What constitutes an efficient reference frame for vision?

Abstract

Vision requires a reference frame. To what extent does this reference frame depend on the structure of the visual input, rather than just on retinal landmarks? This question is particularly relevant to the perception of dynamic scenes, when keeping track of external motion relative to the retina is difficult. We tested human subjects' ability to discriminate the motion and temporal coherence of changing elements that were embedded in global patterns and whose perceptual organization was manipulated in a way that caused only minor changes to the retinal image. Coherence discriminations were always better when local elements were perceived to be organized as a global moving form than when they were perceived to be unorganized, individually moving entities. Our results indicate that perceived form influences the neural representation of its component features, and from this, we propose a new method for studying perceptual organization.According to the laws of physics, the position and motion of an object can only be defined relative to some reference frame. Neural representations of visual position and motion must abide by the same principles as physical motion, but what is the nature of the reference frame in which the visual system attains efficient representation of position and motion? The nervous system receives visual information in retinocentric coordinates; then this information is transformed into head-centered coordinates for stable perception during eye movements and into a body-centered reference frame to link perception and action [1][2][3] . Depending on the reference frame, neural representations of motion can be more or less accurate (veridical with respect to the physical world) and more or less efficient (computationally complex). Analogously, planetary motions are both more accurate and more efficient when represented in a heliocentric, rather than a geocentric, reference frame.Retinal coordinates, along with eye-position correction, are often assumed to be the primary reference frame for neural representations of position and motion. The spatial layout of photoreceptors in the retina is replicated throughout the anatomical hierarchy of visual areas as retinotopically organized maps 4 . This retinotopic organization preserves the original retinal coordinates, which could serve as the reference frame for encoding the motion and position of objects. In the human visual system, however, the motion of an object on the

Temporal properties in masking biological motion

“…Yet even inverted walkers are easier to detect with some mask phase offsets, although improvement is not as great as for upright walkers. This finding is consistent with the notion that some form information, albeit degraded, about inverted walkers is available to the visual system (e.g., see Tadin et al, 2002).…”

“…Form, however, also influences coherence judgments. Tadin, Lappin, Blake, and Grossman (2002) showed that coherence judgments were better when the local elements carrying the coherence signal were organized as a global moving form, such as upright biological motion, than when the local elements created inverted biological motion.…”

Tempo Rubato : Animacy Speeds Up Time in the Brain

“…Several previous observations might be reconciled within our proposed framework that vision of human and inanimate motions may exert differential top-down influences on automatic processes computing time. Thus, it is known that vision of upright point-light human movement enhances the detection of coherence of local dot motion above the level attained during vision of upside-down movement [36]. Vision of upright human movement also enhances the detection of rolling motion [37], and suppresses perceptual asynchronies in detecting motion onset and colour/form onset [38].…”

Suppressive mechanisms in visual motion processing: From perception to intelligence

“…The answer to this question is important not only for our understanding of motion perception, but also for elucidation of basic principles that underlie visual processing in general. While various types of visual cues can help guide integration and segregation of motion signals (Rivest & Cavanagh, 1996; Croner & Albright, 1997, 1999; Lorenceau & Alais, 2001; Tadin et al, 2002), the quality of sensory signals per se is an important factor determining the appropriate balance between integrating and differentiating processes (Faisal, Selen & Wolpert, 2008; Rubin, Van Hooser & Miller, 2015). Research by the author and other groups (Section 3.2) shows that the nature of spatial integration of motion adapts to visual conditions, with spatial summation giving way to spatial suppression as stimulus saliency increases.…”