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Sensory transformations and the use of multiple reference frames for reach planning.

McGuire LM, Sabes PN - Nat. Neurosci. (2009)

Bottom Line: This model incorporates the patterns of gaze-dependent errors that we found in our human psychophysics experiment when the sensory signals available for reach planning were varied.These results challenge the widely held ideas that error patterns directly reflect the reference frame of the underlying neural representation and that it is preferable to use a single common reference frame for movement planning.Furthermore, the presence of multiple reference frames allows for optimal use of available sensory information and explains task-dependent reweighting of sensory signals.

View Article: PubMed Central - PubMed

Affiliation: W. M. Keck Center for Integrative Neuroscience, Department of Physiology, and the Neuroscience Graduate Program, University of California, San Francisco, California, USA.

ABSTRACT
The sensory signals that drive movement planning arrive in a variety of 'reference frames', and integrating or comparing them requires sensory transformations. We propose a model in which the statistical properties of sensory signals and their transformations determine how these signals are used. This model incorporates the patterns of gaze-dependent errors that we found in our human psychophysics experiment when the sensory signals available for reach planning were varied. These results challenge the widely held ideas that error patterns directly reflect the reference frame of the underlying neural representation and that it is preferable to use a single common reference frame for movement planning. We found that gaze-dependent error patterns, often cited as evidence for retinotopic reach planning, can be explained by a transformation bias and are not exclusively linked to retinotopic representations. Furthermore, the presence of multiple reference frames allows for optimal use of available sensory information and explains task-dependent reweighting of sensory signals.

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Related in: MedlinePlus

Reach errors at the center target for an example subject for all trial types. Lines indicate mean reach error for each gaze-position, ellipses represent standard deviation, + fixation points, • reach targets. The origin (not shown) is located directly below midpoint of the eyes.
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Figure 1: Reach errors at the center target for an example subject for all trial types. Lines indicate mean reach error for each gaze-position, ellipses represent standard deviation, + fixation points, • reach targets. The origin (not shown) is located directly below midpoint of the eyes.

Mentions: A comparison of reach endpoints for an example subject at the midline target illustrates how reach errors depend on the available sensory signals (Fig. 1). The mean error changed markedly as a function of gaze location, and these gaze-dependent effects differed across trial types. During VIS and VIS+PROP trials (Fig. 1a–d), reach endpoints were biased away from the gaze location (the retinal eccentricity effect), and the magnitude of the effect decreased with increasing sensory information (Fig. 1a vs. 1b–d). In PROP trials, a small bias toward gaze location was observed instead (Fig. 1e,f). These patterns were consistent across targets (Supplemental Section 1.1 and Fig. S2, online). In addition to these gaze-dependent effects, there was a gaze-independent bias in reaching that could differ across targets and trial types. While there was a trend toward overshooting the target, the pattern of this bias, measured across targets and trial types in a separate gaze-free trial condition, was idiosyncratic from subject to subject (Supplemental Section 1.2 and Fig. S3, online), making these patterns difficult to interpret. We therefore focused on the consistent gaze-dependent effects.


Sensory transformations and the use of multiple reference frames for reach planning.

McGuire LM, Sabes PN - Nat. Neurosci. (2009)

Reach errors at the center target for an example subject for all trial types. Lines indicate mean reach error for each gaze-position, ellipses represent standard deviation, + fixation points, • reach targets. The origin (not shown) is located directly below midpoint of the eyes.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2749235&req=5

Figure 1: Reach errors at the center target for an example subject for all trial types. Lines indicate mean reach error for each gaze-position, ellipses represent standard deviation, + fixation points, • reach targets. The origin (not shown) is located directly below midpoint of the eyes.
Mentions: A comparison of reach endpoints for an example subject at the midline target illustrates how reach errors depend on the available sensory signals (Fig. 1). The mean error changed markedly as a function of gaze location, and these gaze-dependent effects differed across trial types. During VIS and VIS+PROP trials (Fig. 1a–d), reach endpoints were biased away from the gaze location (the retinal eccentricity effect), and the magnitude of the effect decreased with increasing sensory information (Fig. 1a vs. 1b–d). In PROP trials, a small bias toward gaze location was observed instead (Fig. 1e,f). These patterns were consistent across targets (Supplemental Section 1.1 and Fig. S2, online). In addition to these gaze-dependent effects, there was a gaze-independent bias in reaching that could differ across targets and trial types. While there was a trend toward overshooting the target, the pattern of this bias, measured across targets and trial types in a separate gaze-free trial condition, was idiosyncratic from subject to subject (Supplemental Section 1.2 and Fig. S3, online), making these patterns difficult to interpret. We therefore focused on the consistent gaze-dependent effects.

Bottom Line: This model incorporates the patterns of gaze-dependent errors that we found in our human psychophysics experiment when the sensory signals available for reach planning were varied.These results challenge the widely held ideas that error patterns directly reflect the reference frame of the underlying neural representation and that it is preferable to use a single common reference frame for movement planning.Furthermore, the presence of multiple reference frames allows for optimal use of available sensory information and explains task-dependent reweighting of sensory signals.

View Article: PubMed Central - PubMed

Affiliation: W. M. Keck Center for Integrative Neuroscience, Department of Physiology, and the Neuroscience Graduate Program, University of California, San Francisco, California, USA.

ABSTRACT
The sensory signals that drive movement planning arrive in a variety of 'reference frames', and integrating or comparing them requires sensory transformations. We propose a model in which the statistical properties of sensory signals and their transformations determine how these signals are used. This model incorporates the patterns of gaze-dependent errors that we found in our human psychophysics experiment when the sensory signals available for reach planning were varied. These results challenge the widely held ideas that error patterns directly reflect the reference frame of the underlying neural representation and that it is preferable to use a single common reference frame for movement planning. We found that gaze-dependent error patterns, often cited as evidence for retinotopic reach planning, can be explained by a transformation bias and are not exclusively linked to retinotopic representations. Furthermore, the presence of multiple reference frames allows for optimal use of available sensory information and explains task-dependent reweighting of sensory signals.

Show MeSH
Related in: MedlinePlus