Reflections on the neuroscientific legacy of Jaak Panksepp (1943–2017)

One of the truly great voices in modern neuroscience was silenced recently, when Jaak Panksepp suddenly died on April 18th of this year, following a fairly routine surgical procedure that went badly awry, generating a serious ischemic-hypoxic insult, a tragedy from which not even Jaak Panksepp could recover. Jaak had battled long and hard with recurring bouts of several cancers, and as is too often the case, it was actually the cancer therapy process that eventually killed him and not the cancer itself, although that distinction offers little solace. Nevertheless, the terrible and final suddenness of all this, despite Jaak’s age and medical history, was shocking and deeply upsetting to all of us who were close to Jaak. None of us is truly prepared for these departures at the end of life, even though we all know that they are coming eventually, and inevitably. Jaak’s neuroscientific work was, as many now appreciate, centered at least in part around separation distress as a prototype emotional state. He has had much to say, over the many years of his career, about the nature of the very grief that all who knew Jaak well have been feeling since his passing. That grief still lies heavy on many hearts, of family, friends and colleagues. The personal and professional losses for me are almost impossible to separate, as I lost a senior colleague, a highly valued friend, and a mentor in neuroscience, who was decisively the largest and most positive single influence in the second half of my professional career. But neuroscience as a field has also lost at least as much – an irreplaceable leader, a brilliant scholar and scientist, and a most passionate advocate for an affect-centered viewof the brain and mind. I take solace in my sense of great good fortune for having had 20+ years of close colleagueship and friendship with Jaak, sharing half a dozen week-long Affective Neuroscience seminars, many book chapters, dozens of larger conferences, and many other fruitful and sundry projects. I believe that over time, his intellectual legacy and its many gifts to the multiple sub-fields of mind and brain science will prove increasingly resonant and prescient, guiding generations of young scientists and clinicians. Progress in science is intrinsically slow by its very nature. But once in a while, a highly creative genius comes along, whose insight and integration of large amounts of previously fragmented material, creating new paradigms and concepts, moves the field forward in sudden and deceptive leaps. In the increasingly “twinned” fields of neuroscience and psychology, Jaak was one of those people. By any conventional standard of scientific productivity, he was a giant contributor to the neuroscience of emotion and was staggeringly prolific, with over 450 empirical and review publications, and literally many dozens of book chapters in various edited volumes and compilations. His publication vitae centrally featured his 1998 textbook, Affective Neuroscience, increasingly regarded as a landmark work and a classic publication in neuroscience. This magnum opus was updated in the less technical and more accessible treatment, The Archaeology of Mind, co-authored with Lucy Biven (Panksepp and Biven, 2012). He also solo edited the well-regarded twovolume Advances in Biological Psychiatry in 1995– 1996 (Panksepp, 1995, 1996), the more recentTextbook of Biological Psychiatry in 2004, and the highly technical compilation Handbook of the Hypothalamus with Peter Morgane, in four volumes (1979, 1980a, 1980b, 1981), where one could first see the flowering of Jaak’s powerful intellect and his encyclopedic grasp of neuroscience. Very few have read this particular four volume compilation on the hypothalamus, but despite its age, it is still to this day the most comprehensive collection of work on that critically important neural system and its complex functional networks, which are unquestionably central to emotion as well as homeostasis (the importance of the hypothalamus for emotion likely deriving from howhomeostasis provided the evolutionary foundations for emotion). The very last of his many