The human brain is jampacked with neurons—86 billion of them—connected in a vast, complex network that controls how we move, think, talk and make memories. Vital information is exchanged across this network through trillions of connection points, called synapses. Every neuron is continually bombarded with thousands of signals via these synapses—some important and some unimportant—but scientists still don’t fully understand how the receiving neuron extracts the relevant information.