Visually-guided auditory adaptation and reference frame of the ventriloquism after effect

2017 ◽  
Vol 141 (5) ◽  
pp. 3895-3895
Author(s):  
Peter Lokša ◽  
Norbert Kopco
Keyword(s):  
Reference Frame ◽  
Visually Guided ◽  
Auditory Adaptation ◽  
After Effect

Reference Frames for Reach Planning in Macaque Dorsal Premotor Cortex

2007 ◽  
Vol 98 (2) ◽  
pp. 966-983 ◽  
Author(s):  
Aaron P. Batista ◽  
Gopal Santhanam ◽  
Byron M. Yu ◽  
Stephen I. Ryu ◽  
Afsheen Afshar ◽  
...  
Keyword(s):  
Reference Frame ◽  
Reference Frames ◽  
Premotor Cortex ◽  
Visually Guided ◽  
Electrode Arrays ◽  
Reference Frame Transformation ◽  
Frame Transformation ◽  
Visual Reference Frame ◽  
Reach Planning ◽  
The Brain

When a human or animal reaches out to grasp an object, the brain rapidly computes a pattern of muscular contractions that can acquire the target. This computation involves a reference frame transformation because the target's position is initially available only in a visual reference frame, yet the required control signal is a set of commands to the musculature. One of the core brain areas involved in visually guided reaching is the dorsal aspect of the premotor cortex (PMd). Using chronically implanted electrode arrays in two Rhesus monkeys, we studied the contributions of PMd to the reference frame transformation for reaching. PMd neurons are influenced by the locations of reach targets relative to both the arm and the eyes. Some neurons encode reach goals using limb-centered reference frames, whereas others employ eye-centered reference fames. Some cells encode reach goals in a reference frame best described by the combined position of the eyes and hand. In addition to neurons like these where a reference frame could be identified, PMd also contains cells that are influenced by both the eye- and limb-centered locations of reach goals but for which a distinct reference frame could not be determined. We propose two interpretations for these neurons. First, they may encode reach goals using a reference frame we did not investigate, such as intrinsic reference frames. Second, they may not be adequately characterized by any reference frame.

scholarly journals Spatial Memory Following Shifts of Gaze. I. Saccades to Memorized World-Fixed and Gaze-Fixed Targets

2003 ◽  
Vol 89 (5) ◽  
pp. 2564-2576 ◽  
Author(s):  
Justin T. Baker ◽  
Timothy M. Harper ◽  
Lawrence H. Snyder
Keyword(s):  
Reference Frame ◽  
Smooth Pursuit ◽  
Spatial Working Memory ◽  
Whole Body ◽  
Visually Guided ◽  
Gaze Shift ◽  
Representational System ◽  
The World ◽  
Spatial Locations ◽  
Sequence Characteristics

During a shift of gaze, an object can move along with gaze or stay fixed in the world. To examine the effect of an object's reference frame on spatial working memory, we trained monkeys to memorize locations of visual stimuli as either fixed in the world or fixed to gaze. Each trial consisted of an initial reference frame instruction, followed by a peripheral visual flash, a memory-period gaze shift, and finally a memory-guided saccade to the location consistent with the instructed reference frame. The memory-period gaze shift was either rapid (a saccade) or slow (smooth pursuit or whole body rotation). This design allowed a comparison of memory-guided saccade performance under various conditions. Our data indicate that after a rotation or smooth-pursuit eye movement, saccades to memorized world-fixed targets are more variable than saccades to memorized gaze-fixed targets. In contrast, memory-guided saccades to world- and gaze-fixed targets are equally variable following a visually guided saccade. Across all conditions, accuracy, latency, and main sequence characteristics of memory-guided saccades are not influenced by the target's reference frame. Memory-guided saccades are, however, more accurate after fast compared with slow gaze shifts. These results are most consistent with an eye-centered representational system for storing the spatial locations of memorized objects but suggest that the visual system may engage different mechanisms to update the stored signal depending on how gaze is shifted.

Reference frame conversions for visually-guided arm movements

2010 ◽  
Vol 6 (6) ◽  
pp. 933-933
Author(s):  
G. U. Sorrento ◽  
D. Y. P. Herniques
Keyword(s):  
Reference Frame ◽  
Arm Movements ◽  
Visually Guided

Reference Frame of Human Medial Intraparietal Cortex in Visually Guided Movements

2012 ◽  
Vol 24 (1) ◽  
pp. 171-182 ◽  
Author(s):  
Kenji Ogawa ◽  
Toshio Inui
Keyword(s):  
Reference Frame ◽  
Posterior Parietal Cortex ◽  
Activity Patterns ◽  
Target Position ◽  
The Body ◽  
Visually Guided ◽  
Reaching Task ◽  
Visually Guided Reaching ◽  
Actual Movement ◽  
Visually Guided Movements

Visually guided reaching involves the transformation of a spatial position of a target into a body-centered reference frame. Although involvement of the posterior parietal cortex (PPC) has been proposed in this visuomotor transformation, it is unclear whether human PPC uses visual or body-centered coordinates in visually guided movements. We used a delayed visually guided reaching task, together with an fMRI multivoxel pattern analysis, to reveal the reference frame used in the human PPC. In experiments, a target was first presented either to the left or to the right of a fixation point. After a delay period, subjects moved a cursor to the position where the target had previously been displayed using either a normal or a left–right reversed mouse. The activation patterns of normal sessions were first used to train the classifier to predict movement directions. The activity patterns of the reversed sessions were then used as inputs to the decoder to test whether predicted directions correspond to actual movement directions in either visual or body-centered coordinates. When the target was presented before actual movement, the predicted direction in the medial intraparietal cortex was congruent with the actual movement in the body-centered coordinates, although the averaged signal intensities were not significantly different between two movement directions. Our results indicate that the human medial intraparietal cortex uses body-centered coordinates to encode target position or movement directions, which are crucial for visually guided movements.

Practical Realization of a Reference System for Earth Dynamics by Satellite Methods

1975 ◽  
Vol 26 ◽  
pp. 341-380 ◽  
Author(s):  
R. J. Anderle ◽  
M. C. Tanenbaum
Keyword(s):  
Reference Frame ◽  
Polar Motion ◽  
Pole Position ◽  
Control Points ◽  
Significant Information ◽  
Crustal Motion ◽  
Average Reference ◽  
Future Data ◽  
Existing Data

AbstractObservations of artificial earth satellites provide a means of establishing an.origin, orientation, scale and control points for a coordinate system. Neither existing data nor future data are likely to provide significant information on the .001 angle between the axis of angular momentum and axis of rotation. Existing data have provided data to about .01 accuracy on the pole position and to possibly a meter on the origin of the system and for control points. The longitude origin is essentially arbitrary. While these accuracies permit acquisition of useful data on tides and polar motion through dynamio analyses, they are inadequate for determination of crustal motion or significant improvement in polar motion. The limitations arise from gravity, drag and radiation forces on the satellites as well as from instrument errors. Improvements in laser equipment and the launch of the dense LAGEOS satellite in an orbit high enough to suppress significant gravity and drag errors will permit determination of crustal motion and more accurate, higher frequency, polar motion. However, the reference frame for the results is likely to be an average reference frame defined by the observing stations, resulting in significant corrections to be determined for effects of changes in station configuration and data losses.

How Do Task Instructions Alter the Spatial Reference Frame of Scene-Based Processing?

2011 ◽  
Author(s):  
Mark Mills ◽  
Stefan Van Der Stigchel ◽  
Andrew Hollingworth ◽  
Michael D. Dodd
Keyword(s):  
Reference Frame ◽  
Spatial Reference ◽  
Task Instructions ◽  
Spatial Reference Frame
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