Impact of Coordinate Transformation Uncertainty on Human Sensorimotor Control

Impact of Coordinate Transformation Uncertainty on Human Sensorimotor Control Erik J. Schlicht Paul R. Schrater

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Impact of Coordinate Transformation Uncertainty on Human Sensorimotor Control 2007 Journal of Neurophysiology 10.1152/jn.00160.2007 schlicht2007-coordinate-uncertainty schlicht2007-coordinate-uncertainty.txt, the project's staged copy 86e1fe6adf20bd32369c1df34c7d242245b51702 personal-copy neuroscience

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them mechanism Quotation withheld because this record is not cleared for redistribution. coordinate transformation uncertainty in reach-to-grasp Quotation withheld because this record is not cleared for redistribution. behavioural-experiment behavioural-experiment Quotation withheld because this record is not cleared for redistribution. mechanisms THE UNCERTAINTY IS MANIPULATED WITHOUT MOVING THE TARGET: the object stays in one place and the participant's EYE POSITION is varied instead, which changes the transformation between eye and head and so adds uncertainty to the remapped location while leaving the object alone Quotation withheld because this record is not cleared for redistribution. mechanisms THE LEVER IS A KNOWN PROPERTY OF THE SYSTEM RATHER THAN AN INTERVENTION: the authors exploit the fact that error in encoding eye position already varies with saccade magnitude and with eccentricity from forward view, so simply choosing where to look sets the uncertainty Quotation withheld because this record is not cleared for redistribution. mechanisms THE PREDICTION IS BUILT AS A CONDITIONAL WITH BOTH ANTECEDENTS NAMED: if the brain stores targets in eye-centred coordinates AND compensates for the effects of the uncertainty, then the grip aperture must vary with eye position EVEN WHEN THE TARGET CANNOT BE SEEN Quotation withheld because this record is not cleared for redistribution. mechanisms the target is deliberately NEVER MOVED across the workspace, and the reason is stated: so that any change in reaching behaviour must come from eye position and viewing eccentricity rather than from the kinematic demands of reaching somewhere else Quotation withheld because this record is not cleared for redistribution. mechanisms and its position was CHOSEN to maximise the very quantity under study - placed so that the widest possible range of eye positions away from the target was available, giving the greatest range of uncertainty Quotation withheld because this record is not cleared for redistribution. mechanisms ONE FIXATION POINT IS DROPPED PURELY TO KEEP THE TWO CONDITIONS COMPARABLE: the zero-degree fixation is excluded because the occluder would block both the target and that fixation letter, so the visual and occluded groups see the same set of fixations Quotation withheld because this record is not cleared for redistribution. mechanisms TWO DESIGNS ARE RUN WITH THE SAME NUMBER OF REPETITIONS PER FIXATION, and the trade-off between them is stated rather than left implicit: the full range captures the functional form of the response profile, the partial range buys statistical power in less time Quotation withheld because this record is not cleared for redistribution. mechanisms visual information is removed at DIFFERENT MOMENTS DURING the reach using liquid crystal shutter glasses, while separate occluders remove information about the hand and the target Quotation withheld because this record is not cleared for redistribution. mechanisms the read-out is justified by prior work before it is used: maximum grip aperture is known to scale with object size and to INCREASE when visual information is degraded Quotation withheld because this record is not cleared for redistribution. mechanisms the experimental logic is stated as an if-then over that read-out: if grip aperture changes with eye position when the target is OCCLUDED, that is taken to suggest the brain uses knowledge of the transformation uncertainty when planning a reach from a stored location Quotation withheld because this record is not cleared for redistribution. An attentional-load account of the occluded-condition effect cannot be excluded by the data, only argued against. what this limits: the target-uncertainty account of the occluded condition: IT MAY BE THAT HOLDING EYE POSITION AWAY FROM FORWARD VIEW CREATES AN ATTENTIONAL LOAD THAT AFFECTS GRASPING Quotation withheld because this record is not cleared for redistribution. The results are consistent with, but do not establish exclusive, eye-centred storage; multiple simultaneous reference frames remain possible. what this limits: any exclusive claim for eye-centred storage: OUR RESULTS DO NOT PRECLUDE THE POSSIBILITY THAT TARGET INFORMATION IS STORED IN MULTIPLE COORDINATE FRAMES Quotation withheld because this record is not cleared for redistribution. The visual fixation marks used in the task may themselves have induced the eye-centred storage strategy the study infers. what this limits: the eye-centred conclusion, which the apparatus may have produced: ANOTHER POSSIBILITY IS THAT VISUAL FIXATION MARKS PROMOTED AN EYECENTERED STORAGE STRATEGY Quotation withheld because this record is not cleared for redistribution. The model assumes large memory uncertainty and the data could not adjudicate a limited-memory alternative. what this limits: the large-memory-uncertainty assumption: WE COULD NOT REJECT A LIMITED MEMORY MODEL ON THE BASIS OF CROSS-TRIAL ANALYSES - ANY INFLUENCES OF FIXATIONS FROM PREVIOUS TRIALS WERE TOO SMALL TO BE RELIABLY MEASURED Quotation withheld because this record is not cleared for redistribution. The paper's own alternative explanation is that the apparatus induced the strategy the study infers: the visual fixation marks may have 'promoted an eye-centered storage strategy', being usable to maintain a representation of the body's configuration with respect to the apparatus. It is raised as a possibility and not settled, so the inference from behaviour to storage frame is conditional on the fixation marks not having supplied the frame. Quotation withheld because this record is not cleared for redistribution. a Bayesian model of location inference used to predict how grip aperture compensates for coordinate-transformation uncertainty Quotation withheld because this record is not cleared for redistribution. the whole experiment was re-run on a DIFFERENT GROUP with a visual occluder that showed the target but not the hand eliminates: that maximum grip aperture reflects something other than uncertainty about object LOCATION - the occluder holds target visibility constant while removing hand vision · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. a fully visual condition run alongside the uncertainty conditions eliminates: that grip aperture fails to track uncertainty at all - the visual condition establishes that the measure responds when it should · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. remapping remapping Quotation withheld because this record is not cleared for redistribution. reference frame reference frame Quotation withheld because this record is not cleared for redistribution. fixation marks fixation marks Quotation withheld because this record is not cleared for redistribution. saccade magnitude → eye position THE TWO CANNOT BE SEPARATED IN THIS STUDY - the DESIGN form of the negative relation / No edge type can express it: all eight assert that a relation HOLDS. A confounding statement bounds what the paper's own results can mean, and it lives where nothing downstream will find it. Two sources of the same uncertainty, inseparable because of where the subjects were asked to look. — about this quote: DAMAGED GLYPHS IN THIS QUOTE: (cid:1), (cid:5). These are raw PDF font glyph indices that leaked out in place of the characters they stand for - usually a mathematical operator. The quote is verbatim to the staged text and its anchor is sound; the STAGED TEXT is what is damaged. NOT repaired: the cid-to-character mapping is defined by the font embedded in that particular PDF, so guessing it would produce a clean and unverifiable quote. Repair needs the source PDF and is a re-staging job. Quotation withheld because this record is not cleared for redistribution. reliability - AS A PROPERTY OF THE STORAGE FORMAT, NOT OF THE MEASUREMENT: the same target information is more or less reliable according to which coordinate frame holds it, because each remapping between frames degrades the estimate Quotation withheld because this record is not cleared for redistribution. builds-on → Sober and Sabes (2005) Quotation withheld because this record is not cleared for redistribution. extends → neural and pointing evidence for eye-centred target storage (Batista et al. 1999; Pouget et al. 2002; Henriques et al. 1998; Crawford et al. 2004; Lewald and Ehrenstein 2000; Mergner et al. 2001) Quotation withheld because this record is not cleared for redistribution. extends → Lewald and Ehrenstein (2000) pointing data Quotation withheld because this record is not cleared for redistribution. remapping —causes→ coordinate transformation uncertainty remapping coordinate transformation uncertainty strength of the relation: 0.9 · note: EVERY CONVERSION BETWEEN REPRESENTATIONS COSTS ACCURACY, STATED FLATLY: '…by each transformation made…' And the system is said to respond by choosing its format accordingly - '…that minimize the impact…' (Sober and Sabes 2005). The format is not a neutral container: it is picked to minimise conversion loss. Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span defines coordinate transformation uncertainty; remapping is not named in it. Quotation withheld because this record is not cleared for redistribution. reference frame —causes→ coordinate transformation uncertainty reference frame coordinate transformation uncertainty strength of the relation: 0.9 · note: THE SAME TARGET IS MORE OR LESS RELIABLE DEPENDING ON WHICH FRAME IT IS STORED IN: '…depending on the reference frame used for storage…' The reliability is a property of the storage format rather than of the object measured, which is why the paper can infer the frame from behaviour at all. Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span says CTU creates reliability differences DEPENDING ON the reference frame; causes is loose. Quotation withheld because this record is not cleared for redistribution. the amount of compensation is predicted by a Bayesian eye-centered model Quotation withheld because this record is not cleared for redistribution. sensory information in different reference frames must be remapped into a common frame before integration Quotation withheld because this record is not cleared for redistribution. eye position eye position Quotation withheld because this record is not cleared for redistribution. maximum grip aperture maximum grip aperture about this quote: THE QUOTE STOPS WHERE THE EXTRACTED TEXT GOES OUT OF ORDER: after its last word the extraction gives 'visual' and then 'is occluded. Moreover, …', but the words between them ('information and for changes in CTU…') appear further on, so the sentence cannot be completed from this copy. Quotation withheld because this record is not cleared for redistribution. coordinate transformation uncertainty (CTU) coordinate transformation uncertainty (CTU) Quotation withheld because this record is not cleared for redistribution. Bayesian Bayesian Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1152/jn.00160.2007.