At the turn of the 20th century, British physiologists Charles Scott Sherrington and Albert Sidney Frankau Leyton started poking around in the brains of anesthetized great apes in their lab at the University of Liverpool to see what would happen. While their work would never secure the necessary permits in any laboratory today, the data they generated is in every modern neurobiology textbook, albeit in simplified form.

The researchers examined the brains of 22 chimpanzees, three orangutans, three gorillas, and a handful of other animals under deep anesthesia induced by chloroform and ether. Applying mild electrical stimulation to the cortex, they revealed that the control of certain body parts was localized to particular brain regions—a hotly debated topic at the time.

“There had been a lot of arguments about whether functions are localized,” says Roger Lemon, a neurophysiologist at University College London. While cortical stimulation had been shown to elicit motor responses in dogs and rabbits, “there were people who were saying it’s not possible to get these same effects in primate brains.”

Sherrington and Leyton evoked cortical responses that were quite complex, sometimes including several consecutive movements. In all, they documented 400 different “first movements”—the initial motor response to a given stimulus—and charted the most complex motor map ever created, published in the Quarterly Journal of Experimental Physiology in 1917. “The paper is famous for the fact that it represents the first systematic mapping of the primate brain,” says Lemon. “It was a very big step forward.”

The figure shown here is a simplified map of the cortex that summarizes the evoked movements into broad categories of body area. Stimulation to the area labeled “leg,” for example, would result in a variety of leg movements depending on the exact location of the electrode.

None wants to underscore the clinical analysis of a patient. As a neurologist I understand how it is important to collect as many data as possible from patient history and neurological examination. Nevertheless I think that there are no other clinical branches where a deep knowledge of physiology and anatomy is extremely helpful in understanding the origin of the pathological symptoms. This knowledge certainly was improved by the accurate analysis of the patients when still alive as well as post-mortem (I recall you the Broca's patient). However I still remain in my opinion that without the accurate and defined data obtained from animals, we could not obtain the advancement in both knowledge and treatment of today neurologic patients. Certainly, if Sherrington should live in our days, he probably would utilize a CT scan or an fMRI for his studies....But this is not science. It's fiction.

Of course there had been cases of people recovering (to varying extents) from brain injuries before the work of Leyton and Sherrington, but their work examined the phenomenon far more precisely than had previously been possible, just as their mapping of functions within the cortex was far more precise than earlier efforts.

LINK

Their study paved the way for future research using electrostimulation (and later deep brain stimulation) on both human subjects and animals, its influence was immense because it was so very useful and informative.

Oh well, I suppose there will be those in a hundred years time who will claim that Gail Martin and Shinya Yamanaka made little contribution to stem cell medicine.

I disagree with Paul Browne and Aram Megignian. Human patients' recovery of function after brain injury was, has been, and is best demonstrated by human patients' recoveries after brain injuries. It seems bizarre and almost occult to suggest that such recovery did not occur in humans until Sherrington, Leyton and others demonstrated the phenomena experimentally in monkeys.

I agree with the comment of P.Browne and disagree with the comment of R.Bogle. I think that these specific studies of Sherrington as well as his studies on the spinal reflexes, gave origin to a lot of knowledge succesfully utilized in managing neurologic patients. I would only recall the studies of Penfield on the same cortical areas in humans undergoing neurosurgical treatments. Practically all the background knowledge today utilized by neurosurgeons in approaching a neurosurgical treatment is deriving from these pioneer studies.
Generally speaking I think that any kind of scientific and technological advancement can be achieved only through basic science studies. It is difficult for basic scientists to "justify" their studies, I agree. But even the file of all basic science discoveries and new technical approaches to arrive to these discoveries is so long that it is impossible not to recognize it.

You have missed a very important aspect of Sherrington and Leyton's work, namely their demonstration that the brain could recover a large degree of function after lesion. This, and other research carried out by Sherrington, eventually lead to work by scientists including Edward Taub who revolutionized the treatment of stroke patients.

LINK

Sherrington's work may have been what is now termed "basic" research, but it informed and underpinned a lot of the advances we have seen in the treatment of neurological disease and injury over the past century.

As interesting as this work was, like the number of moons around Saturn, it did not result in an advance in medical treatment.

What they also showed was the greater representation of certain areas such as the tongue and lips

You are correct that Ferrier and others did indeed make maps of the primate brain prior to the one by Sherrington and Leyton pictured here. Sherrington and Leyton refined the techniques used previously, however, to create this first *detailed* map of the primate motor cortex. Please refer to Dr. Roger Lemon's "An enduring map of the motor cortex" (LINK for more detail on the work performed by Sherrington and Leyton and a comparison of their work with those that came before them.

Leyton and Sherrington may have been the first to map the brains of apes, but they were not the first to map the brains of primates. This was done some decades earlier by David Ferrier.

For references, see:
Heffner, H. E. (1987). Ferrier and the study of auditory cortex. Archives of Neurology, 44, 218-221. Available online at: LINK