Spatial Updating Depends on Gaze Direction Even after Loss of Vision

Abstract

Direction of gaze (eye angle ϩ head angle) has been shown to be important for representing space for action, implying a crucial role of vision for spatial updating. However, blind people have no access to vision yet are able to perform goal-directed actions successfully. Here, we investigated the role of visual experience for localizing and updating targets as a function of intervening gaze shifts in humans. People who differed in visual experience (late blind, congenitally blind, or sighted) were briefly presented with a proprioceptive reach target while facing it. Before they reached to the target's remembered location, they turned their head toward an eccentric direction that also induced corresponding eye movements in sighted and late blind individuals. We found that reaching errors varied systematically as a function of shift in gaze direction only in participants with early visual experience (sighted and late blind). In the late blind, this effect was solely present in people with moveable eyes but not in people with at least one glass eye. Our results suggest that the effect of gaze shifts on spatial updating develops on the basis of visual experience early in life and remains even after loss of vision as long as feedback from the eyes and head is available.

Visual Experience Determines the Use of External Reference Frames in Joint Action Control

“…To summarize, the present study extends previous findings on individual action control [9]–[10] by demonstrating the default use of external coding strategies during joint action, independent of the presence or (transient/permanent) absence of vision. Hence, changing the contextual demands of action control from individual to joint task performance seems to strengthen the reliance on external reference frames.…”

“…Hence, congenitally-blind people seem to code the stimulus location with respect to their left or right hand (internal, observer-centered coordinates), regardless of the location of the response keys, whereas people with visual experience (sighted and late-blind) preferentially code the location of the stimulus with respect to the location of the response keys (using external, response-based coordinates; see also [37]-[39], but see [40] for evidence of internal coding). Similar results have been reported recently in a goal-directed reaching task [10]. Note, that these results do not imply that congenitally-blind individuals are incapable of successfully using external reference frames, but rather point to a default use of an internal, observer-centered reference frame in individual manual tasks (e.g., [41]–[42]).…”

“…This is supported by studies with blind and sighted people demonstrating that developmental vision determines the default use of reference frames. While late-blind and sighted people preferably code space in external, environmental-centered coordinates, congenitally-blind people favor the use of internal, observer-centered coordinates [9]–[10]. Yet, it is still unclear if and how visual experience influences the use of reference frames for organizing motor control in joint action.…”

“…Since sighted and congenitally-blind people are both able to efficiently interact with others, it is conceivable that they rely on external reference frame/s (i.e., agent-based and/or response-based) when they engage in social manual tasks. However, if vision is crucially involved in the use of external spatial coordinates in joint action, as has been shown for individual action tasks [9]–[10], the use of external reference frame/s in social manual tasks may differ between sighted and congenitally-blind people. There is evidence that congenitally-blind people compensate for the lack of visual input with their remaining senses, to some extent ( compensatory hypothesis , [43]).…”

Visual Objects in the Auditory System in Sensory Substitution: How Much Information Do We Need?

“…Pasquallotto and colleagues found in a spatial task that while sighted and late blind participants showed a preferential use of an object-based or 'allocentric' reference frame, the congenitally blind participants preferred a self-based 'egocentric' refer ence frame (Pasqualotto etal., 2013b). This corresponds with ideas that at least some visual experience is a requisite of developing multisensory neurons, spa tial updating tasks, multisensory integration and higher cognition (Pasqualotto and Proulx, 2012;Reuschel et al, 2012;Wallace et al, 2004). With two algo rithm principles coding spatial factors and multisensory integration integral in SSD use, task-based comparisons between the three should feature heavily in future research.…”