Sensorimotor control
While understanding the processes that lead to our conscious perception of the world is important and interesting, perhaps more fundamental to human behavior in the natural world are the processes by which the brain uses visual information to guide motor behavior. These processes occur "under the radar" of consciousness and in some cases appear to be distinct from those that determine our conscious percepts – neuropsychological dissociations between vision for perception and vision for action abound in the literature.
We use naturalistic visuo-motor tasks in virtual reality systems to study how humans use visual information to guide motor behavior. Rather than asking subjects what they see, we track their hand movements during visually guided tasks to make inferences about how the brain is using visual information to guide the hand. We have, for example, shown that humans automatically and continuously use visual feedback to guide reaching movements despite any conscious awareness of doing so. For example, we make automatic online corrections to fast hand movements in response to artificially induced visual error signals despite being unaware of those signals.
We work to understand the computations underlying this behavior by comparing human performance to that optimal control models that use visuo-motor strategies optimized to perform efficiently under the constraints of image and motor noise.
We are currently extending this work to studying visuomotor learning and how the brain learns
visuomotor tasks.
- Kwon, O. S. and Knill, D. C. (2013) The brain uses adaptive internal models of scene statistics for sensorimotor estimation and planning, Proceedings of the National Academy of Sciences, 110(11): E1064-73. PDF Supplement
- Issen, L. A. and Knill, D. C. (2012) Decoupling eye and hand movement control: Visual short-term memory influences reach planning more than saccade planning, Journal of Vision, 12(1):3; 1-12. PDF
- Michel, M., Brouwer, A. Jacobs, R. and Knill, D. C. (2011) Optimality Principles Apply to a Broad Range of Information Integration Problems in Perception and Action, in (Trommershauser, J. Kording, K., and Landy, M. S. eds.) Sensory Cue Integration, Osford Univ. Press, Oxford, England.
- Hu, B. and Knill, D. C. (2011) Binocular and monocular depth cues in online feedback control of 3-D pointing movements, Journal of Vision, 7(11)23: 1 – 13.
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Knill, D. C., Bondada, A. and Chhabra, Manu (2011) Flexible, task-dependent use of sensory feedback to control hand movements, Journal of Neuroscience, 31(4): 1219-1237.
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Sims, C. R., Jacobs, R. A. and Knill, D. C. (2011) Adaptive allocation of vision under competing task demands, The Journal of Neuroscience, 31(3): 928-943.
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Greenwald, H. and Knill, D. C. (2009) Cue Integration Outside Central Fixation:
A Study of Grasping in Depth, Journal of Vision, Vol. 9, No. 2, 1 - 16.
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Brouwer, A. and Knill, D. C. (2009) Humans use visual and remembered information about object location to plan pointing movements Journal of Vision, 9 (1), 1 – 19.
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Greenwald, H. and Knill, D. C. (2008) A Comparison of Visuomotor Cue Integration Strategies for Object Placement and Prehension, Visual Neuroscience, Aug., 1 - 10.
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Seydell, A., McCann, B. C., Trommershauser, J. and Knill, D. C. (2008) Learning stochastic reward distributions in a speeded pointing task, Journal of Neuroscience, 28: 4356-4367.
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Brouwer, A. and Knill, D. C. (2007) The role of memory in visually guided reaching, Journal of Vision, 7 (5), 1-12.
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Saunders, J and Knill, D. C. (2005) Humans use continuous visual feedback from the hand to control both the direction and distance of pointing movements, Exp. Brain Research, 162 (4), 458-73.
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Greenwald, H., Knill, D. C. and Saunders, J. (2005) Integrating depth cues for visuomotor control: A matter of time, Vision Research, 45 (15), 1975 - 1989.
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Knill, D. C. (2005) Reaching for visual cues to depth: The brain combines depth cues differently for motor control and perception, Journal of Vision, 5 (2), 103-115.
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Saunders, J and Knill, D. C. (2004) Visual feedback control of hand movements, J. of Neuroscience, 24 (13), 3223-3234.
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Knill, D. C. and Kersten, D. (2004), Visuomotor sensitivity to visual information about surface orientation, J. of Neurophysiology. 91 (3): 1350-1366.
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Saunders, J and Knill, D. C. (2003) Humans use continuous feedback from the hand to control reaching movements, Exp. Brain Research, 152 (3), 341-52.
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