Ralph's 1984 Ph.D. thesis in the lab of Richard I. Birks revealed astonishingly large and long-lasting potassium conductance and sodium pump driven voltage changes that occur following bursts of action potentials in thin axons that model presynaptic nerve terminals.
[3] After completing his graduate studies at McGill on theoretical neuroscience of spiking behaviour in neural dendrites, Ralph moved to the Salk Institute where he began to focus on in vivo, behavioral neurophysiology of monkeys.
While at Rockefeller, Ralph nurtured a latent interest in theoretical studies of cortical visual processing and the rapidly emerging field of optical imaging of cortex, through collaboration with a pioneering group led by Amiram Grinvald.
In collaboration with the Salk Institute's Ed Callaway (head of the Callaway Lab for the study of the organization and function of cortical circuits) and UC Berkeley's Ehud Isacoff (whom Ralph trained in the Birks lab at McGill, leading to a lasting friendship), Ralph began to develop tools that enabled optical monitoring of activity from neurons in behaving animals.
In 2012 Siegel's first book and memoir, Another Day in the Monkey's Brain, was published, by Oxford University Press,[4] with the help of his lifelong friend and colleague, Dr. Oliver Sacks.