Chapter 1 endnote 36, from Lisa Feldman Barrett.
Some context is:
This is one of the most surprising things I learned as I began to study neuroscience: a mental event, such as fear, is not created by only one set of neurons. Instead, combinations of different neurons can create instances of fear. Neuroscientists call this principle degeneracy. Degeneracy means “many to one”: many combinations of neurons can produce the same outcome.
Every day as I drive to work, I pass a billboard with the cutest photo of a baby orangutan. And every single time I see that adorable face, I feel happy and smile. Sometimes I even start smiling before I see it, because I know it’s coming up. It’s always the same feeling, on the same road, in the same car, with the same orangutan on the same billboard. So you might think that the same neurons are creating this feeling each time, but in fact they can be completely different, and yet the experience remains the same. This is an example of degeneracy, the many-to-one phenomenon discussed in How Emotions are Made.
Gerald Edelman won a Nobel prize for his work on degeneracy within the immune system, and then generalized these lessons to his later study of the brain and consciousness, which he named Neural Darwinism. The central idea is that each mental event has many degenerate neural representations that are possible and the brain selects one, similar to the way that natural selection works.
Notes on the Notes
- Edelman, Gerald M., and Joseph A. Gally. 2001. “Degeneracy and Complexity in Biological Systems.” Proceedings of the National Academy of Sciences 98 (24): 13763–13768.
- Edelman, Gerald M. 1987. Neural Darwinism: The Theory of Neuronal Group Selection. New York: Basic Books.
- Marder, E., and A. L. Taylor. 2011. “Multiple Models to Capture the Variability in Biological Neurons and Networks.” Nature Neuroscience 14: 133–138.
- Prinz, A.A., Bucher, D., and Marder, E. 2004. "Similar network activity from disparate circuit parameters." Nature Neuroscience, 7 (12): 1345-1352.
- Gjorgjieva, J., Drion, G., and Marder, E. 2016. "Computational implications of biophysical diversity and multiple timescales in neurons and synapses for circuit performance." Current Opinion in Neurobiology, 37: 44–52.
- Leonardo, Anthony. 2005. "Degenerate coding in neural systems." Journal of Comparative Physiology A 191 (11): 995-1010.
- Price, Cathy J., and Karl J. Friston. 2002. "Degeneracy and cognitive anatomy." Trends in Cognitive Sciences 6 (10): 416-421.