RT Journal Article SR Electronic T1 Spatial Attention Effects in Macaque Area V4 JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 3201 OP 3214 DO 10.1523/JNEUROSCI.17-09-03201.1997 VO 17 IS 9 A1 Connor, Charles E. A1 Preddie, Dean C. A1 Gallant, Jack L. A1 Van Essen, David C. YR 1997 UL http://www.jneurosci.org/content/17/9/3201.abstract AB Focal visual attention typically produces enhanced perceptual processing at the psychological level and relatively stronger neural responses at the physiological level. A longstanding mechanistic question is whether these attentional effects pertain specifically to the attended (target) object or to the region of space it occupies. We show here that attentional response enhancement in macaque area V4 extends to behaviorally irrelevant objects in the vicinity of the target object, indicating that focal attention has a strong spatial component at the physiological level. In addition, we find that spatial attention effects typically show a striking directional asymmetry. The direction of the asymmetry varies between cells, so that some cells respond best when attention is directed to the left of the stimulus, some when attention is directed to the right, etc. Thus, attention involves not only enhanced responses to behavioral targets but also a complex modulation of responses to other stimuli in the surrounding visual space.