Brain connectome

The partial fruit fly “connectome” contains approximately 25,000 neurons and 20 million synapses

• By Diana Kwon on January 22, 2020

Electron microscope image shows neurons in the fruit fly brain. An algorithm determines where each neuron starts and ends, and human proofreaders check the algorithm’s work. Credit: FlyEM Janelia Research Campus

The brain of a common fruit fly (Drosophila melanogaster) is no larger than a poppy seed, but the miniscule piece of tissue holds tens of thousands of neurons joined by tens of millions of synapses. Although it is no rival to the human brain, which contains more than 80 billion neurons, the fly organ is still an invaluable tool for investigating the neural circuity underlying some of the basic behaviors of more complex animals. Using fruit flies, scientists have now constructed the largest brain map to date./.../