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Uncovering the brain's biggest secret - Melanie E. Peffer

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In the 1860s, scientists believed they were on the verge of uncovering the brain’s biggest secret: how the brain’s signals travel through the body. They believed these impulses travelled uninterrupted along a massive web of tissue. But soon, a young artist would cut down this hypothesis, and sketch a bold new vision of how our brains work. Melanie Peffer details the discoveries of Golgi and Cajal.

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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Melanie E. Peffer
  • Director Igor Coric, Artrake Studio
  • Narrator Bethany Cutmore-Scott
  • Director of Production Gerta Xhelo
  • Editorial Director Alex Rosenthal
  • Producer Bethany Cutmore-Scott
  • Editorial Producer Dan Kwartler
  • Script Editor Emma Bryce
  • Fact-Checker Jennifer Nam
  • See more creators
Additional Resources for you to Explore
The 1906 Nobel Prize in Physiology or Medicine was shared by Camillo Golgi and Santiago Ramon y Cajal. They were recognized for their work deciphering the structure of the nervous system. Although Golgi and Cajal shared the award, they were actually rivals. They had opposing views of how the nervous system was structured. In fact, their Nobel laureate lectures contradicted one another. Golgi thought that the nervous system was made up of a single continuous structure of filaments. Cajal thought that the nervous system was not made up of continuous fibers, but rather single cells. Why is it that two scientists could look at the same data and come up with different conclusions?

This story illustrates how science really works in the real world. A common way of thinking about science is that it follows a recipe-like format, or the “scientific method” and that we use this method for generating new information about the world. In the real world, science is far more exciting and interesting – in fact, there are many different kinds of scientific methods depending on what a scientist is studying. What makes science knowledge special is not necessarily how it was generated, but if the method used produced quality evidence. Quality evidence can be used to support a scientific claim, and then we can use those claims to make decisions.

Cajal’s new stain and observations provided new evidence that reticular theory, or that the nervous system was a single entity, wasn’t correct. Rather, the new evidence suggested something different – that cells were not in physical contact with one another and communicated through indirect electrical signals. It is normal for scientists to tweak their ideas in light of new evidence. In fact, this is a very important part of science! It’s also a normal part of science that not everyone agrees on how to interpret the same evidence. How we interpret evidence can be biased. Cognitive biases are errors that our brain makes when interpreting new information. Sometimes this can be a result of something we already know, or prior belief bias. Golgi had been studying the nervous system for many years from the perspective of reticular theory because Cajal announced his discoveries. He was biased to view evidence through the lens of reticular theory rather than the neuron doctrine.

Real world science doesn’t work in a vacuum – rather what scientists decide to test, how they test it, and how that evidence is interpreted is dictated by many outside influences. What gets studied is usually determined by what kind of grant money is available. How something is tested is often a factor of the techniques a scientist learned while in school. Evidence interpretation is influenced by cognitive biases. Culture and religion can also influence the process of science – you can learn more about bias, scientific methods, and the progress of science in this article written by Melanie Peffer. Watch this TEDx Talk by Peffer to learn about the ways science pops up in our daily lives in unexpected ways.


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About TED-Ed Animations

TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Melanie E. Peffer
  • Director Igor Coric, Artrake Studio
  • Narrator Bethany Cutmore-Scott
  • Director of Production Gerta Xhelo
  • Editorial Director Alex Rosenthal
  • Producer Bethany Cutmore-Scott
  • Editorial Producer Dan Kwartler
  • Script Editor Emma Bryce
  • Fact-Checker Jennifer Nam
  • See more creators