"Everything we and other animals do is caused by electrical signals in nerve cells, or neurons. Neurons are organized into circuits, like the electrical circuits that run electronic devices. This book explores how these circuits function to control behaviors. In some circuits, a single neuron acts like a dictator, gathering information from many sources, making decisions, and issuing commands to produce movements, such as fish and crayfish escape maneuvers. In other circuits, a large population of neurons collectively votes, with no single neuron dominating, mediating color perception, for example, and controlling eye and hand movements to objects of interest. Neural circuits control all behaviors, from the simple and automatic to the complex and deliberative. Some of the most critical circuits generate rhythmic outputs that make an animal breathe, chew, digest, walk, run, swim, or fly. These central nervous system circuits can churn out rhythmic signals on their own, like central government programs, but modify output to match demand, using feedback signals from moving body parts. To select the right behavior for each moment, nervous systems use sophisticated sensory surveillance. For example, owl circuits calculate the precise locations of sound sources to catch mice in the dark. Bats catch flying insects by emitting ultrasonic pulses and using specialized circuits to analyze the echoes, a form of sonar. Central nervous systems keep track of their own movement commands to update the surveillance circuits. Although some neural circuits are innate, others, such as those producing human speech and bird song, depend on learning, even in adulthood."--Provided by publisher. Read more...
