I draw every day. When I travel, I often make multiple drawings in a single day as a way of metabolizing experience. Drawing is how I slow time, how I study what I am seeing, and how I translate movement, place, and conversation into something structured and deliberate.
My Cajal project extends beyond reproducing his scientific illustrations. It also encompasses his laboratory equipment, personal photography, personal objects, and the cities and buildings that shaped his life. The project has taken me across the United States and Spain, to archives, museums, universities, and research institutions, where I draw not only in response to Cajal’s legacy but in response to my own presence in those spaces. Parallel to my research drawings, I have created a second record: a visual diary of travel, observation, and encounter, where each page becomes a quiet negotiation between past and present.
During the Cajal Club Social at the Society for Neuroscience meeting in San Diego this past year, I drew Pasko Rakic as we sat together, waiting for the festivities to begin. We are both club members and part of the board of directors. Pasko has been a member of club longer than any of the current members, and he was invited to become a member by the Cajal Club founder Wendell Krieg. We visited while I sketched and he shared with me his interest in art during his youth. I wanted to complete the portrait while we sat together and not just begin a drawing that would be completed at a later time. So fingers flying with a sense of urgency and audiating "Flight of the Bumble Bee" in my head, I completed the portrait within a half hour. While I drew, Pasko was both pleased and intrigued by the speed and competency of my drawing ability. He was reflective and humorous while we talked, sharing experiences from his childhood and career. I was struck not only by the arc of his scientific career, but by how his early interests in neuroscience was shape through his exposure to Santiago Ramón y Cajal’s drawings.
Pasko Rakic was born in Ruma, 1933, in what was then Yugoslavia; a country that no longer exists. His childhood unfolded against the violence and instability of World War II, in a multi-ethnic region shaped by shifting borders and ideological upheaval. Like Cajal, whose youth was marked by political turbulence in Spain, Rakic grew up in a landscape where identity was fragile and authority often oppressive. He witnessed death in the streets, the disappearance of neighbors, and the loss of family members to war. Books became refuge and resistance.
His mother’s eclectic library consisting of French and Russian literature, and books by Freud and Adler, offered intellectual sanctuary in the midst of chaos. Rakic read above his level, absorbed encyclopedias, memorized chess strategies, painted watercolors, constructed mechanical models from scarce materials. The pattern is strikingly Cajal-esque: the self-educated boy, fascinated by complexity, restless in conventional structures, drawn equally to art and science.
Both men initially leaned toward artistic expression. Rakic considered careers in art or architecture before being persuaded toward medicine by his father’s pragmatic wisdom: knowledge cannot be expropriated. Cajal, too, resisted his father’s push toward medicine, preferring drawing and literature before ultimately finding a way to fuse the two. For both, art did not disappear, it became a structural foundation of their research. Rakic drew cartoons and caricatures for newspapers while attending in medical school. Cajal transformed histological observations into visual poetry for his doctorate thesis.
There is another parallel: intellectual dissent. As a teenager, Rakic debated theology and questioned dogma, disturbed by the persecution of Giordano Bruno and Galileo. By fourteen, he had resolved to side with scientific evidence when belief and fact diverged. Cajal similarly challenged prevailing scientific orthodoxies, opposing the dominant reticular theory and advocating for the neuron doctrine despite resistance. Both men cultivated a habit of arguing against established authority, a trait Rakic admits sometimes worked to his detriment.
Perhaps most moving is Rakic’s own account of encountering Cajal’s drawings during a histology course in Belgrade. He describes them as opening “a universe of unbelievable complexity and beauty.” It was not only the problem of neuropsychiatric disease that drew him to the central nervous system, it was the aesthetic revelation of black silhouettes of nerve cells, and the imaginative leap required to understand their evolution and function. In that moment, Rakic became part of Cajal’s intellectual lineage.
Scientific illustration by Pasko Rakic, Specification of Cerebral Cortex Areas, ink on paper
When I drew Rakic at SfN, I found myself thinking about that chain of transmission, from Cajal’s wryly black neurons to Rakic’s cortex. My drawing became less a portrait of a man and more a study in scientific lineage and historical interconnection: skepticism, artistic impulse, devotion to complexity, and the enduring belief that the nervous system can be understood through disciplined observation and imaginative thought.
Pasko Rakic went to medical school and then entered internship and residency in neurosurgery. He then came to Harvard and received a Clinical and Research Fellowship in the Department of Neurosurgery at Harvard Medical School, chaired by William Sweet. He was assigned to work in neuropathology and soon ran into Paul Yakovlev, one of the leading neurologists of the time, who had worked with Ivan Pavlov before moving to Paris during the Russian Revolution. Yakovlev had a profound influence on Rakic’s thinking about the brain. Rakic said: “He also instilled in me the idea that understanding of the human brain will not come from the discovery of a single signaling molecule that we share with other creatures, but from unraveling the neuronal circuitry that underlies our mental capacity. He also believed, like Einstein, that the meaning of a finding is as important as the finding itself.” The fellowship was originally for two years but it took Rakic four years to learn all he wanted to learn about the developing human brain.
He came back to Belgrade and decided to give up practice of neurosurgery to become a Ph.D. candidate in developmental biology and genetics. The reason: he strongly believed that the fundamental science contributed more to medicine than the ordinary clinical practice at the time when almost all neurological problems were unproportional to the available clinical interventions. In his graduate work, he grew post-mortem human embryonic brain in culture, using tritiated thymidine (H3-thymidine) for labeling of the dividing cells. He was one of the pioneers in the field of research on neural stem cells using the slice culture technique, for the demonstration of neural stem cells, which had supravitally continuing to divide. His research revealed that the neurons in the human cerebral cortex were not produced locally but were produced in the proliferative areas near the cerebral ventricles, and therefore were migratory neurons that travelled to distant cortical fields. He described and demonstrated two transient proliferation layers namely ventricular layer and subventricular layer. Based on these findings, he was awarded an Assistant Professor of Neuropathology at Harvard Medical School in 1969.
Pasko Rakic lecturing by drawing the concepts or equations, Yale University
From the beginning, as a young scientist in the United States, Rakic experienced a competitive enterprise in which scientists are given intellectual freedom. Arriving at Harvard Medical School at an exciting period in the history of neuroscience when new advances in genetics, molecular and cell biology, electron microscopy, and immunohistochemistry were making it feasible to pursue a new generation of studies of the brain, Rakic began his investigations building upon his initial discoveries and focused on the kinetics of neuronal replication and the cellular mechanisms of neuronal migration. Intrigued with the temporal order in which different types of neurons are produced, developed, sequenced, and migrated to specific locations at great distances from their sites of production, Rakic carried out studies that clarified both the universal and the species-specific aspects of this phenomenon by studying developmental processes concurrently in several species: the mouse, the macaque monkey, and man.
Rakic celebrated the conclusion of a major NIH grant awarded in 1975, in which he studied monkey behavior brain development in primates by detailed autoradiographic techniques. He showed how monkey neurons are born and what the sequence in time of their birth and what their migratory pathway in the developing brain are. By comparing the time of their birth with the time of their birth and subsequent migratory pathway Rakic was able to show that the birth of cortical neurons in monkeys commences and terminates prenatally and at times comparable to those for man. Using techniques of autoradiography, a technique he pioneered, Rakic demonstrated how the new neurons migrate to their subsequent cortex location by traveling down what is known as the radial glial guide-rails that stretch right through the thickness of the developing fetal brain. These studies have led to the development of the radial unit hypothesis for brain development and then the protomap hypothesis for how the highly differentiated three-dimensional structure of the cerebral cortex develops from the one-dimensional plane of stem cells that reside in the germinal layers of the developing cortex.
Rakic is a major contributor to the understanding of neural plasticity. One of his key findings came from examining the visual projections in the developing primate embryo. Initially, these projections are jumbled up, but over time they sort out into the individual layers of the eye’s specific region of the brain. As the layers form, a large excess of connections between neurons is established, and these are later pruned out in a process that Rakic named “synaptic pruning.” Rakic’s work therefore supported the selective elimination hypothesis of development, which proposes that it is competition combined with environmental experience that provides the stimuli necessary to mold the structure of the developing brain. Rakic has shown that the development of the brain is a dynamic, competitive and evolutionarily highly refined process that deviates far from the classic image of a static architectural process.
Undated photo, Patricia Goldman-Rakic and Pasko Pasko Rakic, SfN annual meeting
Pasko Rakic was appointed to the Dorys McConnell Duberg Professor of Neuroscience at the Yale School of Medicine by Nobel laureate George E. Palade in 1979 and became the founding chair of the Section of Neuroanatomy. His future wife, Patricia Goldman-Rakic, arrived from the National Institute of Mental Health as an accomplished and highly respected neuroscientist. Their relationship was intellectually dynamic, marked by mutual support and candid scientific exchange. They co-founded the journal Cerebral Cortex; and played a major role in the development of the multidisciplinary approach of the Society for Neuroscience which both also served as presidents. They played a major role in the growth of the Yale Section of Neuroanatomy into the Department of Neurobiology that now houses the Kavli Institute of Neuroscience.
Upon his move to Yale, Rakic’s research focused on the molecular and cellular processes of neural growth and development. Rakic argued that cortical development was a highly heterogeneous process requiring interaction of a large number of genes, membrane proteins, ion channels and other structural components of the cytoskeleton. His lab has identified over twenty molecules regulating different aspects of stem cell proliferation, establishment of polarity, and migration to their final position in the developing cortex. In addition, the Rakic lab discovered that precise control of the speed and trajectory of the migrating neurons is critical for normal spatial positioning of new neurons. Alterations in the speed and trajectory of migrating neurons can lead to small abnormalities in the positioning of new neurons that are not detectable by detailed examination of postmortem brains. Such abnormalities are implicated in the pathology of various neurological and psychiatric disease including epilepsy, autism, dyslexia and mental retardation. Another important area of research in his lab is the adult primate brain. Rakic had long argued based on his studies of the very slow replacement of neurons in the postnatal primate cerebral cortex that evolutionary stability of neurons in the mature brain may be required for long-term memory at the expense of the regenerative capacity of the brain. This idea was met with strong counterarguments. Later however several independent lines of evidence supported Rakic’s hypothesis including carbon-14 birth dating studies in humans. In light of this knowledge, the field of stem cell research has shifted from being primarily focused on replacement to being also focused on preservation of the brains regenerative capacity.
Prior to receiving the inaugural Kavli Prize in Neuroscience, Pasko Rakic was honored with numerous major distinctions, including the Gerard Prize from the Society for Neuroscience, the Lashley Award from the American Philosophical Society, and awards from Bristol-Myers Squibb, the Pasarow Foundation, the Marta Philipson Foundation, the Henry Gray Award, the Weinstein-Goldenson Award, the Krieg Award, and the Fyssen Foundation.
He also served as President of the Society for Neuroscience and was elected to several distinguished academies, among them the National Academy of Sciences, the American Academy of Arts and Sciences, the National Academy of Medicine, as well as the Croatian Academy of Sciences and Arts, the Serbian Academy of Sciences and Arts, and the Norwegian Academy of Science and Letters.
Sandra Biller and Pasko Rakic at the 2008 reception for the Kavli Prize in Oslo (Norway)
For more than 40 years, Rakic’s research was recognized world-wide, generating tens of thousands of citations and scores of major awards. He mentored more than 50 graduate students and postdoctoral researchers; always valuing debate and arguments in science and helping them to establish new departments and laboratories. His personal life has been a rich combination of great partnership and great loss: he lived with his partner Patricia Goldman-Rakic for over 25 years until her premature death, and married Sandra Biller with whom he now shares a great passion for the arts. He has always been interested in both the science of the brain and in the other aspects of human life such as politics, mentoring, and the fundamental questions that initially motivated his interest for the study of the brain.
It has been a privilege to serve beside him on the Cajal Club’s Board of Directors, and I will long cherish the moment of drawing his portrait while listening to him speak about the arc of his life and research.
