Artificial Neural Network and Machine Learning have become hot topics in the popular media. The idea of intelligent machines captivates the imagination of many, and especially how they would compare to humans. Specifically, one fundamental question that seems to come up frequently is about the underlaying mechanisms of intelligence -- do these artificial neural networks really work like the neurons in our brain? While the high level and conceptual thinking of ANNs (artificial neural networks) is inspired by neurons and neural networks in the brain, the ML implementation of these concepts has diverged significantly from how the brain works. Moreover, as the field of ML progressed over the years, and new complex ideas and techniques have been developed (RNNs, GANs, etc) -- that link has further weakened.
Throughout life, new neurons are added to the brain. Just like people arriving late to a cocktail party, the newbies need to figure out how to integrate with those already embroiled in conversations. The zebrafish brain, already capable of complex visual processing at larval stages, accepts new neurons throughout the fish life span. Boulanger-Weill et al. tracked the location, movement, and functional integration of single newborn neurons in developing zebrafish larvae. Following their own developmental trajectories, newborn neurons began with limited dendritic arbors, no neurotransmitter identity, and spontaneous, but not directed, activity.
Though ravens may have small brains, they're dense with neurons, especially their forebrains, researchers say. For years, scientists have observed behavioral abilities of birds that seem inexplicably complex and advanced for their small brain size. Corvids, the family of birds that includes crows and ravens, use tools, solve problems, and even recognize themselves in the mirror. But a raven's brain is only a little over 15 grams in weight. On average, a chimpanzee's brain weighs 420 grams.
For patients with epilepsy, or cancerous brain lesions, sometimes the only way to forward is down. Down past the scalp and into the skull, down through healthy grey matter to get at a tumor or the overactive network causing seizures. At the end of the surgery, all that extra white and grey matter gets tossed in the trash or an incinerator. For the last few years, doctors at a number of hospitals in the Emerald City have been saving those little bits and blobs of brain, sticking them on ice, and rushing them off in a white van across town to the Allen Institute for Brain Science. Scientists there have been keeping the tissue on life support long enough to tease out how individual neurons look, act, and communicate.
It started with some blobs of brain-like tissue, growing in a dish. Frank Jacobs, then at the University of California at Santa Cruz, had taken stem cells from humans and monkeys, and coaxed them into forming small balls of neurons. These "organoids" mirror the early stages of brain development. By studying them, Jacobs could look for genes that are switched on more strongly in the growing brains of humans than in those of monkeys. And when he presented his data to his colleagues at a lab meeting, one gene grabbed everyone's attention.