (midline) sections of the E13.5 developing mouse brain are shown. The medial (I), caudal-intermediate (II) and caudal (III) coronal sections are indicated by dashed yellow lines on the sagittal section. These coronal sections show the origin of the oligodendrocyte within the telencephalon. The oligodendrocyte precursor cells (OPCs) originate from the ventricular zone of the telencephalon in three distinct waves: OPC1 (pink and blue arrows) arise from the AEP and MGE, starting at E12.5; OPC2 (green and brown arrows) arise from LGE and CGE, starting at around E14.5; and OPC3 arise from the cortex, starting at birth. The early-born oligodendrocytes migrate into the cortex at E16 and postnatally mature into myelinating oligodendrocytes. Most of the early-born oligodendrocytes disappear after birth, thus the cortex-derived oligodendrocytes comprise the majority of the oligodendrocytes in the adult cortex.
B. In the developing spinal cord, 80% of the OPCs are generated from the ventricular zones of the ventral pMN domain (pink arrows), in process which begins at E12.5. A secondary wave of OPCs arises from the ventricular zones of the dorsal spinal cord within the dP3-dP5 domains.
Abbreviations: T, Telencephalon; D, Diencephalon; MB, Midbrain; HB, Hindbrain; Ncx, Neocortex; LGE, Lateral Ganglionic Eminence; MGE, Medial Ganglionic Eminence; AEP/POA, Anterior Entopeduncular/Preoptic Area; CGE, Caudal Ganglionic Eminence; OPC, Oligodendrocyte Precursor Cell; RP, Roof Plate; FP, Floor Plate;