Cerebri anatome: cui accessit nervorum descriptio et usus

Dissatisfied with the imperfect and fragmentary descriptions in earlier accounts of the brain, Willis devised a comprehensive and comparative program of brain dissections, which he carried out with the aid of his pupils Christopher Wren (1632-1723) and Richard Lower (1631-1691). Willis classified and described ten pairs of cranial nerves, six of which are still recognized, and was the first to grasp the physiological significance of the "circle of Willis," the circle of anastomosed arteries at the base of the brain by which full circulation to all parts of the brain can be maintained even when the carotid or vetebral arteries are blocked. From his observations of animal brains, Willis hypothesized that the convolutionary complexity of the human cerebral cortex is correlated with man's superior intelligence, and that the cerebellum, a similar structure in all mammals, is the source of involuntary action. This work is also thought to contain the first use of the term "neurology."