Rutgers University
152 Frelinghuysen Road
Room A127
Piscataway, NJ 08854-8020

(732) 445-6533
FAX: (732) 445-6715

papathom@rci.rutgers.edu

website

Human and machine vision
Neural mechanisms in vision
Image processing, imaging systems, and scientific visualization techniques.
Mechanisms that underlie the perception of visual motion, stereopsis, texture, and the deployment of attention in vision

• Psychophysical experiments in vision and audition
• fMRI
• Computational neural models
• Image processing and visualization techniques

Feature-based attention affects the processing of the selected feature throughout the visual field. We showed that such global attentional modulation is not restricted to the attended feature but spreads to task-irrelevant features that are bound to the attended one. This cross-feature global attentional selection increased the strength of fMRI responses in the motion-sensitive area MT+. These findings imply that features belonging to the same object are bound and selected jointly even outside the focus of attention (published in Neuroreport, 2005). In addition, we showed that directing attention to a specific color of an object results in attentional modulation of the processing of task-irrelevant and not consciously perceived motion signals that are spatiotemporally associated with this color throughout the visual field. Such implicit cross-feature spreading of attention takes place according to the veridical physical associations between the color and motion signals, even under special circumstances when they are perceptually misbound. These results imply that the units of implicit attentional selection are spatiotemporally co-localized feature clusters that are automatically bound throughout the visual field. This article was placed on the cover page, Neuron, 2005, and featured on NPR (National Public Radio). We obtained similar evidence in experiments that demonstrated the binding of color and motion in early stages of brain processing (published in the European Journal of Neuroscience, 2005).

We used realistic three-dimensional (3-D) stimuli of a hollow mask and a scene that produce an illusory volumetric percept. We observed that the illusion is weakened when the stimuli are inverted, suggesting the involvement of top down processes. This inversion effect is stronger for the facial than the scene stimulus. These results support the hypothesis that configural processing is stronger for the 3-D perception of faces than it is for scenes, and extend the conclusions of earlier studies on 2-D stimuli (published in Perception, 2004)

For complete list: PubMed

Sohn, W., Chong, .S.C, Papathomas, T.V., Vidnyanszky, Z. (2005) Cross-feature spread of global attentional modulation in human area MT+. Neuroreport.

Melcher, D., Papathomas, T.V., Vidnyanszky, Z. (2005) Implicit attentional selection of bound visual features. Neuron 46: 723-729.

Blaser, E., Papathomas, T.V., Vidnyanszky, Z. (2005) Binding of visual motion and color is local and automatic. European Journal of Neuroscience 21: 2140-2144.

Papathomas, T.V., Bono, L. (2004) Experiments with a hollow mask and a reverspective: Top-down influences in the inversion effect for 3-D stimuli. Perception 33: 1129-1138.

Sohn, W., Papathomas, T.V., Blase, E., Vidnyanszky, Z. (2004) Object-based cross-attribute attentional modulation from color to motion. Vision Research, 44: 1437-1443.

Morikawa, C. and Papathomas, T.V. (2002) Influences of motion and depth on lightness induction: An illusory transparency effect. Perception 31: 1449-1458 .

Papathomas, T.V. (2002) Experiments on the role of pictorial cues in Hughes’ reverspectives. Perception 31: 521-530.

Vidnyanszky, Z.., Blaser, E. and Papathomas, T.V. (2002) Motion integration during motion aftereffects. Trends in Cognitive Science 6: 157-161.