Optogenetics : Manipulating Neural Circuit Components Using Light
The human brain is an extraordinarily complex neural machine comprising approximately 1011 neurons; an average neuron is directly connected to at least 500 other neurons, thus resulting in roughly 50 trillion different connections. Somehow these billions of nerves cells wire up during development and then function as a cohesive, but continuously changing, circuit that is responsible for our actions, feelings, memory, and thoughts. Adding to this complexity is the fact that there are thousands of neuronal cell types, each with different molecular, cellular, and computational properties. Neuroscientists trying to decipher the brain's circuitry are confronted with the challenge of selectively finding and then controlling individual circuit components embedded within a soup of entangled neurons.