If attention is something you pay, then the cash register is in the cortex, the topmost layer of tissue that forms the thinking part of the brain. And the currency is nore-pinephrine, a neurotransmitter that turns the register on and keeps it humming.
Scientists studying the links between the brain and behavior find that attention is a general activity of the brain, but it does not entail a general improvement in all brain systems involved in stimulus processing. Rather, observes Michael Posner, Ph.D., it is conducted by a designated network of neurons performing specific tasks in specific locations. His studies suggest that nore-pinephrine is so central to the operation of this network that a blockage somewhere along the way may lead to attention deficit disorder, marked by inability to maintain attention.
Head of the Center for the Cognitive Neuroscience of Attention, based at the University of Oregon, Posner has conducted positron emission tomography (PET) studies of normal persons responding to various stimuli. Reported in Current-Directions (Vol. 1, No. 1), the studies show there are two main centers of attention functions: