[Frontiers in Bioscience 6, d672-684, May 1, 2001]


Charles E. Schroeder 1,2, Ashesh D. Mehta 4 and John J. Foxe 1,3

1 Cognitive Neuroscience and Schizophrenia Program, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, New York 10962, 2 Department of Neuroscience and 3 Department of Psychiatry and Behavioural Science, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10462, 4 Department of Neurosurgery, Weill Medical College of Cornell University, East 69th Street, New York, New York 10021


1. Abstract
2. Overview
3. Attention Paradigms and their Ecological Validity
3.1. Visuospatial (non-foveal) Attention
3.2. Nonspatial Visual Attention
4. Effects of Attention on Brain Activity Measurements
4.1. Visuo-spatial attention
4.2. Nonspatial Attention
5. An anatomical hierarchy of attention effects?
6. A temporal hierarchy of attention effects?
7. Brain Mechanisms of Attentional Modulation
7.1. Neuronal circuits
7.2. Physiology
8. Linkage Between Neural Effects and the Cognitive Impact of Attention
8.1. Neuronal and perceptual amplification
8.2. Dynamic change in cellular connectivity
9. Conclusions
9.1. Toward an Adequate Model of Attention
9.1.1. Operational Dynamics
9.1.2. Perceptual and Neural Mechanisms
10. Acknowledgements
11. References


This review contrasts the most-studied variety of attention, visuospatial attention, with several types of nonspatial visual attention. We: 1) discuss the manner in which spatial and nonspatial varieties of attention are experimentally defined, and the ecological validity of the paradigms in which they are studied, 2) review and compare differing effects of spatial and nonspatial attention on neural processing, 3) discuss the manner in which attention operates within the framework of an anatomical visual hierarchy, as well as 4) how attention relates to the temporal dynamics of visual processing, 5) describe cellular circuits and physiological processes that appear to be involved in attention effects, 6) discuss the relationship of attentional physiology to the perceptual and cognitive effects of attention, and 7) consider the strengths and limitations of several current models of selective attention. Throughout, we attempt to integrate the findings of monkey and human studies whenever possible.