Attention is the process by which certain information is selected for further processing and other information is discarded. In general, when an object or perceptual feature is attended there is an increased activity, measured with functional magnetic resonance imaging, in brain regions that are involved in perceiving those stimuli relative to when they are unattended. These biasing signals originate from parietal regions (typically spatially organized) and frontal regions (which controls task-relevance). Theories of attention differ according to whether they are early selection (prioritizing information based on sensory information) or late selection (prioritizing information based on meaning) or both. Brain damage to the right parietal lobe can lead to problems attending to the left side of space and this is called neglect. Neglect can affect different aspects of spatial attention providing evidence for different specialized processes.
