From Popular Mechanics earlier this week:
“Whether it was a drawing or photograph, these images changed the course of human understanding, and science itself, forever.”
Choosing just ten images would have been a very hard task, but I reckon they missed one that is as fundamentally important as any of the others (no prizes for guessing…)
This is a drawing of a single neurone by Santiago Ramón y Cajal, a spanish anatomist and histologist born in 1852. Mo Costandi has written a brilliant (and beautiful) post about The Discovery of the Neurone that’s very worth reading. On Cajal he writes
“It was Santiago Ramón y Cajal (1852-1934) who suggested that the neuron was the anatomical and functional of the nervous system, and it is largely because of his work that the Neuron Doctrine eventually came to accepted (sic). Cajal was an outstanding neuroanatomist who is regarded as the father of modern neuroscience. He made many contributions to our understanding of the organization of the nervous system”
The Neuron Doctrine contrasted with the Reticular Theory of the nervous system at the time, which suggested that the nervous system was one large network of tissue- a reticulum (from the Latin for ‘net’) formed by the fused processes of nerve cells. While the reticular theory suggested that electrical activity in the continuous net of fused neuronal tissues fired in all directions, the neuron doctrine suggested that the discrete neurons that formed the nervous system transmitted signals in one direction, receiving information at one end and transmitting this to the next cell.
As a historical side note, Cajal and the great Italian anatomist Camillo Golgi (who’s tissue staining method Cajal improved to make his discoveries) both received the Nobel Prize in 1906 in recognition of their work on the structure of the nervous system. However at the time, Gogli refused to acknowledge the neuron doctrine, continuing to support the reticular theory and used his Nobel lecture to try to discredit his co-winner’s theory*. Interestingly, while the neurone doctrine was widely accepted in 1906, it wasn’t until 1954, nearly three decades after Golgi’s death, that the first electron scanning micrograph of a neuronal synapse provided definitive and direct evidence for this structure. But, electron scanning micrographs have also provided direct evidence for electrically coupled neurons in the brain via gap junctions that may form regions at least, of a reticular like network (damn science, why does it always have to be shades of grey).
While the neurone doctrine has been refined and improved since it’s first postulation, with exceptions to it’s ‘rules’ discovered, the basic notions paved the way for modern neuroscience and our understanding of the nervous system.
The image of the neurone as a discrete functional unit of the nervous system has led to discoveries that have fundamentally changed the way we understand the brain, the entire nervous system and not just how we look at the world, but also how we look at the world.
But I’m not willing to suggest that any of those other ten be knocked out so I’ll suggest that the list should be 11 Scientific Images that Changed How we Looked at the World**.
* For those interested, Cajal’s own lecture is considered to be a graceful response, and can be read here.
Learn about the “gift of the synapse” and dozens of other neuroscience nuggets as you get your think on and get up to date at a noigroup course. Alternatively you can read all about neurones – including backfiring ones, and the brain and immerse yourself in some brainy books with Explain Pain 2nd Ed and The Graded Motor Imagery Handbook