Neurodevelopment - brain development
The central nervous system develops from a specialised region of ectoderm called the neuroectoderm.
The embryonic brain is divided into three areas:-
The prosencephalon separates into the diencephalon (prethalamus, thalamus, hypothalamus, subthalamus, epithalamus, and pretectum) and the telencephalon (cerebrum). The cerebrum consists of the cerebral cortex, underlying white matter, and the basal ganglia.
The mesencephalon comprises the tectum (or corpora quadrigemina), tegmentum, the ventricular mesocoelia, and the cerebral peduncles, as well as several nuclei and fasciculi.
The rhombencephalon includes the medulla, pons, and cerebellum. The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomeres. In the human embryo eight rhombomeres can be distinguished, from caudal to rostral: Rh7-Rh1 and the isthmus (the most rostral rhombomere). Rhombomeres Rh7-Rh4 form the myelencephalon (later becoming the medulla oblongata, a caudal portion of the fourth ventricle, and portions of the cranial nerves VIII, IX, X, XI, XII) and rhombomeres Rh3-Rh1 form the metencephalon (later becoming the pons, cerebellum, a portion of the fourth ventricle, and portions of the cranial nerves V, VI, VII, VIII)
The embryonic brain is divided into three areas:-
- Forebrain (prosencephalon) which is subdivided into the telencephalon and diencephalon
- Midbrain (mesencephalon)
- Hindbrain (rhombencephalon) which is subdivided into the metencephalon and myelencephalon
The prosencephalon separates into the diencephalon (prethalamus, thalamus, hypothalamus, subthalamus, epithalamus, and pretectum) and the telencephalon (cerebrum). The cerebrum consists of the cerebral cortex, underlying white matter, and the basal ganglia.
The mesencephalon comprises the tectum (or corpora quadrigemina), tegmentum, the ventricular mesocoelia, and the cerebral peduncles, as well as several nuclei and fasciculi.
The rhombencephalon includes the medulla, pons, and cerebellum. The rhombencephalon can be subdivided in a variable number of transversal swellings called rhombomeres. In the human embryo eight rhombomeres can be distinguished, from caudal to rostral: Rh7-Rh1 and the isthmus (the most rostral rhombomere). Rhombomeres Rh7-Rh4 form the myelencephalon (later becoming the medulla oblongata, a caudal portion of the fourth ventricle, and portions of the cranial nerves VIII, IX, X, XI, XII) and rhombomeres Rh3-Rh1 form the metencephalon (later becoming the pons, cerebellum, a portion of the fourth ventricle, and portions of the cranial nerves V, VI, VII, VIII)
