Abstract
Navigation is a vital part of our daily lives, and it is important to understand the informational inputs that contribute to our sense of orientation. Path integration, the continuous updating of position and orientation during self-motion, relies on several sources of information, including vision, vestibular information, and proprioceptive input from walking. However, the relative contributions of these sources of information have not fully been determined. Homing during path integration has typically been tested using a triangle completion task, in which navigators are guided on two legs of an outbound path and then must generate a trajectory back to the start location, but this task leaves open the potential for execution errors during the homebound trajectory. Here, we introduce a novel path integration task that does not rely on integration of complex turns or execution of a homeward trajectory: the loop closure task. In the loop closure task, participants travel on a loop trajectory and indicate when they think they have traversed one full loop and had returned to the start location. To test the contributions of different sources of information to tracking position, participants completed the loop closure task while a) walking and b) sitting in a wheelchair. Those two levels of idiothetic information were crossed with i) full vision and ii) movement while blindfolded. Visual stimuli consisted of a textured ground plane presented to participants over a head-mounted display, and the experimenter guided the participant along the loop trajectories. The primary outcome measure was the distance between the actual start location of the loop and the location marked by the participant as the start. Preliminary results indicate that the smallest errors were in the walking-vision condition, followed by the walking-blindfold condition, then the two wheelchair conditions. These findings suggest that proprioceptive information is the largest contributor to path integration.
Meeting abstract presented at VSS 2017