Three experiments investigated the frame of reference used in memory to represent vertical spatial layouts perceivable from a single viewpoint. We tested for the selection of three different reference systems: the body orientation, the visual vertical of the surrounding room, and the direction of gravity. Participants learned and retrieved differently colored objects on a vertical board with bo...

In this paper, we design an adaptive kinematic controller that asymptotically regulates a robot end-effector to a desired position and orientation under visual feedback (of points located on a fixed reference frame) from a camera mounted on the end-effector. This task is accomplished despite lack of depth measurements as well as uncertainty in the camera intrinsic parameter matrix.

Reference frames in spatial memory encoding have been examined intensively in recent years. However, their importance for recall has received considerably less attention. In the present study, passersby used tags to arrange a configuration map of prominent city center landmarks. It has been shown that such configurational knowledge is memorized within a north-up reference frame. However, partic...

An intriguing question in neuroscience concerns how somatosensory events on the skin are represented in the human brain. Since Head and Holmes' [1] neuropsychological dissociation between localizing touch on the skin and localizing body parts in external space, touch is considered to operate in a variety of spatial reference frames [2]. At least two representations of space are in competition d...

We analyse here people's perception of their reflections in mirrors placed in different positions. In two experiments, participants looked at their mirror image, in a third experiment they looked at another person's image. In both cases they were asked to answer a series of questions about how the virtual body appeared relative to the real body, focusing on different aspects. In experiment 1, t...

We represent behaviorally relevant information in different spatial reference frames in order to interact effectively with our environment. For example, we need an egocentric (e.g., body-centered) reference frame to specify limb movements and an allocentric (e.g., world-centered) reference frame to navigate from one location to another. Posterior parietal cortex (PPC) is vital for performing tr...

The supplementary eye field (SEF) is a region within medial frontal cortex that integrates complex visuospatial information and controls eye-head gaze shifts. Here, we test if the SEF encodes desired gaze directions in a simple retinal (eye-centered) frame, such as the superior colliculus, or in some other, more complex frame. We electrically stimulated 55 SEF sites in two head-unrestrained mon...

Interaction in Immersive Virtual Environments (VEs) is fundamentally driven by the physical actions of the user’s body. The location of rendered virtual objects is, in contrast, the free choice of the VE application designer. The goal of Dmitri Lemmerman’s masters degree project is to explore the effect of the position of rendered graphical “widgets” on user performance in the use of those widg...

Detection of a uniquely oriented line element in a background field of uniformly oriented line elements depends on the orientation of the background field. Is the orientational reference frame for this anisotropy entirely dependent on the orientations of structures outside the line-element display, the spatial regularity of the stimulus elements, and the direction of gravity? The effects of the...