I have been a neuroscientist for nearly 50 years. I have dedicated my life’s work to unraveling the mysteries of the human brain, the ultimate frontier in science.
Research into the function of the brain can not only help us understand how it works, but can inform our understanding of what goes awry in brain disease and how we can treat it.
The joys and rewards of this labor are many. Our research has become the basis for a new clinical treatment for tremor. Our work has informed the design of experimental therapies for neurodegenerative diseases such as Alzheimer’s, as well as for the deadly brain cancer glioblastoma, the disease that killed my mother.
Knowing that my research may help treat people with conditions that kill them swiftly (such as glioblastoma) or diseases that slowly rob them of memory, personality, joy and, eventually, life is what propels me to go into my lab every day.
Despite the many joys of my work, it has at times, been misunderstood. Over the last several days, I have joined the ranks of scientists targeted and demonized by opponents of animal research, who seek to abolish lifesaving research in all animals. In doing so they threaten to thwart medical progress for the benefit of all people and, indirectly, for other animals.
Their tactics have miscast my work, twisted facts, and spread inaccurate and false information wrapped in emotionally charged, inflammatory language. This rhetoric has spurred aggressive and threatening messages, and I have become increasingly fearful for my safety and for the safety of my family.
I will attempt to dispel some of the pernicious myths about my research and set the record straight. I owe this explanation to the general public, to medical science, to my colleagues who are treating patients at their bedside, to my peers who study basic mechanisms of disease at the lab bench, and, most of all, I owe it to all the people and other animals who stand to benefit — in the near or distant future — from research conducted in animals.
Though I have been a neurobiologist for more than four decades and worked with rhesus monkeys throughout the years, I only started working with young macaques in 2014. While non-human primates make up a tiny portion of animals used in biomedical research, they are invaluable in studies that require animals with a visual system, brain, immune system, and certain disease susceptibility similar to those of humans.
In 2016, we performed two reversible eyelid-closure procedures in macaques using dissolvable sutures, as described in the peer-reviewed literature. This procedure is also performed in human children and infants with certain eye tumors or to treat invasive eye infections. Pediatric surgeons give these children anesthesia and pain-relief medications. We did the same with our infant macaques to ensure they do not experience pain.
The two cases we performed in 2016 built on research performed in the 1960s by HMS Nobel Prize winners Hubel and Wiesel who mapped the organization of the human visual system — research that has been described as a quantum leap in our understanding of how the brain “sees.” Hubel and Wiesel’s studies changed the treatment of congenital cataracts, strabismus (misaligned eyes) and lazy eye, or amblyopia and, over the years, have helped save millions of children from vision loss.
Building on Hubel and Wiesel’s early transformative work, we wanted to probe further how the brain works. To do so, we used non-invasive brain MRI—a technique that was not available at the time of the original studies. Using brain MRI allowed us to go beyond these original observations and see in full detail the effects of temporary vision deprivation on the entire brain rather than just on parts of it, with a level of precision that Hubel and Wiesel could not foresee.
We have not performed eyelid closures since the two isolated cases in 2016 and have no plans to do so again. However, the two 2016 cases have been studied and reported in subsequent papers because they yielded many insights. My lab now uses entirely non-invasive techniques to study early visual experiences. These include caregivers wearing facial masks and having the animals wear goggles. Notably, eyelid closure was and remains routine protocol across research labs that study vision disorders. This technique, in fact, paved the way for the modern non-invasive methods we use now.
Although we do NOT pursue maternal attachment as a line of research, our lab made observations on maternal bonding and attachment in the course of other research. It started when one of our macaques delivered a stillborn. In an attempt to comfort the distressed mother, we gave her a stuffed toy. She relaxed and adopted the toy as her baby. We subsequently provided other macaque moms with Beanie Babies and soft-cloth toys. We now use this comforting measure for newborn macaques abandoned by their mothers and on the occasions when they are separated from them. These newborns were calm and held on to their soft toys. In fact, they are behaviorally indistinguishable from infants reared by their mothers. Other researchers working with monkeys, as well as primatologists, should benefit from this knowledge and use this as a calming measure in their own work.
But people might ask how this work helps humans. Beyond showing that maternal attachment could be triggered by soft touch, these observations can inform the development of comforting interventions to help women cope with loss in the immediate aftermath of a miscarriage or still birth.
Our research on face recognition has illuminated how deficits in some brain regions can lead to face blindness and to certain social difficulties in children with autism spectrum disorders. Our work demonstrates that our brains get wired up according to what we experience in early childhood during critical windows. This insight is important for how we deal with children who have experienced deprivation early in life. This can also help inform education measures for such children. Finally, our work points to possible interventions for children with autism who might choose not to look at other people or their faces.
Our work with adult macaques focuses on how the brain processes visual information at a higher level. We use standard techniques common across nonhuman primate labs that involve the implantation of electrodes similar to those used in patients with epilepsy or for deep-brain stimulation in people with Parkinson’s disease. Indeed, these brain–machine interfaces that now benefit so many with neurologic disorders were developed through research in nonhuman primates. We use this same approach to see how adult macaques process visual information they see on-screen.
Our other research in adult macaques involves the blood-brain barrier, a complex network of blood vessels that protects the brain from toxins and pathogens. Yet, this protective barrier also hinders the delivery of medicines into the brain, posing a daunting therapeutic challenge. To circumvent this hurdle, we use focused ultrasound waves to nonsurgically inactivate, or ablate, certain brain regions and to temporarily “open” the blood-brain barrier. This temporary permeability of the barrier can allow the delivery of targeted therapies into the brain and transform the treatment of brain cancer and neurodegenerative diseases.
Some of this work has already led to clinical treatments. Our technique is now being investigated in clinical trials as a way to deliver chemotherapy directly into the brain for the treatment of glioblastoma and for breast cancer that has spread to the brain. The approach has also shown enough promise to be used in clinical trials to treat Alzheimer’s disease. None of this would have been possible without our studies in macaques.
The implications of our work for human health are important, but so are the contributions to our broader understanding of the brain’s most sophisticated and highly evolved aspects of visual processing, especially those related to object recognition, such as faces, bodies, and scenes. This knowledge forms the foundation for future generations of neurobiologists and is already a part of neurology and psychology textbooks.
All of the research procedures we use are done in a manner that aims to provide comfort, minimize distress, and reduce or completely eliminate pain.
All of my research is subject to extensive federal, state, and institutional policies, regulations, and oversight groups charged with ensuring the proper care and treatment of research animals and ensuring that the use of animals is justified and cannot be achieved through alternative means. Beyond our natural instinct to care for our animals, the humane treatment of animals is also critical to our ability to conduct our research in the first place: Animals that experience distress, pain, or discomfort cannot be studied and our results would not be valid.
All of my work is reviewed by peer scientists and funded by the federal government. For more than three decades, this work has garnered sustained support from the National Institutes of Health, which underscores the value and promise of this research for our understanding of the human brain in health and disease.
Our work has direct and indirect implications for human health, whether it leads to therapies for vision disorders, treatments for neurologic diseases and cancer, or helps alleviate the sense of loss experienced by women who suffer miscarriage.
Do I wish we lived in a world where generating this important knowledge were possible without the use of lab animals? Of course! Alas, we are not there yet. We continue to work toward this future through our ongoing efforts to refine, reduce, and replace animal models — the three Rs of animal research.
I realize that working with animals is a privilege that requires vigilance and responsibility. To honor that, we take great care of our animals beyond what’s mandated by even the most stringent federal regulations. We provide a nurturing environment, and I am proud to be an integral part of the animal care team. For example, as a morning person, I do all the early-morning bottle feedings of our baby macaques.
If you or a loved one has ever had a vaccine, taken a pill for high blood pressure, or been treated for diabetes, cancer, infection, or heart disease, you have benefited from animal research.
Whether you support animal research or not, you have benefited from therapies derived from work done in animals. And so have your pets. Veterinary medicine also relies on studies in animals. Pets that receive antibiotics, pain killers, cancer treatments, or vaccines or have surgery are the beneficiaries of research done in animals.
I love the animals I work with, and I am forever grateful for their vast contributions to medicine and science. We all should be.
Marge Livingstone is the Takeda Professor of Neurobiology at Harvard Medical School.
See Harvard Medical School’s institutional statement on this matter here.