Attention to Surfaces Modulates Motion Processing in Extrastriate Area MT

Abstract

In the visual system, early atomized representations are grouped into higher-level entities through processes of perceptual organization. Here we present neurophysiological evidence that a representation of a simple object, a surface defined by color and motion, can be the unit of attentional selection at an early stage of visual processing. Monkeys were cued by the color of a fixation spot to attend to one of two transparent random-dot surfaces, one red and one green, which occupied the same region of space. Motion of the attended surface drove neurons in the middle temporal (MT) visual area more strongly than physically identical motion of the non-attended surface, even though both occurred within the spotlight of attention. Surface-based effects of attention persisted even without differential surface coloring, but attentional modulation was stronger with color. These results show that attention can select surface representations to modulate visual processing as early as cortical area MT.

Object-based attention: A tutorial review

“…Wannig et al (2007) cued monkeys to attend to one of two transparent random-dot surfaces and found that the motion of the attended surface activated the neurons in MT more strongly than the motion of the unattended surface, even though the two surfaces occupied the same spatial region. These results provide a direct link between attention to an object or surface and increased neural activation of the representations of the selected object or surface in early sensory areas.…”

Object-based Selection of Irrelevant Features Is Not Confined to the Attended Object

“…Attention is conceived of being focused after the object has transferred its processing bias to all, even task-irrelevant features (Chen & Cave, 2006). Indeed, neurophysiological studies have provided broad support for this by showing that task-irrelevant object features gain privileged neural processing simply by virtue of being part of the attended object (Katzner, Busse, & Treue, 2009;Wannig, Rodriguez, & Freiwald, 2007;Schoenfeld et al, 2003;OʼCraven, Downing, & Kanwisher, 1999;ValdesSosa, Bobes, Rodriguez, & Pinilla, 1998). Notably, such object-controlled biasing of features is equivalent to the notion that attention serves to bind features for target identification put forward by influential theories on visual search ( Wolfe & Bennet, 1997;Treisman, 1988), which posit that it is focal attention that establishes the unity of an object by linking loosely bundled features (object file), thereby making their presence in the object consciously reportable ( Wolfe & Bennet, 1997;Kahneman, Treisman, & Gibbs, 1992;Treisman, 1988;Kahneman & Treisman, 1984).…”

Pupil size reflects the focus of feature-based attention

“…Some authors have suggested that shifts of spatial attention are tightly linked to eye movements (Corbetta 1998;Kowler et al 1995;Moore and Fallah 2004), so much that the two may rely on the same neural circuits (Kustov and Robinson 1996;Rizzolatti et al 1994), although there is evidence against this (Gregoriou et al 2012;Ignashchenkova et al 2004;Juan et al 2004). However, attention can also be deployed based on nonspatial criteria, as in "global feature-based attention" (Martinez-Trujillo and Treue 2004;Saenz et al 2002;Serences and Boynton 2007;Treue and Martinez Trujillo 1999) or "surface/ object-based attention" (Ernst et al 2013;He and Nakayama 1995;O'Craven et al 1997;Valdes-Sosa et al 2000;Wannig et al 2007). Being spatially distributed, this type of attention is fundamentally distinct from eye movements, and its control likely depends on separate neural circuits (Greenberg et al 2010;Maunsell and Treue 2006;Runeson et al 2013), although different types of attention may ultimately affect visual responses through similar mechanisms (Maunsell and Treue 2006;McAdams and Maunsell 1999;Reynolds and Chelazzi 2004).…”