1. History of Neurology Roger Sperry, PhD (1913 – 1994) May 1, 2017
KUMC Neurology Morning Report
Richard J. Barohn, MD
May 1, 2017

2. Roger Sperry, PhD (1913 – 1994) Biography
YEAR
ACHIEVEMENT
1913
Born in Hartford, CT
1935
Oberlin College, OH
Majored in English, but took Intro To Psychology
R.H. Stenson, who worked with William James
1937
Masters in Psychology; Oberlin College
1941
PhD in Zoology; Univ of Chicago
1942
Post Doc; Harvard with Karl Lashley and at Primate Research Center in FL
1946
Faculty in Dept of Anatomy at Univ of Chicago; Assistant then Associate
1954
Professor in Psychobiology at California Institute of Technology
Experiments with Joseph Brogden, MD & many others (Michael Gazaniga)

3. Split Brain Experiments, Lateralization of Brain Functions
In cats and monkeys first
Cut optic nerves in the eye, so left eye connected to left hem and right connected to right hem
Also cut corpus callousness
Taught to distinguish triangle from square with right eye covered
Then presented same problem with left eye covered
Showed left and right hemispheres functions separately when not connected by corpus callous

4. Split Brain Experiments, Lateralization of Brain Functions
In humans undergoing corpus callous splitting for intractable epilepsy
Present word to either left or right visual field
If presented to right visual field, image processing left hemisphere
If presented to left visual field (right hem) the patient could not report seeing the word, only left side of brain could articulate speech

5. Another Experiment
Presented on a object to the left visual field and a different object to the right visual field in split brain patients
The patients left hand under a partition and patients asked to draw with their left hand what they had been shown
Patients would draw what they had seen in left visual field, when shown what they had drawn would describe what had been shown in right visual field
Proved when corpus callosum was severed it breaks connection between left and right hemispheres, making them unable to communicate with each other.
Patients has no idea that the other hemispheres even exists
“indeed a conscious system in its own right, perceiving, thinking, remembering, reasoning, willing, and emoting, all at a characteristically human level, and.. both the left and the right hemisphere may be conscious simultaneously in a different, even in a mutually conflicting, mental experience that runs along in parallel” - Sperry 1974

6. Chemoaffinity Hypothesis
Nature vs. Nurture
Early experiments at U Chicago
Crosswire the motor nerves of rats legs so left nerve controlled the right leg and vice versa
Placed rats in a cage that had electric grid on bottom separated in to four sections
Each leg of the rat placed into one of the 4 grids
Shock administered to a specific section of the gird
Ex) the gird for rats left back leg would get a shock
So every time left paw was shocked the rat would lift its right paw and vice versa
Wanted to know how long it would take the rat to realize he was lifting the wrong paw
Rats never learned to lift up the correct paw
Some things are hard wired and cannot be relearned
No adaptive functioning of the nervous system

7. Chemoaffinity Hypothesis
Experiments with Optics in salamanders with Lashley at Harvard
Sectioned nerves and rotated eye 180 degrees
Would vision be normal after regeneration, or would animal forever view world as “upside down” and right-left reversed?
If later was the case, means the nerves were guided back to the original sites of termination
Restoration of normal vision (seeing the world “right-side up”) would mean the regenerating nerves had terminated in new sites
But the animal reacted as though the world was upside down and reversed right to left
No amount of training could change the response
Evidence for nerve guidance by “intricate chemical under generic control” (1963) and the chemoaffinity hypothesis

8. Chemoaffinity Hypothesis
“The cells and fibers of the brain must carry some kind of individual identification tags, presumably cytochemical in nature, by which are distinguished from one another almost, in many regions, to the level of the single neurons.” - Sperry
“He suggested that gradients of such identification tags or retinal neuro an and on the target cell sin the brain coordinator lay guide the orderly projection of millions of developing retinal axons.” - Science 2009

9. Roger Sperry, PhD 1971 1979 1981 1989 California Scientist of The Year
Wolfe Price in Medicine
Albert Lasker Medical Research Award
1981
Nobe Prize in Physiology of Medicine
Shared with Hubel & Wiesel
1989
National Medal of Science
Nobel prize ceremony

10. “The great pleasure and feeling in my right brain is more than my left brain can find the words to tell you.” – Roger Sperry