Question: What kind of scientist did both Paul Greengard and Eric Kandel serve as?
Context: First published in 1981 by Elsevier, Principles of Neural Science is an influential neuroscience textbook edited by Eric R. Kandel, James H. Schwartz, and Thomas M. Jessell.  The original edition was 468 pages; now on the fifth edition, the book has grown to 1747 pages.  The second edition was published in 1985, third in 1991, fourth in 2000.  The fifth and latest edition was published on October 26th, 2012 and includes Steven A. Siegelbaum and A.J. Hudspeth as editors.  It has been hailed as the "Bible of Neuroscience" having been co-written by the "Father of Neuroscience", Eric Kandel. Pietro De Camilli is an Italian-American biologist and John Klingenstein Professor of Neuroscience and Cell Biology at Yale University School of Medicine.  He is also an Investigator at Howard Hughes Medical Institute.  De Camilli completed his M.D. degree from the University of Milan in Italy in 1972.  He then went to the United States and did his postdoctoral studies at Yale University with Paul Greengard. Arvid Carlsson (born 25 January 1923) is a Swedish neuropharmacologist who is best known for his work with the neurotransmitter dopamine and its effects in Parkinson's disease.  For his work on dopamine, Carlsson was awarded the Nobel Prize in Physiology or Medicine in 2000, along with co-recipients Eric Kandel and Paul Greengard. Eric Richard Kandel (] ; born November 7, 1929) is an Austrian-American neuroscientist and a University Professor of biochemistry and biophysics at the College of Physicians and Surgeons at Columbia University.  He was a recipient of the 2000 Nobel Prize in Physiology or Medicine for his research on the physiological basis of memory storage in neurons.  He shared the prize with Arvid Carlsson and Paul Greengard. Daniele Piomelli is an Italian-born American scientist.  He studied neuroscience in New York City, with James H. Schwartz and Eric R. Kandel at Columbia University College of Physicians and Surgeons (PhD, 1983-1988) and later with Paul Greengard at the Rockefeller University (Post-doc, 1988-1990).  Two of his mentors (ERK and PG) received in 2000 the Nobel Prize for their contributions to medicine.  After working at the INSERM in Paris (1990-1995) and at the Neurosciences Institute in La Jolla (1995-1998) with Nobel Prize winner Gerald Edelman, he joined the University of California Irvine School of Medicine, where he is now Louise Turner Arnold Chair in Neurosciences and Professor of Anatomy and Neurobiology, Pharmacology and Biological Chemistry.  He is also founding director of the department of Drug Discovery and Development (D3) at the Istituto Italiano di Tecnologia in Genova, Italy. The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science is a book on neuroplasticity by psychiatrist and psychoanalyst Norman Doidge, M.D.  It features numerous case studies of patients suffering from neurological disorders and details how in each case the brain adapts to compensate for the disabilities of the individual patients, often in unusual and unexpected ways.  Interviews with the patients, clinicians, and research scientists involved in these studies make up a large portion of the contents.  Doidge uses examples of previous work carried out by neuroscientists such as Paul Broca, Sigmund Freud, Alexander Luria, Donald O. Hebb, Paul Bach-y-Rita, and Eric Kandel to show that the brain is adaptive, and thus plastic.  Through the case studies, Doidge demonstrates both the beneficial and detrimental effects that neuroplasticity can have on a patient, saying, "... neuroplasticity contributes to both the constrained and unconstrained aspects of our nature."  However, according to Doige, neuroplasticity "... renders our brains not only more resourceful, but also more vulnerable to outside influences." Paul Greengard (born December 11, 1925) is an American neuroscientist best known for his work on the molecular and cellular function of neurons.  In 2000, Greengard, Arvid Carlsson and Eric Kandel were awarded the Nobel Prize for Physiology or Medicine for their discoveries concerning signal transduction in the nervous system.  He is currently Vincent Astor Professor at Rockefeller University, and serves on the Scientific Advisory Board of the Cure Alzheimer's Fund, as well as the Scientific Council of the Brain & Behavior Research Foundation.  He is married to artist Ursula von Rydingsvard. Chris Chase (born Irene Greengard; January 12, 1924 – October 31, 2013), also known by the stage name Irene Kane, was an American model, film actress, writer, and journalist.  Her best-known role was in "Killer's Kiss".  She later wrote advice books and co-authored several celebrity autobiographies.  Her younger brother is Nobel Prize winner Paul Greengard. Dopamine receptor D, also known as D2R, is a protein that, in humans, is encoded by the "DRD2" gene.  After work from Paul Greengard's lab had suggested that dopamine receptors were the site of action of antipsychotic drugs, several groups (including those of Solomon Snyder and Philip Seeman) used a radiolabeled antipsychotic drug to identify what is now known as the dopamine D receptor.  The dopamine D receptor is the main receptor for all antipsychotic drugs. Michael Nehls (born October 20, 1962) is a German doctor of medicine, author and former cyclist.  From 1983 until 1989 he studied medicine at the universities of Freiburg and Heidelberg.  In 1997, he achieved his postdoctoral lecture qualification in molecular genetics.  Nehls authored over 50 scientific publications, two of which were published with the Nobel Prize winners Paul Greengard and Martin Evans.  In 2015, his work was honored by the American American Association of Immunologists as a "pillar of immunologic research" for leading investigators in the discovery of a key molecular switch required for the development of the adaptive immune system.
Answer: neuroscientist