It seems our brains are never truly quiet. We dream when we are asleep, and in sensory deprivation experiments, participants start hallucinating within 15 minutes. Where does this spontaneous activity in our brains come from? "My contention is, based on experiments and computational models, that spontaneous activity is triggered by what is called 'noise,'" said Roberto Galan. Galan is an adjunct associate professor in electrical engineering at Case Western Reserve University. He studies how our