c. AD 390) was a Christian philosopher, and the author of a treatise Περὶ φύσεως ἀνθρώπου or De natura hominis ("On Human Nature").
He based much of his writing on previous work of Aristotle and Galen, and it has been speculated that he anticipated William Harvey's discovery of the circulation of blood.
Nemesius was one in a succession of advocates, from Herophilus and Erasistratus onward, of the idea that different cavities of the brain were responsible for different functions.
Even his date is uncertain, though a rough indication is given by some internal evidence that points to a time after the Apollinarian controversy and before the strife that is connected to Eutyches and Nestorius (the second quarter of the fifth century).
Nemesius may be the same person as the pagan of the same name to whom Gregory of Nazianzus addressed four letters and a protreptic poem.
This doctrine, as a following of earlier platonic theory, identifies that all sensory perception were received in the anterior area of the brain.
This area was then later termed the sensus communis and is the region where all sensory perceptions were held in common.
This is the area that was responsible for controlling the judging, approving, refuting, and assaying of the sensory perceptions which are gathered in the lateral ventricles.
Nemesius believed that the faculties operated through the agent of an animal spirit produced after it had been carried through a network of arteries.
Nemesius' doctrine of ventricle localisation of mental functions was greatly acknowledged but was later attacked by Brengarioda Carpi, and then by Vesalius and Varolio in 1543 and 1573.
Then, in 743 John of Damascus incorporated extensive excerpts in his writing De fide orthodoxa, though without naming Nemesius as the author.
This erroneous attribution was common in the Middle Ages in the Syriac, Armenian, Greek and Arabic traditions, as well as in the Latin-speaking scholarly world of the West.