Attentional resolution and the locus of visual awareness
- 1 September 1996
- journal article
- Published by Springer Science and Business Media LLC in Nature
- Vol. 383 (6598), 334-337
- https://doi.org/10.1038/383334a0
Abstract
Visual spatial resolution is limited by factors ranging from optics to neuronal filters in the visual cortex, but it is not known to what extent it is also limited by the resolving power of attention. To investigate this, we studied adaptation to lines of specific orientation, a process that occurs in primary visual cortex. When a single grating is presented in the periphery of the visual field, human observers are aware of its orientation, but when it is flanked by other similar gratings ('crowding'), its orientation becomes impossible to discern. Nevertheless, we show that orientation-specific adaptation is not affected by crowding, implying that spatial resolution is limited by an attentional filter acting beyond the primary visual cortex. Consistent with this, we find that attentional resolution is greater in the lower than in the upper visual field, whereas there is no corresponding asymmetry in the primary visual cortex. We suggest that the attentional filter acts in one or more higher visual cortical areas to restrict the availability of visual information to conscious awareness.Keywords
This publication has 21 references indexed in Scilit:
- Blindsight in normal observersNature, 1995
- Borders of Multiple Visual Areas in Humans Revealed by Functional Magnetic Resonance ImagingScience, 1995
- Are we aware of neural activity in primary visual cortex?Nature, 1995
- The two-dimensional shape of spatial interaction zones in the parafoveaVision Research, 1992
- The Representation of the Visual Field in Human Striate CortexAmerican Journal of Ophthalmology, 1991
- Task and contrast effects on performance with parafoval stimulus pairsPsychological Research, 1983
- Lateral masking vertically and horizontallyBulletin of the Psychonomic Society, 1983
- Interaction Effects in Parafoveal Letter RecognitionNature, 1970
- On the existence of neurones in the human visual system selectively sensitive to the orientation and size of retinal imagesThe Journal of Physiology, 1969
- Optical quality of the human eyeThe Journal of Physiology, 1966