Researchers from the Karolinska Institutet believe that they have discovered specialized nerve cells which specifically control nipple erections and goose bumps. Aside from spawning amusing headlines, this finding has implications for scientific understanding of the sympathetic nervous system and how the body responds to different types of stimulation.
In Brief: Sympathetic Nerves
The sympathetic nervous system is largely beyond our conscious control. The system helps regulate daily activities and balances various important functions like the fight-or-flight response or body temperature. The prevailing understanding about the sympathetic nervous system is that it is non-specific. That is, it produces the same type of response regardless of what actually triggers it. The fight-or-flight response from a scary movie’s jump scare would be the same as being accosted by a mugger, for instance.
In response to cold temperatures, the sympathetic system will activate “erectile muscles” in the skin to raise body hair for more warmth. Since humans are not as hairy as they used to be, this ends up producing goose bumps, hard nipples, etc. What the researchers wanted to know is whether there was any specialization to the nerve cells involved in this process.
The researchers performed a large-scale investigation of the nerve cells in mice and assessed the amount of different cell types they encountered. To their surprise, they found a high level of variety. Specifically, they encountered neurons that were designed to control the skin’s erectile muscles and only those muscles. Further probing found that the neurons formed relatively early in embryonic development but did not specialize until after birth.
What This Means
The finding of these specialized nerve cells does not have any immediate clinical value. Instead, it offers an expanded image of how the body functions and is formed. The sympathetic nervous system is responsible for a great deal of daily life beyond simple goose bumps, so any effort to get a clearer idea of how this complex system works should be lauded. Plus, this study gives you an excuse to talk about nipple erections while still sounding intellectual. Enjoy!
Furlan, A., “Visceral motor neuron diversity delineates a cellular basis for nipple- and pilo-erection muscle control,” Nature Neuroscience, 2016; 10.1038/nn.4376.