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Sensorimotor transformation during eye movements to remembered visual targets
J W Gnadt1, R M Bracewell, R A Andersen
1Salk Institute, San Diego, CA 92138.
Vision Research
|January 1, 1991
Summary
Brain transformations for eye movements to remembered visual targets introduce spatial distortions. Errors, like upward hypermetria and downward hypometria, accumulate during memory delays, affecting accurate retinotopic registration.
Area of Science:
- Neuroscience
- Oculomotor research
- Visual processing
Background:
- Accurate eye movements require transforming visual information from retinotopic to oculomotor coordinates.
- Eye movements to remembered targets often exhibit spatial inaccuracies.
Purpose of the Study:
- To investigate the spatial distortions in eye movements directed towards remembered visual targets.
- To analyze the nature and timing of errors in the retinotopic-to-oculomotor transformation.
Main Methods:
- Analysis of eye movements made to visual targets.
- Observation of responses during memory-contingent delay periods.
- Quantification of spatial errors in saccadic eye movements.
Main Results:
- Eye movements to remembered targets showed significant spatial distortion.
- A consistent pattern of hypermetria for upward saccades and hypometria for downward movements was observed.
- The majority of spatial error accumulation occurred within the initial 800 milliseconds of memory delay.
Conclusions:
- The brain's transformation of visual to oculomotor coordinates is not perfectly accurate for remembered targets.
- Spatial coding and transformation theories must account for these observed constant and variable errors in eye movements.