This episode was made in partnership with The Kavli Prize, which honors scientists for breakthroughs in astrophysics, nanoscience, and neuroscience – transforming our understanding of the big, the small, and the complex. In the early 1970s, computers were suddenly everywhere, and neuroscientists saw something that appeared familiar: the wiring of the human nervous system. Scientists came to think of the brain that way, and of behaviors as being “hardwired.” However, they soon realized that the millions of things our nervous system can do would require more hardwired circuits than it could possibly contain.
An innovative neuroscientist named Eve Marder had a completely different theory for how our nervous systems work, and to prove it, she needed—of all things—crab stomachs. She focused on the stomatogastric ganglion (STG), a group of about 30 neurons connected to a crustacean’s stomach. The STG neurons control chewing, and one nice thing about them is that they keep doing their thing even when they’re taken out of the organism and studied in a lab.
Marder’s research showed that the nervous system is capable of adapting to its environment and able to keep working as it’s being repaired, without an impossible number of hardwired circuits. This was a mystery that she was determined to solve. Eve Marder researched how neuromodulators - molecules that influence what neurons do, such as the neurotransmitter dopamine - affect the activity of neurons. At the time, most neuroscientists thought of neuromodulators as working on individual neurons, like a bucket brigade passing a signal along to create a behavior. However, Marder discovered that neuromodulators were influencing the entire group of neurons together, allowing each neuron to have a slightly different reaction to the same molecule. This meant that a simple neural circuit could produce a variety of outcomes.
Marder’s research showed how fine-tuned behavior can be achieved without needing a nearly infinite number of neural connections, and how different individuals can produce the same behavior. By studying wild crustaceans, Marder was able to explore how different circuits can still result in the same behavior, even if some of the individual crabs had connections between some of their neurons that were six times stronger than other crabs.
Marder’s insights have been used to investigate problems with the human nervous system, such as stroke treatment. When someone experiences a stroke, part of their brain gets cut off from blood flow and oxygen, causing neurons to die. Marder’s research could help researchers figure out how to rebuild new connections to fill in the gaps more efficiently.
For her work describing how nervous systems both change and stay the same, Eve Marder was awarded the 2016 Kavli Prize in Neuroscience. Her research shows that when we think about things differently, entirely new pathways are possible. The Kavli Prize in Neuroscience is awarded for outstanding achievement in advancing our knowledge and understanding of the brain and nervous system. They also award a nanoscience and astrophysics prize, honoring researchers for transforming our understanding of the science of atomic, molecular and cellular structures, and advancing our knowledge of the origin, evolution and properties of the universe. If you want to learn more about Dr.Marder’s work, you can visit her page on the Kavli Prize website by clicking the link in the description.