The rotating reference frame transformation in μSR

1991 ◽  
Vol 65 (1-4) ◽  
pp. 1107-1111 ◽  
Author(s):  
Tanya M. Riseman ◽  
Jess H. Brewer
Keyword(s):  
Reference Frame ◽  
Reference Frame Transformation ◽  
Rotating Reference Frame ◽  
Frame Transformation

Human Oculomotor System Accounts for 3-D Eye Orientation in the Visual-Motor Transformation for Saccades

1998 ◽  
Vol 80 (5) ◽  
pp. 2274-2294 ◽  
Author(s):  
Eliana M. Klier ◽  
J. Douglas Crawford
Keyword(s):  
Reference Frame ◽  
Oculomotor System ◽  
Gaze Direction ◽  
Eye Position ◽  
Look Up Table ◽  
Listing's Law ◽  
Listing’S Law ◽  
Reference Frame Transformation ◽  
Visual Motor ◽  
Frame Transformation

Klier, Eliana M. and J. Douglas Crawford. Human oculomotor system accounts for 3-D eye orientation in the visual-motor transformation for saccades. J. Neurophysiol. 80: 2274–2294, 1998. A recent theoretical investigation has demonstrated that three-dimensional (3-D) eye position dependencies in the geometry of retinal stimulation must be accounted for neurally (i.e., in a visuomotor reference frame transformation) if saccades are to be both accurate and obey Listing's law from all initial eye positions. Our goal was to determine whether the human saccade generator correctly implements this eye-to-head reference frame transformation (RFT), or if it approximates this function with a visuomotor look-up table (LT). Six head-fixed subjects participated in three experiments in complete darkness. We recorded 60° horizontal saccades between five parallel pairs of lights, over a vertical range of ±40° ( experiment 1), and 30° radial saccades from a central target, with the head upright or tilted 45° clockwise/counterclockwise to induce torsional ocular counterroll, under both binocular and monocular viewing conditions ( experiments 2 and 3). 3-D eye orientation and oculocentric target direction (i.e., retinal error) were computed from search coil signals in the right eye. Experiment 1: as predicted, retinal error was a nontrivial function of both target displacement in space and 3-D eye orientation (e.g., horizontally displaced targets could induce horizontal or oblique retinal errors, depending on eye position). These data were input to a 3-D visuomotor LT model, which implemented Listing's law, but predicted position-dependent errors in final gaze direction of up to 19.8°. Actual saccades obeyed Listing's law but did not show the predicted pattern of inaccuracies in final gaze direction, i.e., the slope of actual error, as a function of predicted error, was only −0.01 ± 0.14 (compared with 0 for RFT model and 1.0 for LT model), suggesting near-perfect compensation for eye position. Experiments 2 and 3: actual directional errors from initial torsional eye positions were only a fraction of those predicted by the LT model (e.g., 32% for clockwise and 33% for counterclockwise counterroll during binocular viewing). Furthermore, any residual errors were immediately reduced when visual feedback was provided during saccades. Thus, other than sporadic miscalibrations for torsion, saccades were accurate from all 3-D eye positions. We conclude that 1) the hypothesis of a visuomotor look-up table for saccades fails to account even for saccades made directly toward visual targets, but rather, 2) the oculomotor system takes 3-D eye orientation into account in a visuomotor reference frame transformation. This transformation is probably implemented physiologically between retinotopically organized saccade centers (in cortex and superior colliculus) and the brain stem burst generator.

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.

Evaluation of Combined Reference Frame Transformation for Interturn Fault Detection in Permanent-Magnet Multiphase Machines

2015 ◽  
Vol 62 (3) ◽  
pp. 1912-1920 ◽  
Author(s):  
Fabio Immovilli ◽  
Claudio Bianchini ◽  
Emilio Lorenzani ◽  
Alberto Bellini ◽  
Emanuele Fornasiero
Keyword(s):  
Fault Detection ◽  
Permanent Magnet ◽  
Reference Frame ◽  
Reference Frame Transformation ◽  
Frame Transformation
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