Acts feature based suppression of ignored stimuli globally or locally in the visual field?

A key property of feature-based attention is global facilitation of the attended feature throughout the visual field. However, the question to what extend suppression of unattended features acts globally as well is still a matter of controversial results. We presented superimposed randomly moving red and blue dot kinematograms (RDKs) flickering at a different frequency each to elicit frequency specific steady-state visual evoked potentials (SSVEP) in the center of the screen and a red and blue RDK in the left and right periphery, respectively. Subjects shifted attention to one color of the superimposed central RDKs to detect coherent motion events in the attended color RDK, while the peripheral RDKs were task irrelevant. We found global facilitation of the attended color but suppression was restricted to the location of focused attention. We replicated our previous result: shifting of processing resources followed a bi-phasic process with a leading enhancement of the attended RDK followed by suppression of the unattended RDK. Our results are based on a pre-cue baseline serving as reference for post-cue SSVEP analysis. Other reference measures, like a neutral color (Painter et al., 2014), probe stimuli (Moher et al., 2014; Zhang and Luck, 2009), or no baseline reference (Störmer and Alvarez, 2014) resulted in a different pattern of effects. While some results suggested global suppression relative to the reference measure, others suggest local suppression, hampering conceptual advancement. Thus, providing solutions for a common and unique reference frame seems to be an important challenge for future studies to uncover neural dynamics in visual attention in general. Meeting abstract presented at VSS 2017