When asked to specify the contributions of animal research, almost
always we tend to think about its immediate therapeutic benefits. Whether
proponents or adversaries of the use of animals in research, we focus on
medical procedures, on new drugs and on their testing. Of course, this is
important but, in my opinion, the crucial contribution of animal research is
not in this direction. It has been and still is in providing the foundation of
our understanding of human body functions.
Basic research essentially means animal research.
When I was teaching Basic Neurology to first-year medical students, in anticipation of the week of “animal liberation” (sometimes in April), I used to tell the class: “Look, if we had to delete from this course all the material based on discoveries made first in experiments on animals, the course would be terminated in three weeks.”
Let us see if it is true. A course on the nervous system usually starts with cellular (neuronal) mechanisms. What we know of the nerve action potential has been learned by experiments on invertebrates (e.g., squid). Synaptic transmission has also been most intensively studied in invertebrates (e.g., aplysia), and later in cat (e.g., by Eccles). The role (including the distribution maps) of synaptic transmitters has been established in cat. Reflexes, their supra-spinal control, and the effect of spinal transection, for instance on walking, were elucidated in cat. So are the detailed tracing of sensory and motor pathways, using for instance horseradish peroxidase, and the reconstruction of local circuitry (e.g., in cerebellar and cerebral cortex). What we know of neuro-endocrinology mainly derives from observations made in rats, mice, rabbits and cats. So is our understanding of sleep, respiratory and cardio-vascular controls, and stabilizing interactions within basal ganglia and associated structures. Animal research has also provided most of the cellular observations to explain the development of epilepsy or extra-pyramidal disorders. Today, implants are tested in monkeys to re-establish connections between the brain and muscles in order to fight paralysis. When I started teaching Basic Neurology, very little was known of the significance of non-sensory and non-motor cortical areas. Collectively, there were known as “association areas” (which was a way to express our ignorance). Today the significance of these areas is much better established thanks to microelectrode recordings in behaving monkeys and thanks to MRIs in humans. But, practically, the rapid progresses made by MRI exploration have only been possible because they have been anticipated and thereby prepared by the microelectrode work on monkeys. Exceptions are rare; they are the cases (e.g., problems of human language) where work on monkeys cannot help very much and, therefore, progress is slower.
I am sure that our colleagues will amend, amplify many of the points
made above and add other points. This list is not limitative. Yet it is already
too long to serve as an answer to the question: “What should we respond to the
criticisms hurled by animal activists”? So let me also propose a short answer: Almost all we presently know about the brain
finds its origin in animal research.
John Schlag, MD