If you would like to add your reminiscences, Email Brance {AT} jhu.edu

We gather to celebrate with joy and thanksgiving the life of Kenneth O. Johnson: joy that we were privileged to have him among us for the time we did; thanksgiving for the many contributions he made to our lives. Kenneth O. Johnson was tall and in youth heavily muscled, as became the VIKING he surely was. His parents emigrated in the 1930’s from Iceland to Canada where Ken was born in 1938. And their ancestors must have sailed in those long boats from Scandinavia to Iceland at some distant time. Thus Ken was a VIKING both in his genes and his love of adventure. I sometimes imagine that one of Ken’s ancestors sailed with Eric the Red to Greenland, and perhaps even to North America in 1100 – thus making KOJ the descendant of the oldest emigrants among us. EDUCATION and THE SPACE PROGRAM Ken’s family moved to Seattle with the onset of WWII. There he went through the public school system, and the University of Washington, BS in Electrical Engineering, 1961. The space program was beginning, and Ken became project officer in Satellite Orbit Estimation with the General Electric Company in Syracuse, New York, where in his spare time he earned a Master’s degree in Electrical Engineering from Syracuse University in 1965. I do not know what singular event in Ken’s life turned him in 1966 from a promising career in space science to neuroscience. Perhaps those who follow can clarify that point; he never spoke of it to me. Be that as it may, he appeared here at Hopkins as a graduate student in Biomedical Engineering (PhD, 1970), and in our course in Physiology for the first-year students of medicine. He immediately attracted our attention; he was first in the class. Now that was a major accomplishment – first in a class of extraordinarily able students, without the extensive background in biology many of them possessed. THESIS RESEARCH Ken came to do his thesis work in the Department of Physiology. We were then engaged in seeking correspondences between three variables: the sensory stimulus, the human or monkey detection of, rating, or discrimination between those stimuli, and the neural activity evoked in monkeys by them. We had had some success, but Ken detected an exception we had overlooked. That is, that while the psychometric function describing the human estimation of the intensity of vibratory stimuli is linear with stimulus amplitude, the responses of the relevant set of Pacinian afferent fibers are not – they increment in a series of step function. Ken set about to solve that problem, and he did so completely on his own; for Ken and I never in our lives did an experiment together. Ken did what had not been done before: he accomplished a reconstruction of the population responses of the Pacinian afferent fibers innervating the glabrous skin of the monkey hand to stimuli of increasing amplitudes. He showed that population size increased in linear correspondence with the stimulus amplitudes, and humans’ rating of them. He later made population reconstructions for the cooling and warming fibers innervating the glabrous skin of the hand. The first was a major achievement, made by a man his first effort in experimental neurophysiology. He later stated in a formal document: “My main research interest is in the representation and coding of sensory inputs in the activity of populations of neurons.” And indeed he followed this and related themes throughout his research life. THE AUSTRALIAN ADVENTURE After one year as a fellow, Ken became an Assistant Professor of Physiology and Biomedical Engineering. During two years he collaborated with Professor Ian Darian-Smith in studies of the peripheral neural mechanisms in the senses of warming and cooling. Darian-Smith was then called to the Chair of Physiology in Melbourne, Australia. In spite of all we could do, there was nothing for it but that Ken would go with him. I guessed then and believe now that it was that Viking sense of adventure that took him to Australia. But look what he brought back with him from Australia, his beloved wife Jenifer, who is here with us today. When I went to Melbourne in 1976 I discovered that Ken had in manuscript form what I consider the most important theoretical papers of that decade in Neurophysiology. In them he determined how one could establish correlations between behavior and neural activity, in these cases in detection and discrimination. These papers were not published until 1980, neglected by many, perhaps because of their very dense mathematical content. I immediately set about providing a pathway for Ken to return to Johns Hopkins. He rejoined the Department of Physiology in January of 1981, and he never left again, until last May. THE JOHNSON LABORATORY Ken created a wonderful laboratory, filled with instruments and methods of his own invention, and occupied by five or six of the finest postdoctoral fellows and graduate students. Perhaps some of them here today will tell you of the series of discoveries that flowed from this group, and established it was what I – and most observers – believe to be the finest and most productive laboratory of somatic sensory Neurophysiology in the world. I wish to comment on something else; Ken Johnson’s experimental style. It was essentially Popperian. The aim was to conjure up all hypotheses that even on the slightest chance could explain the experimental observations; then to test and reject them one by one, until one came upon one that could not be rejected – what Ken called “the last code left standing:” to accept that final hypothesis only provisionally, and to test it again in every possible way. Thus we have the distributed spatial coding for pattern, the peripheral edge inhibitory effect, the complex spatial and temporal relations of inhibitory fields in the postcentral gyrus, and a number of others not hitherto dreamed of. One other important characteristic: Ken was a forceful voice in scientific debate, yet I never heard him raise his voice, or make a discourteous remark to any person. THE MOVE TO SCHOOL AND UNIVERSITY RESPONSIBILITIES Ken’s mature judgment and his concern for others placed him in wide demand for school and university committees – the curse of the scientific life. He managed them all with his usual grace, and continued his active life in the laboratory until the very end. He became successively Director of the Bard Laboratories in the Department of Neuroscience in the School of Medicine, Scientific Director and then Director of the Mind/Brain Institute on the Homewood campus. He was heavily engaged in University affairs, particularly his dream of a University-wide program of research and training in Neuroscience, still in the gestative stage. It was with his usual courage and innovation that Ken faced his inevitable end. When I last saw him in the Washington Hospital some weeks before his death he spoke only of the future, and of his future, in brain research. That is how I shall remember him.

Vernon Mountcastle

I first met Ken Johnson in 1969 in Vernon Mountcastle's labs at Johns Hopkins: we worked together with Carole LaMotte until 1972 on primate thermoreceptors in primate skin. They were happy and productive years, during which I learned a lot from Ken. Ken's background was in the physical sciences, and he was enrolled as one of the first of the University's graduate students in Biomedical Engineering. His particular strengths were in developing quantitative models which allowed us to correlate behavioral and thermoreceptive fiber responses to incremental changes in skin temperature. This modeling provided a framework for examining the responses of synthesized populations of the responding warm and cold fibers in man and monkey. Ken was specially skilled in explaining his models to a statistical klutz, at a level that we could actually test in our experiments. Late in 1972 I moved back to Australia to the University of Melbourne, and was delighted when Ken decided to join me. We continued to work together through the 70s on the representation of tangible textured surfaces in the responses of populations of 'touch' afferents innervating the hand of the macaque. Ken returned to Johns Hopkins in 1980, and was subsequently appointed Director of the Mind/Brain Institute. Ken was a quietly-spoken modest man, and a great pleasure to work with when analyzing experimental data. Unfortunately, after 1980 our paths seldom crossed.

Ian Darian-Smith

I overlapped with Ken for 2 years, while I was a BME graduate student doing my thesis research in Bill Milnor’s lab in the Physiology Department. While Ken and I had many research discussion, the best times we had were in the cardiovascular modeling lab we set up for the medical students in Physiology course their first year. The model was a simple Windkessel model that we set up using Pace analog computers. There were about a dozen of these desktop sized devices that had to be programmed using external wires with banana plugs connecting the operational amplifiers. Resistances and compliances could be adjusted with calibrated potentiometers. The cardiac output was modeled with nonlinear elements that generated a square wave flow into the Windkessel. The class was dividing in many groups, and with each group doing the lab over the course of several weeks. The students did the “programming” and then worked with specific physiologic questions. The beauty of these models was that the solutions could be viewed in real time and were easily appreciated by even students who were not technically oriented. We did this model for two years. When I saw Ken last year, he reminded me of how much fun we both had with this model. We worked well together as a team and both learned a lot about modeling and teaching. And even better, our enthusiasm was universally appreciated by the medical students, most of whom had never even heard of analog computers. But they got into the simulations with enthusiasm, and at the end of the sessions, we received many personal thanks for a great lab. Unfortunately, when Ken left and I graduated, there was no one willing to take over this lab, and it was deleted from the course.

Wayne Mitzne Ph.D. in Biomedical Engineering at JHU in 1972 Currently Professor of Environmental Health Sciences, Biomedical Engineering, Pulmonary Medicine, and Anesthesiology at JHMI.

I am a former student in Ken’s lab. I did my master’s degree with him at Hopkins and he was one of the first people I knew since I came to the US. In my opinion, he is a brilliant scientist and a considerate and helpful mentor. I enjoyed working with him. I will miss him.

Hanzhang Lu, Ph.D. Assistant Research Scientist

Ken Johnson's ability to do scientific research and communicate the results was extraordinary. Phyllis and I had most enjoyable times with the Johnsons. Our heartfelt condolence to Jennifer.

Moise Goldstein

I was Ken’s BME master’s student from 1996-1998, completing a thesis and publication that correlated a fine sense of roughness to peripheral neural responses. What struck me about Ken to this day are both his piercing mind and easy-going nature. These are not always compatible characteristics, but he combines them with enjoyable results. Although indubitably I spent most of my hours in the lab on experiments, my favorite memories are of Ken, myself, and the folks from his labs -- other graduates and post-docs, lab techs and our machinist -- sitting around the table at lunch (Ken often having some tuna and hard Snyders pretzels) and holding great discussions that ranged from what was on NPR that morning to specific details of neuroscience. He and I had infrequent email correspondence after I graduated, usually after I noticed an interesting publication or when he updated me on goings-on in the lab. I was just going through our old emails and notice he signed all of them along the lines of “And, most of all, I hope life is treating you well.” I am so sad to hear of his passing. My condolences go to his wife and family.

Barbara Gibb, MSE in Biomedical Engineering at JHU in 1998 Currently Product Planning Manager of NeuroPace, Inc. located in Mountain View, California

I'll always remember Dr. Johnson for his kindness and his patience. He was a great mentor and always so encouraging. I hit a really rough patch while completing the program and Dr. Johnson kept telling me not to give up and to keep going. And now, thanks to him, I'm on the path to realising a dream.

Jasmine lew MS1 Pritzker School of Medicine

I was deeply saddened to learn recently of the death of Ken Johnson. Ken’s studies on the peripheral coding and central representation of cutaneous mechanosensory stimuli were pioneering, and remarkable for their experimental thoroughness and analytical rigor. We review his papers extensively in our graduate course in systems neuroscience because of the insights they provide about the processing of sensory information by the central nervous system and because they provide a splendid example of how good research should be done. Beyond his scientific accomplishments, however, Ken will be remembered by his many friends and colleagues for his keen intelligence, his soft-spoken nature, his humanity and his generosity. I first met Ken when he returned to Johns Hopkins from Australia, while I was a postdoctoral fellow with Apostolos Georgopoulos. At that time, we were recording the impulse activity of single neurons in the primary motor cortex of rhesus monkeys during reaching movements. It was clear to us that the broadly symmetrical directional tuning curves of individual neurons generated ambiguous information about the intended direction of arm movement. An unambiguous signal specifying movement direction had to be embedded in the distributed activity of populations of motor cortical neurons. Ken took an interest in this question and we had a number of stimulating discussions with him about our findings. His comments were insightful and most helpful as we worked to develop a simple formalism, now commonly known as the population-vector hypothesis, by which a single unambiguous directional signal can be extracted from the diverse patterns of activity of many neurons. I have been fortunate to consider Ken as a friend ever since, and will always remember him fondly as a superb scientist and as a truly gentle man. My condolences go to his wife Jennifer and his family.

John Kalaska, Département de physiologie, local 4129, Pavillon Paul-G-Desmarais, Université de Montréal

Ken was a good friend and colleague of mine for more than 35 years. I have so many memories of him on both a personal and academic level. But I will just mention a very few of the academically related memories that come immediately to mind. Ken was an excellent teacher -one might even say a guru of sensory neuroscience. For example, as he was reviewing a grant proposal at an NIH study section, one stood in awe of his grasp of the subject and his abilities to put each topic in the context of what will move the field forward. He would lean back and speak without notes, describing the present state of affairs, what was needed (in this sense he taught others with unrelated research interests) and how the particular proposal would or could have or did not fulfill this purpose. But the way he spoke, the clarity and logic, was impressive. One of the speech pathologists on the CMS study section used to tally (just for fun) all the errors of speech made by each reviewer. She said that he was the only reviewer who never made a single one. As a teacher he was always friendly and patient. He was really a nice guy. This is one of Carole LaMotte’s treasured memories. When Carole was beginning her career as a new graduate student in the Department of Physiology, she remembers one of many times when Ken came to her rescue. A variety of challenges faced her as a first year graduate student one of which was to build a monkey chair for a cortical recording experiment. Ken was the one who showed her how to cut plexiglass with a band saw, how to use a drill press and do so in a gentle, patient manner and sense of humor. Carole remembers that when she was a graduate student, working on her warm-fiber thesis, she would be busy dissecting warm fibers from the monkey nerve while Ken and Ian Darien-Smith would sit back, puffing on their pipes, and planning every detail of the experiment and calculating how many fibers would be needed to achieve one particular objective or another (sometimes after being holed up in Ian’s office for a few hours, one of them would run out and say “we need only 5 more warm fibers to finish this part”). This discussion went on for many years long after she finished her thesis! This due to the necessity of really doing the project the way it should be done: for example, obtaining a quantitative determination of how warm or cool fiber response properties could account for the astounding capabilities of humans to make subtle thermal discriminations. When Ken and I were both in the Physiology Department (1969+) we both had long thoughts about what exciting topics to explore in the somatosensory system. I would be thinking about something and wonder into his office and bring up the issue, i.e. how could one go about solving this problem and Ken would take up a note pad and start from fundamental things that we already know and then write down what we want to know and all the relevant parameters and then devise a logical strategy to find the answers. He was the clearest thinker I ever knew. Always seemed to have the forest in mind and yet see more trees than anyone else while never confusing the two. Here was a scientist, superbly trained and talented in applied mathematics and biomedical engineering, fully capable of doting on the complexities of every issue and applying as sophisticated an analysis as one might imagine. Yet he chose to simplify problems to make them tractable as he did in his unique and monumental studies of spatial form processing by the somatosensory system. For example, in his studies of the spatial resolution of the fingerpad, he did not study all the variables contributing to discriminations of spatial patterns but rather devised ingenious experiments that eliminated those variables that were not “spatial” such as sensory cues related to area, or displacement magnitude. This enabled him to answer the question as to which class of mechanoreceptive afferents could account for spatial resolution, independent of such extraneous cues. The development of a continuum mechanics model of the skin to predict stresses and strains at the mechanoreceptor terminals in relation to neuronal responses to patterned stimuli, or the use of the “spatial event plot” to model the responses of populations of afferents, based on responses of one afferent to lateral placements of the pattern in the receptive field: Both required such assumptions as homogeneity in properties of tissue and afferent responses, definitely not exactly true but used extremely effectively by Ken and colleagues as excellent first approximations. Similarly, he could have taken a broad and complex approach to the neural coding of surface roughness (imagine the physical variables that contribute to the roughness of wool fabrics). But his initial approach confined the problem to the roughness of discrete Braille-like elements that differed in size and spacing. In this way he could test specific hypotheses about temporal, intensive and spatial neural coding based on physical parameters that he could control. I am going to miss him very much. I often think to myself, “how would Ken approach this problem” and I will no longer have the pleasure of hearing his voice in casual conversation. But he has left a rich and brilliant legacy that I continue to think about and read and the field of sensory neuroscience is all the better for it.

Bob LaMotte Departments of Anesthesiology and Neurobiology Yale School of Medicine

I worked with Ken and Steve for my doctoral thesis from 1990 to 1995. I remember quite distinctly entering the graduate program at Johns Hopkins. I looked through the pamphlet on the potential advisors, chose two in my desired field, cardiovascular mechanics, and then found another faculty member interested in studying neural coding and spatial transformation of sensory inputs in the somatic sensory system. That sounded too fascinating to pass up. I began with Ken and Steve for my first rotation, and left a little more than five years later without working anywhere else. Ken's passion and enthusiasm for his work was always admirable, and his acuity in quantitative analysis of neural signals and coding was without peer in neuroscience. Several memories about Ken stick out in my mind. He had a small can of salmon and a Diet Coke for lunch just about every day. At one point the salmon only came packaged in large cans - twice as large as previously. That was quite disruptive. When Ken went to NIH study section he always took several 100 watt bulbs with him, as the hotels in which the study section were held were had poorly lighted rooms. Ken had great stories, always surpassing in amazement those of everyone else in the lab combined, whether he was discussing how to manually plot satellite orbits, working as a lumberjack on Kodiak Island, or neuroscience. Ken could perform three digit multiplication in his head faster than anyone I've ever met. At one point after we were sure Ken was hard at work on a manuscript for weeks, he emerged triumphantly from his office. Instead of a final draft, he had rewritten some ForTran subroutines essential for processing neural data. The manuscript subsequently went much faster. Ken would also take quantitative neural data analysis several degrees deeper than anyone else in the lab. Upon leaving, his students became the "go to" experts in analyzing neural data across the field of neuroscience. Ken's reputation among his peers was not always clear to us as students. At the last Stockholm meeting on somatosensation, it became quite clear. Ken acted not as a participant, but as a mediator and elder. In the decade since I left the lab, I've continued to work in sensory neuroscience. As I approach each project, I too find myself wondering what Ken would say if I took an analysis into his office and subjected it to his scrutiny. We've been in periodic contact over the years, and I was quite saddened to hear of the progression of his disorder. His passing will leave a void in neuroscience - there are really few individuals studying in experimental brain physiology with his strengths in theory and mathematics. And, as we all know, Ken was a kind, modest, and extremely likeable person, one I will miss deeply.

Dave Blake, PhD, Bard Laboratories 1995 Asst. Professor, Dept Otolaryngology, UCSF

Ken's passing came much too soon. He and I had known each other for 40 years. With Susan and Jenny, I had counted on the four of us growing old together. Ken and I first met when we were students in the fledgling Bioengineering program at Hopkins in the '60s. Like grad students everywhere, we got together for social events -- cheap ones. Our first children were born at that time and our daughter Kate, although she hasn't seen Lissa now for years, still refers to her as "separate sister." Indeed, Ken was indirectly responsible for Kate's birth. One double-date night, four of us yahooing, he made his old Volvo hit the edge of every paving stone and railroad track between dinner in Little Italy and a late bedtime in our respective flats, enough jarring to cause Susan's water to break. It was plain to see that Ken enhanced the lives of many. He was exuberant, articulate, ethical, and far too well informed. Susan and I learned a lot about life from Ken. He exposed us to single malt scotch. He taught me how many steps there were in the Empire State Building by insisting we run down them while our pregnant wives took the elevator. He drove us to become regular readers of the New York Times, because as everyone knows, without sufficient facts, it was impossible to reach even a draw in an argument with Ken. How many arguments did he eventually win by beginning with, "Well, yes, I see that, but..."? All students, of course, have heard or told war stories about the trauma of getting that degree. My favorite was Ken's description of his oral exam. He said that he hadn't thought he was at all nervous. However, after his successful performance, he rose from his chair, thanked all his interrogators, turned, and, with great strength of purpose, walked smack into a wall. Susan and I eventually moved to Seattle for a faculty position at the U. of WA. It was Ken who was responsible for our decision. At the time, there were two premier textbooks of physiology: one edited by Ruch and Patton in Seattle, the other, of course, by Bard and Mountcastle. Although the science in Seattle clearly was first rate, Susan and I were uncertain about the quality of life in the Great Northwest. Ken was a perfect resource because he had grown up in Washington State. He regaled us with stories about his summer experiences as a lumberjack and a fisherman, about teenage years driving jalopies up and down Mount Baker, about living on a houseboat during his UW years, and about wonderful, unspoiled terrain for hiking and skiing within an hour's drive of the city. We were convinced and have been here ever since. We saw less of Ken after our move to Seattle and then his to Australia. We exchanged news of the births of his Marin and our Margaret. Fortunately, because his family lived in Washington State, he usually stopped by to see us while visiting them. On one of those trips, he introduced us to his wonderful new wife, Jenny. Not surprisingly, Ken had chosen someone who was a superb partner, and the four of us hit it off immediately. With those two, breakfasts on the porch became gabfests, and visits to old haunts like the Pike Place Market, the Elliott Bay Book Store and the magnificent Olympic Peninsula were viewed with fresh eyes. We last saw the Johnsons together when, in the fall of 2004, they visited son, Ben, who was spending a year at Microsoft. Over the last 40 years, Ken became a great scientist, who made important contributions to the understanding of the neural basis of somethesis. I was happy for him, and I admired him tremendously. But Susan and I will remember and miss him most as the fine and dear person who was our friend.

Susan and Albert Fuchs Seattle, Washington

Ken was married to my sister, Jennifer (Jenny to us) and was one of the nicest people I have ever met. He was a very special person, " a good person", as he would say. He could explain almost anything to me without being patronizing or making me feel silly. I loved him dearly and will miss him very much

Cathy Lee Tasmania, Australia

I first got to know Ken Johnson well when the Bard Labs moved up to the Homewood Campus in the mid-1990s. Ken joined the Undergraduate Neuroscience Major Program Committee that I am also a member of almost immediately after he arrived. He shared with this committee his incredible depth and breadth of knowledge about neuroscience that contributed to the excellence of the major in a myriad of ways. I came to admire him the most based on how he handled himself during the interviews of prospective students for the joint BA/MS program in neuroscience. He was gentle and respectful but yet firm and critical. He challenged students to do their best without a hint of criticism or judgment that was personal in nature. He was a model as to how a mentor could set high standards in a constructive and supportive way. However, he was much more than just an impressive scientist and mentor. He was a delightful person to discuss nearly any issue with. He always had strong opinions but he also listened with interest to the thoughts of others. Ken was a fine person and a great colleague. I will miss him very much indeed.

Gregory Ball Department of Psychological and Brain Sciences Johns Hopkins University

I first encountered Ken at a couple of conferences at which he gave talks. I admired his charisma and command of the material, as well as the respect he commanded in the audience. Throughout graduate school, I would find, somewhere down the line, that he had collected the relevant data and carried out, with customary elegance, just the right analyses for the project I happened to be working on. He was the only person I considered working with coming out of graduate school and was ecstatic that he would have me. Working with him was a thrill and an amazing learning experience. He was not just a great scholar, who jumped with ease from mathematics to biology then back again, but also a great man: generous, patient, personable and cultured. I consider myself very fortunate to have spent the little time I was granted with him.

Sliman Bensmia Postdoctoral fellow, Neuroscience Johnson Lab, JHU

Ken and I were neighbors, friends and colleagues for the first two years of my tenure at Hopkins (1970-1972). Merle and I still live in the Mount Washington home we bought at the time, and I still think of Ken when I drive around the corner and past the Crest Road house where he had lived. That house and Ken and his family hold a special place in my memory because it was there that I had dinner on November 13, 1971, the night of the birth of our first child Ben. I also often think of Ken in the house because of the shock he must have had when he returned from Australia and discovered that the price had risen by an order of magnitude in the ten years of his absence! Our friendship was really forged over the course of two years of commuting weekly from Baltimore to the Applied Physics Laboratory. We were both early risers so that a typical APL day began about 6:00 A.M. and didn’t end until after 10:00 P.M. We along with Larry Schramm had been assigned to develop and teach a course in what was then called the “Evening College” at APL. That course was to become what is now regarded by many as the hardest undergraduate course at Hopkins – Physiological Foundations for Biomedical Engineering. It was a real education for me, coming as I did from MIT in Electrical Engineering where my physiological education consisted of little more than a couple of graduate seminars. What a pleasure it was to listen to Ken, who had learned his physiology in the medical school and in the laboratory of Vernon Mountcastle, and Larry whose PhD was in physiology, lecture about material they knew as well as anyone. It must have required great patience on their part to listen to me lecture on respiration as I tried to keep at least an hour ahead of the students! It was very disappointing to learn that Ken was following Ian Darian Smith to Australia, but even more exciting after ten years to hear from Vernon that he was returning. For more than twenty years Ken played a major role in Biomedical Engineering at Hopkins. Although his primary appointment was in Neuroscience, Ken never lost his strong ties with BME. He was a biomedical engineer to the core and was an eloquent spokesperson for the biomedical engineering/systems approach to studying the brain. He is deeply missed not only here at Hopkins but throughout the world of neuroscience. Merle and I send our most sincere condolences to Jennifer, Lissa, Marin and Ben.

Murray B. Sachs Johns Hopkins University

I am greatly sadden to hear of Ken Johnson's passing. He is a tremendous scientist and friend and he will be greatly missed. I first met Ken when I was a postdoc with Vernon Mountcastle at Johns Hopkins. Ken and his wife Jennifer arrived at Hopkins a year after I did. In the two years that we overlapped I learned a great deal from Ken. His knowledge and understanding of the field was truly phenomenal. On the personal side, he was a warm and caring individual who took a keen interest and nurtured all those around him. It was no surprise to me that in the subsequent years Ken rose to prominence as a leader in the community at Johns Hopkins as well as the world wide community of Neuroscientists and Bioengineers. My wife, Carol, and I wish to send our deepest condolences to Jennifer, Ken's family, Ken's mentor Vernon Mountcastle, and to Ken's colleagues at Johns Hopkins and other institutions.

Richard Andersen Caltech

I was the first graduate student to join Ken's lab after his return to Hopkins in the early 80's. I remember with great fondness our early efforts to cobble together a working electrophysiology lab from a diverse collection of hand-me-down instrumentation begged, borrowed and built. I knew that the experience of getting a lab up and running from scratch might serve me well later in my career, and Ken was a terrific and patient mentor. As it turned out, I ended up applying Ken's lessons in a different context when Mark Longerbeam (also of the Bard Laboratories) and I started a biomedical engineering consulting business. Ken's love of science, and his insistence that I always do the highest quality research I was capable of have stayed with me throughout my career. Though I left neurophysiology after finishing my PhD with Ken, his views on science, general problem solving, and teamwork have remained with me. Even his views on music have stuck with me. I was looking forward to seeing Ken this spring to tell him that after all his urging and all my small-mindedness, I have finally developed a real love of Zydeco. I'm sorry that I never got the chance to tell him in person, but glad that I'm carrying a few pieces of him around with me. I've even had the chance to pass them along to my students, colleagues and now, my children.

Ken Fasman, PhD in Biomedical Engineering Director of Drug Development Strategy & Performance, AstraZeneca

Even though my lab was on a different campus to his, and I had no particular affiliation with him, other than being a PhD student in a department in which he held a secondary appointment, Ken was a wonderful, wonderful mentor to me. His encouragement was especially important to me when I struggled through the early part of med-school. He was kind, insightful, and generous with his time. And I always left a meeting with him thinking that I had learned something. I remember attending a weekly systems neuroscience journal club with him, and often marveling not only at the striking acuity of his insights but at the clarity and modesty with which he explained them. I looked forward to these journal club meetings more than any other event in my grad-school career. Ken also gave me great deal of support and encouragement last year when I decided to seek a faculty position. I will always be truly grateful for all his help and encouragement. I was lucky to know him.

Maurice Smith MD, PHD in Biomedical Engineering from JHU in 2003 Assistant Professor, Harvard University

I did not know Ken well on a personal level. However as an editor I constantly relied on him to review papers about somatosensory physiology and function. The quality of Ken's reviews were extraordinary and his scholarship was astonishing. Ken was an especially gentle reviewer. His advice to authors was always clear, calmly stated and insightful. Any author who received feedback from Ken greatly benefitted from the experience.

Dr. Peter L. Strick VA Senior Research Career Scientist Pittsburgh Veterans Affairs Medical Center and Co-Director, Center for the Neural Basis of Cognition Professor, Department of Neurobiology University of Pittsburgh

Although we know that Ken would not feel comfortable with being adorned with words of praise, I would simply like to share how Ken has been such a meaningful part of my life. Nearly twenty years ago KOJ provided me with the opportunity to work for, and learn from him at the Bard Laboratories. Since that time, he has been a mentor and friend in the truest and fullest senses of the words. He cared about both the career and personal well-being of each of his disciples. He has been a role-model in careful and thoughtful work. The brilliance and care of his work spoke for itself and lacked any pomposity. He also has been a role-model in striving for fairness and justice. He recognized, nurtured, and encouraged the gifts of others regardless of “pedigree”, he himself coming from humble origins of rural Washington State. He never ceased to appreciate the wonders of life and he fought courageously for life. May we be comforted by having been blessed by his friendship and having the fond memories of him imbued in us forever. Sharon, Lauren, and I send our deepest condolences to Jennifer, Marin, Lissa, Ben and Maria.

Robert Van Boven

I was Ken’s graduate student in the 1980s, and I’ve been his colleague at the Mind/Brain Institute since 1996 The first thing that comes to mind about Ken is how incredibly smart he was. Ken had no trace of intellectual vanity, he never tried to impress others with his intellectual capacity, but I’m sure that many who knew him well, including me, would say he was the smartest person they had ever met. He was unreservedly generous with the creative ideas that tumbled forth from his mind, to the great benefit of his scientific colleagues and students. As a result, much of the current thinking about how the brain works, especially about how populations of neurons encode information, owes a largely unacknowledged debt to Ken. Ken’s brilliance, boundless enthusiasm and energy, and plain-spoken eloquence made him an inspiring and visionary spokesman for the excitement and potential of brain research in the coming decades. Ken could motivate any audience with his compelling description of how the eventual discovery of information coding principles in the brain would be as revolutionary as the discovery of DNA triplet coding. That visionary touch also made Ken a charismatic mentor who deeply influenced his students’ careers. He defined the goals and approaches that have been and will remain the guiding principles of my research, and I know that’s true for many others. Since Ken was my mentor for 20 years, and I regarded him so highly as a thinker and a person, he was typically the first colleague I would try to find to get advice about career problems or to share any good news about data, grants, or publications. That’s how I have most noticed his absence in recent months; there have been many things I wanted to talk to Ken about and no longer can.

Ed Connor Mind/Brain Institute and Department of Neuroscience Johns Hopkins University

I followed Ken's work from his first publications on the difference limen in cutaneous thermosensation, quantitatively comparing neuronal and behavioral performance and identifying a remarkably low redundancy of neural population transmission in trained subjects. Later, his analysis of tactile spatial resolution transmitted in a population of cutaneous mechanoreceptive afferent fibers became the cutting edge in psychophysiology research on the brain/mind interface. The German Textbook of Medical Physiology (Springer) contain these masterpieces of Kenneth O. Johnson, commemorating a dedicated scientist to German students and teachers. I remember a few personal meetings with Ken between 1970 and 1980 in the US and Melbourne, and was deeply impressed by his ingenious concepts and experimental verifications.

Manfred Zimmermann Professor of Physiology University of Heidelberg, Germany

I was a graduate student with Ken at Johns Hopkins from 1992 to 1998. I am currently an Asst. Prof. at MIT, due, in no small part, to Ken’s help and support all along. In setting up my lab, thinking about science, and interacting with people, Ken has been, and will always be, my best role model. Here are some of the words and phrases I use to remember him: Optimism Clarity of thought Idealism Compassion Integrity Long lunches Rigor Defender of those that cannot defend themselves Systematic Understanding It is easy to tell many stories about Ken’s keen scientific insight, his friendly, open nature, and his willingness to spend endless hours helping others. Instead, I would like to try to convey a more personal story that no one but Ken has heard and that meant a great to deal to me. I was a young graduate student, preparing to give my first talk on work I was doing with Ken at a national scientific meeting – the Society for Neuroscience meeting. I had just spent the last several weeks and late nights intensely analyzing the data I had collected. Like many young graduate students, I had been pouring all my efforts into the analyses and figures and had little time left over to practice my presentation. Nevertheless, I proceeded with a practice talk in front of several Hopkins colleagues with less than 48 hours until the meeting. I was fully sleep deprived and highly on edge. Needless to say, the words were not ready and I stumbled badly through the presentation. After everyone had left the room, it was left to Ken and me to digest the situation. In discussing how to improve things, I suddenly began to feel overwhelmed with disappointment in myself. At that moment, I could not say if I was more embarrassed by my incomplete scientific progress to date, my poorly executed practice presentation, or that I suddenly did not seem able to hide my emotions from my scientific mentor. This is perhaps the most uncomfortable situation one can put a typical rational, rigorous scientist in. Yet Ken responded with astounding understanding and compassion. Somehow Ken instinctively new, that a hand on my shoulder, a reminder that this was good work, and renewed, rather than weakened, confidence in my abilities were exactly what I needed. After a good night’s sleep and a bit of practice, everything worked out wonderfully at the meeting. To this day, I still have tremendous respect, appreciation, and thanks for Ken’s deep compassion as mentor. ---- In closing, I would like to say that Ken still impacts my life nearly every day. As we are just now publishing papers on work generated in my lab, I still cannot help but think: “How would Ken make this study better?” “How would Ken say this more clearly and succinctly?” “Is there a deeper way of looking at these data that Ken would see?” Most importantly, “Would Ken be proud of this?” It is this last question: “Would he be proud of this?” -- or perhaps better said, “Would he be proud of me?” -- that reminds me that I see Ken as a genuine scientific father. Indeed, the last advice he gave me was that “children are great” – “have children!” Ken was, is, and will always be, my scientific father and a beacon of light to me. It is a great honor and privilege for me to have spent so much time in his bright light. And I think all of us here today still bask in Ken’s light, now sparked and carried within each of us that knew him. I know that Ken wants us to carry that light forward to our own students and children and, to borrow Ken’s words, “I will do my very best."

Jim DiCarlo MD, PhD Johns Hopkins 1990-1998

I would like to offer some comments about Ken and his psychophysical work and its impact. I first met Ken at a meeting in November of 1981 in Philadelphia. The meeting was the Tactile Research Group which was started by my advisor Frank Geldard. Ken talked what has become an often-cited, seminal study in the processing of spatial patterns by the somatosensory system, the results from his collaboration with John Phillips. The Tactile Research Group was made up of experimental psychologists, nearly all of whom would characterize themselves as psychophysicists. Ken spoke in his usual low-key, modest fashion describing the multiple measures of spatial acuity, grating orientation, gap detection, letter recognition, any one of these would have been a separate publication for someone else, and then he showed the spatial event plots of the responses of RA, SA, and PC afferents. Ken finished. No one said anything for a moment and then Frank said, and this was first and only time in the 20 years of these meetings that I ever heard him say this, he said, “I don’t know about the rest of you but I am going to applaud.” Ken and his work have had a profound influence on the field. To take one example: The standard measure of spatial acuity for 150 years has been the two-point threshold: How far apart do two points have to be before a person feels two points rather than a single point. There are numerous problems with this measure, foremost of which is the fact that the judgement of what feels like one versus two points is greatly affected by the subject’s criterion. A subject who adopts a conservative criterion and is less likely to respond “two” until the points are widely separated will appear to be relatively insensitive even if their underlying neural structures are perfectly normal. Ken’s developed and promoted the grating orientation task in which a grating in placed against the fingertip, for example, and subjects are asked to tell whether the grating is aligned along the finger or across the finger. It has replaced the two-point threshold as the standard measure of spatial acuity. This spring I was on a dissertation committee in the Department of Speech and Hearing at Indiana University. The student was investigating Parkinson’s patients to see if they showed sensory deficits that were correlated with their motor deficits, particular speech problems. Prior to Ken’s work, the two-point threshold would have been a likely measure, and we would have been unsure how to interpret any changes found. The student used the grating orientation task and found a loss spatial acuity relative to age-matched control subjects and greater loss during speech tasks. The speech difficulties seen in Parkinson’s patients may be due in part to a sensory-neural loss. The way that Ken demonstrated that grating orientation is a valid measure of spatial acuity is typical of his approach to answering scientific questions and is a model for scientific inquiry. Ken was a firm believer in Karl Popper’s approach to scientific theory, proving a theory by trying to falsify it. Each of the measures of spatial acuity that Ken devised was designed to push the limits of his model of peripheral innervation. All of the measures turned out to be highly correlated with one another and, and this is another hallmark of Ken’s work, the measures could be shown to be quantitatively related as well. When describing a particular project, Ken might say that this is “textbook material,” meaning that the work is so fundamental that it will appear in standard textbooks. In terms of his influence on psychology, it should come as no surprise that Ken’s work on the psychophysical and neural basis of spatial acuity and tactile pattern processing is already in the standard textbooks in sensory psychology. More recently his studies on roughness perception are clearly “textbook material” and will, I am confident, appear in the next publication cycle of those textbooks. Part of the reason that Ken has been such an influence in the field is personal. Ken has been willing to tackle the difficult problems and had the drive to stay with them and solve them. One of these difficult problems is the development of an adequate tactile stimulator. There have been a lot of people who have contributed to the development of the 400-probe array, and I see many of you here today. Ken, of course, was the driving force behind its development. I remember, vividly, an awkward moment some number of years ago. I was renewing my grant and in the renewal I discussed the progress on the development of the 400-probe array. The study section decided that they wanted to see what the progress was on the probe before voting on my grant. The site visit took place at the Applied Physics Laboratory. Ken could not have been more helpful including the moment when the tip on our only working motor snapped off as the site visitors watched. Ken said I turned whiter than the sheet of paper I was holding, but he simply said,”Oh that’s nothing” and proceeded to reattach the tip and get on with the demonstration. And the grant was funded. Those of you who have collaborated with Ken in writing a paper know about his use of brackets to enclose editorial comments not meant to be in the paper. In writing a paper together Ken and I found the queries and requests from the editor and copy editor to be pretty picky. At one point we agreed that dealing with them was like being pecked to death by ducks. From then on, I would receive a draft from Ken and sprinkled throughout the paper following some change requested by the editor would be Ken’s brackets with “Quack, quack” inside. Ken was a great person to talk to. He had tremendous enthusiasm about other people’s ideas. Anyone who talked with him knew that they had his full attention. I saw it over and over again in my conversations with him and in watching him talk with others, his ability to take someone’s idea and work with it and help shape it until the person finally stated it in a much better, clearer, testable fashion and then Ken would say, and, I think that this was one of his favorite expressions, “That’s terrific.” Ken was terrific.

James C. Craig Chancellor's Professor of Psychology Dept. of Psychology Indiana University

Memory of Ken Johnson My name is Takashi Yoshioka, and I had the privilege of working closely with Ken for the last 7 years overseeing the research operation in his lab. Ken was a brilliant scientist as many of you know. Ken also took his teaching responsibilities just as seriously as his research. He was generous with his time and very patient to explain concepts until his students and colleagues understood the material. He was a friend to anyone who came to him for guidance. He guided undergraduate students in BA/MS program in Neuroscience, and counseled graduate students who were looking for the right mentor, and discussed complex mathematical problems with his students and colleagues. Above all, he was a decent man who appreciated, respected, and enjoyed people. Ken wanted to make sure everyone in the lab felt that he or she was part of the team. He delighted in making people happy, practicing the Golden Rule, “Do unto others as you would have them do unto you.”, which he often quoted. When I joined his lab coming from the background in vision research, he helped me catch up in the field of somatosensory research by giving me the co-authorship of an article he and Steve Hsiao were writing. After a closed door meeting with Steve, Ken emerged with a big grin and told me to be a coauthor of the article. While waiting for my response with a big grin still on his face, he said, “Now, now, you need to make a substantial contribution to be an author, but don’t worry, I will help you.” Ken was brilliant, but he also worked very hard. It was not uncommon when Steve, Jim Craig and I exchanged emails with Ken over the weekends, and sometimes after midnight, sending back and forth computer files of manuscripts or grant applications. He was a hard worker, but he had a sense of balanced life. I recall one time when my work was not going well and faced one evening with the choice of whether I should celebrate my wedding anniversary with my wife or stay in the lab to complete my work. Ken said, “Don’t worry. We will figure that out. Take Julie out and enjoy your anniversary dinner.” He recommended a particular restaurant and said, “Make sure you make a reservation.” So, I made a reservation and we enjoyed the excellent dinner. When we were about to order dessert, the waiter said, “This is a courtesy from Mr. And Mrs. Johnson.” We were surprised to learn that he and his wife had arranged to pay for our dessert as an anniversary gift. We were very touched by his kindness and thoughtfulness. It was as if he was saying, “As important as our work is, having dessert with a loved one is equally important.” I miss Ken, my mentor and my friend.

Takashi Yoshioka, Ph.D Zanvyl Krieger Mind/Brain Institute

I am a graduate student in Ken's lab since 1999. I arrived in the lab, fascinated by the brain and my head in the clouds. Today, the fascination is the same, but my feet are on the ground. Ken had a profound impact on how I thought about problems. When I joined the lab, I was interested in phenomena like attention. I remember Ken's reaction to it. He said, "It goes up, it goes down", and he shrugged in his characteristic manner. I couldn't help but agree with him that the real challenge was to understand how information is represented and transformed in the brain. Ken always asked the best questions in any seminar or journal club. And afterwards, he would ask, "Did my question help? I thought people needed to understand..." Once, when we were all lost in the details of a paper, he asked, "So what does this really tell us about the brain?" And he was right! Ken would quickly get to the real issue, and judge the importance of a piece of work in the larger context. Over the years, I would read Ken's papers and marvel at their clarity, depth and insight. When we sat together to work on my papers, I saw how much effort he would put in to convey ideas clearly and concisely. Ken was really brilliant at theory, but he would only use it as a tool to understand what the data meant. I would often come to him, excited about using a technique – and find that he would agree to using it only if it was really useful. He was an excellent critic when it came down to discussing ideas, data or experiments. Today, as I prepare to leave the lab, I find myself a part of Ken's legacy, an aspirant to the qualities he exemplified: a high standard for publication, attention to every detail, modesty, equanimity and generosity. I hope to be a scientist of Ken's caliber. It's a tall order, but it will the best tribute to Ken. I hope I can live up to it.

Arun Sripati

Ken was my mentor, colleague and friend for the past 25 years. I never imagined when I decided that I would be a graduate student in his lab so many years ago that it was going to be a life long commitment. Ken was a great scientist and teacher. He was a clear thinker who had a unique way of simplifying problems be they scientific or social. I was thinking back and I estimate that we probably talked 4-5 times a week for 25 years and over that time we talked about practically everything. What I’d like to do today is to reminisce about the Johnson-lab lunch-time conversations, which I think many of us who worked in Ken’s lab will miss greatly. For those of you who weren’t there, lunch was a time where all the problems of the world were solved. Typically, they would start with the lab members going to the NE market in the olden days or more recently to Eddies and bringing back lunches to the workroom. Ken would then come out of his office with his can of salmon and bottle of diet coke and we would then proceed to solve whatever was the current issue of the day. For example, Was OJ guilty? – I think we all thought yes. Should Clinton resign? –Some of us thought no but Ken thought yes. No topic was left untouched. When I began in the lab, Ken, John Phillips, Ken Fasman Ed and I would have long arguments that would only be resolved by the American Heritage Dictionary, or by a passage from Fowlers being read. By the way it had to be the AHD and Fowlers. One day I brought out my Websters dictionary and was told that Websters didn’t count. To settle arguments that could not be solved using the dictionary, Ken would typically invoke statistical arguments using hypothetical data to support his positions. How can one argue against someone who uses bell curves and P-values? It was because of Ken and these lunch-time conversations that I started subscribing to Consumer reports and started reading the New York times religiously. Ken was a great believer in people and in the belief that we could live in a great society but only if we chose to do so. One of Ken’s favorite positions that often stirred up heated discussions was his belief that government is responsible for practically all of the great things in society? Often the conversations would turn to Ken’s favorite topics. He loved music but not all music. He loved the Stones, zydeco and the blues and hated the Beatles, who many of us liked. Whenever I hear the Beatles now, I can’t help but hear Ken making fun of “maxwells silver hammer going ding, ding, ding on his head”. Ken also loved movies. And like his taste in music, he loved movies with a bit of grit in them. Let me give you an example. One movie that Ken recommended was “Brothers Keeper” I don’t know if any of you have seen the documentary but it is about two illiterate, elderly brothers who sleep and live together in a two-room filthy shack in Pennsylvania. If you want to see a movie with grit this is it. By the way, after watching this movie with my wife Jocelyne, she asked me - “Was that another Ken movie”? From then on we have had an unwritten rule at home that I have to clear “Ken Movies” before I can rent them. But I guess that is over now. With Ken’s passing I have lost not only a mentor who has guided and molded me into a scientist but also a close friend and confidant who has played a major role in shaping my beliefs and how I approach life. I will miss him greatly.

Steven Hsiao

My name is MG. I didn't know Ken as a world-class research scientist; I knew him as a world-class human being. My wife Paddy and I are very fortunate to have had Ken and Jennifer as friends. It was always special getting together. Special because of its rarity as Ken worked so hard, and special in that we always had a wonderful time. The conversations were alive with heart-felt concerns, critiques and delightful moments, as when we disagreed with our wives regarding how long a red wine needed to breathe: Ken and I claimed that as soon as the cork was removed that was time enough; fortunately the bottle's contents never lasted long enough to reject our self-serving hypothesis. Yet as alive with good fun and meaningful as the conversations were, they were never about his life of work. It was the work of life he shared with us, of what was involved in living with care in all facets of one's experience. And this was deeply appreciated by us, and in Ken's warm and utterly unpretentious manner, inspiring. It could be found in his spirited attention to detail in making a really good cup of coffee; as well as in his delight in hearing an insight come to life yet without making the point that he deserved considerable credit for its creation; and in his indignation at those who rationalize a politics of exclusion -- the trickle-down version of divine right. Ken's deep commitment in science to advance humanity manifested in his private life in his deep concern for the underclass -- those of us who find ourselves in the least desired place in a society that promulgates pulling oneself up by one's bootstraps, even when there aren't any. Here his indefatigable passion for science done right would be transformed into the complete exasperation he felt in thinking about the insensitivity and arrogance of those who would act as if we weren't all in this together. His continuing support of Jennifer's work as she sought to capture in her research the voices and otherwise submerged experience of working-class women on the thinnest branch of the economic tree was a natural extension of Ken's deep humanitarian concern. Given the depth of his professional and personal dedication to his fellow human beings, it would indeed be fair to say it permeated his being and, as we have heard today, was rather unceasing. Yet, we all know there comes that time, for death is the cost of the ticket for the ride. So it was Ken's aspiration that life could be well-lived by each of us, for then it would be a just price. He wanted that all of us 2-legged creatures scuttling around at the bottom of the ocean of air on this extraordinary slip of organic life in an apparently barren neighborhood in the universe would be responsible to each other, would treat each other with kindness and compassion, would be decent. His was a beautiful spirit that we will sorely miss; the loss of his life-affirming energy and exceptional mindfulness leaves the world a lesser place, indeed flatter. So I take comfort in the belief that those of us who can draw upon the integrity he brought to his leadership and his research and those of us who were enlivened by the light of his conversation and compassion cannot but be affected for the better; we are indeed more than we would otherwise have been. Paddy and I miss Ken and the chance to sit around and laugh and carry on about what is right and just. Indeed, we will miss him greatly.

Marshall Gordon