Dynamic representations of visual space for perception and action

Abstract

The division of labor in visual processing between two anatomically relatively separate cortical pathways, a ventral and a dorsal stream, has been hotly debated in the last decades. One influential model is the What & How pathway model, suggesting that the separation is along ventral perception versus dorsal action, although the degree of functional separation between the two streams is controversial. An implication of this model is that perception and memory-guided movements are highly sensitive to visual contextual illusions, whereas visually-guided movements are largely immune to them. Here, we summarize our recent behavioral and imaging data obtained in single and double saccade paradigms that test this proposal, with a focus on the role of time in visuomotor processing and updating. We describe results showing that presentation time of the illusion affects both saccade amplitude and perceptual judgments in a similar way. We also discuss behavioral findings showing that visuomotor updating is affected by illusory context. Complementary neuroimaging data suggest a neural correlate of these findings in dorsal stream areas. Taken together, these results are suggestive of a dynamic, common visual representation that drives both perception and action, or - at least - that there is no absolute functional specialization of the two visual processing streams.

A review of grasping as the movements of digits in space

“…Studies that use other designs than relating maximum grip aperture in grasping with size perception, however, show very little evidence for separate processing for perception and action (Smeets and Brenner 2001a). Examples are motion perception and interception (de la Malla et al 2018), size illusions and goal-directed hand movements (de Grave et al 2009), and size illusions and saccades (Medendorp et al 2018).…”

“…We are, therefore, not surprised to see that many studies find little effect of size illusions on grasping (e.g., Whitwell et al 2018), although we do not regard studies that report otherwise (e.g., Kopiske et al 2016) as evidence against the two-visual-systems hypothesis either. We will not discuss the two-visual-systems hypothesis itself here (see for recent reviews: de Haan et al 2018; Goodale and Milner 2018;Medendorp et al 2018;Schenk and Hesse 2018) but will discuss what some grasping studies that were designed to test the validity of the two-visual-systems hypothesis can tell us about the control of grasping.…”

The faster you decide, the more accurate localization is possible: Position representation of “curveball illusion” in perception and eye movements

“…However, this temporal dependency was somewhat different from that in other types of illusions. For example, the effect of the Muller-Lyer illusion (on the length of a shaft caused by the direction of the arrow at either end) depends on the length of the presentation time, not on memory retention time, in both perception and saccades ([ 16 , 35 ]; see [ 15 ] for a review). The illusion effect was larger with a short presentation time and became smaller when the presentation time exceeded 200 ms.…”

Spatial coding for memory-guided reaching in visual and pictorial spaces

“…These results were supported by studies showing that memory-guided movements processed by the ventral stream are susceptible to visual illusions, whereas real-time movements processed by the dorsal stream are unaffected (Hu & Goodale, 2000;Westwood & Goodale, 2003). In contrast, recent evidence suggests that the dorsal pathway also contributes to allocentric coding, and explains actions that are susceptible to visual illusions as well (Adam, Bovend'Eerdt, Schuhmann, & Sack, 2016;de la Malla, Brenner, de Haan, & Smeets, 2019;Freud, Plaut, & Behrmann, 2016;Kravitz, Saleem, Baker, & Mishkin, 2011;Medendorp, de Brouwer, & Smeets, 2018). Based on these neurophysiological accounts, the vision-for-action/dorsal pathway could become more important in spaces that are relevant for our actions (visual space), and in turn increases the use of task-relevant objects for allocentric coding.…”