Neuro-Cosmology

dish_milkyway

Are there equally as many neurons in the human brain as stars in the Milky Way? Bradley Voytek provides the latest data on the subject, then walks us through how scientists arrived at the numbers:

Even though we can’t conceive of the number of stars in the Milky Way or the number of neurons in the human brain, equating the two gives people a sense of enormity. And as conscious beings we like to find patterns, and we find equivalencies interesting, especially when the things being equated are “important” or “epic” (like neurons and stars).

For a long time, neuroscientists would say that there are about 100 billion neurons in the human brain. Interestingly, no one has ever published a peer-reviewed scientific paper supporting that count. Rather it’s been informally interpolated from other measurements. A recent study from 2009 published by Azevedo and colleagues took a crack at a more precise estimate. Their answer?

Approximately 86 billion neurons in the human brain. The latest estimates for the number of stars in the Milky Way is somewhere between 200 and 400 billion. So close, but the human brain certainly doesn’t quite stack up!

(Image: Infrared image of core of Milky Way galaxy, NASA/JPL-Caltech/S. Stolovy (SSC/Caltech), via Wikimedia Commons)