Malpighi – Neural Development

Change of pace, today.

Many of my posts lately have been devoted to creativity and the visual arts. I am also working on an introductory volume of neuroanatomy with my colleague, Andrew Lautin, MD. Today’s post is about one of the early contributors to neuroanatomy.

Marcello Malpighi (1628 – 1694), was a 17th century Italian physician. Among his accomplishments were appointment to serve as personal physician to the Pope, honorary member of the Royal Society of London and many discoveries about living organisms through the use of the newly invented microscope.*

He is considered by many, the greatest embryologist since the time of Aristotle. Using a simple compound microscope, he was able to illustrate three stages of the development of the chick embryo. In 1673, he published three drawings of the early developmental stages of the nervous system.

Diagram: Three Chick Embryos circa 1673

The left figure shows the neural plate stage with prospective brain labeled D and the prospective brain stem, which will support the brain, labeled B. The prospective spinal cord is just below B ranging all the way to C. Below B the square shaped segments of tissue bordering the nascent spinal cord are somites, tissue clumps which provide muscle and connective tissue.

The middle drawing shows the single vessel from the left hand diagram, transformed into a three vesicle stage of the neural tube. These three vesicles or ventricles reveal the original continuity of the hollow ventricular system. In the middle picture are two outpocketings labeled (A) which will become the eyes.

The far right figure shows the five vesicles (ventricles). The maximum number of ventricles obtained is five: the endbrain ventricle is labeled E, consisting of two connected bulbs, one showing and the other hidden behind it; the interbrain vesicle is labeled D; one of the optic evaginations that becomes the optic cups is labeled F, with the second one hidden behind it as in E; the midbrain vesicle is labeled A; and the hindbrain vesicle is represented by B and C, known as the pons and medulla respectively.**

* Ellyard, D, Wood, A. Who Discovered What When New Holland Publishers 2006

** Figure legend adapted from Swanson, Brain Architecture (Understanding the Basic Plan, 1st edition, Oxford, 2003).

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