Paper - The human brain at stages 18-20 including the choroid plexuses and the amygdaloid and septal nuclei (1990)

From Embryology
Embryology - 23 Jun 2024    Facebook link Pinterest link Twitter link  Expand to Translate  
Google Translate - select your language from the list shown below (this will open a new external page)

العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt    These external translations are automated and may not be accurate. (More? About Translations)

Müller F. and O'Rahilly R. The human brain at stages 18-20, including the choroid plexuses and the amygdaloid and septal nuclei. (1990) Anat Embryol (Berl). 182(3): 285-306. PMID 2268071

Online Editor 
Mark Hill.jpg
This 1990 paper by Müller and O'Rahilly uses the Carnegie Collection embryos to characterise the development of the ventricular system and choroid plexuses during the embryonic period. Note only a modified version of the abstract is shown online for educational purposes.

Also by this author: O'Rahilly R. and Müller F. Ventricular system and choroid plexuses of the human brain during the embryonic period proper. (1990) Amer. J Anat. 189(4): 285-302. PMID 2285038
PMID: 2268071 DOI: 10.1007/bf00185521

Modern Notes: ventricular

Neural Links: ectoderm | neural | neural crest | ventricular | sensory | Stage 22 | gliogenesis | neural fetal | Medicine Lecture - Neural | Lecture - Ectoderm | Lecture - Neural Crest | Lab - Early Neural | neural abnormalities | folic acid | iodine deficiency | Fetal Alcohol Syndrome | neural postnatal | neural examination | Histology | Historic Neural | Category:Neural

Historic Disclaimer - information about historic embryology pages 
Mark Hill.jpg
Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding.     (More? Embryology History | Historic Embryology Papers)

The Human Brain at Stages 18-20, including the Choroid Plexuses and the Amygdaloid and Septal Nuclei

Fabiola Müller
Fabiola Müller
Ronan O'Rahilly 1987
Ronan O'Rahilly (1987 Carnegie Labs)

Müller F. and O'Rahilly R.

Carnegie Laboratories of Embryology, California Primate Research Center, Davis.


The development of the human brain during the seventh embryonic week was studied in serial sections of 88 embryos, and graphic reconstructions were prepared. From stages 18, 19 and 20 the cerebral hemispheres expand rapidly and become more and more distinct entities. The longitudinal fissure between them occupies approximately half of their rostrocaudal extent.

In stage 20 they have progressed so far in organization that functional aspects (based on synapses in the primordial plexiform layer) are of importance. An advanced differentiation is also present in the amygdaloid body, which has at least four individual nuclei, and in the forebrain septum, which shows the nucleus of the diagonal band and the medial septal nucleus. This has a bearing on recent experimental studies that document the fundamental role of the septal nuclei with regard to behavioural and cognitive functions. Fibre connections between septal nuclei and hippocampus have appeared. A definitive internal capsule, however, is not yet present. The main connections with diencephalon and other parts of the brain are chiefly by fibres to or from the amygdaloid body by way of the lateral forebrain bundle.

The olfactory areas are connected with the habenular nuclei by a well developed stria medullaris thalami. Globus pallidus externus, entopeduncular nucleus, and subthalamic nucleus are prominent features in the subthalamus. The main nucleus of the oculomotor nerve shows a dorsolateral and a ventromedial portion. The rhombic lip is mitotically active in all parts of the rhombencephalon, and seems to participate significantly in the formation of the intermediate layer of the cerebellum and of the cochlear nuclei. The sensory nucleus of the trigeminal nerve has appeared. In the cerebellum the cell layer thought to contain the future Purkinje cells develops. The cerebellar plate is organized into external and internal bulges, and is now connected with midbrain and hindbrain through fibre bundles. The area thought to be the dentate nucleus and the supposed floccular region are especially rich in fibres.

The accessory olivary nucleus appears in stage 19, and accessory nuclei of the abducent and hypoglossal nerves are evident in stage 20. The choroid plexuses of the fourth and lateral ventricles have appeared. In view of their advanced features, the study of embryos of stages 19-21 becomes increasingly relevant to questions of tissue transplantation.

Cite this page: Hill, M.A. (2024, June 23) Embryology Paper - The human brain at stages 18-20 including the choroid plexuses and the amygdaloid and septal nuclei (1990). Retrieved from

What Links Here?
© Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G