By PT Staff, published on July 1, 1992 - last reviewed on June 20, 2012
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:
Posterior parietal lobe of the cortex. First in play, it is crucial to orienting visual attention and shifting it from one location to another. It improves the efficiency of information gathering at any location by enhancing the function of individual brain cells, seen in increased blood flow during PET scans. This area recognizes patterns, visual word forms.
Right frontal cortex. This area is crucial to maintaining alertness, as shown by activation on PET scans during tests of sustained vigilance. The area also detects meaning in language, other modalities. An alerting network, made up of fibers that respond to nore-pinephrine, links the two areas from back to front. The neurotransmitter provokes the system to pick up sensory signals and detect new targets. Posner believes that attention deficit disorder may result from damage to this alerting network.
PHOTO (COLOR): PET scan of a resting brain.