Pathologies of brain attentional networks

In the last decade, it has been possible to trace the areas of the human br ain involved in a variety of cognitive and emotional processes by use of im aging technology. Brain networks that subserve attention have been describe d. It is now possible to use these networks as model systems for the explor ation of symptoms arising from various forms of pathology. For example, we can use the orienting network to understand the effects of lesions that pro duce neglect of sensory information either by brain damage or by restrictin g transmitter input. Frontal attention networks may provide similar underst anding of pathologies at higher levels of cognition. Evidence relating thes e networks to attention deficit and hyperactivity disorder (ADHD) is consid ered. (C) 2000 Elsevier Science Ltd. All rights reserved.