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Updated: Aug 14, 2026
09:49
Methods to Explore the Influence of Top-down Visual Processes on Motor Behavior
Published on: April 16, 2014
Unawareness of visual and sensorimotor defects: a hypothesis
1Neurology Services, Spaulding Rehabilitation Hospital, Boston, MA 02114.
Brain and Cognition
|July 1, 1990
Summary
Unawareness of sensory loss, like blindness or phantom limbs, arises because the brain must infer deficits. This perceptual completion explains why some neurological conditions go unnoticed.
Area of Science:
- Neuroscience
- Cognitive Science
- Sensory Perception
Background:
- Sensory pathway interruption does not immediately signal a specific deficit.
- Self-observation and inference are required to discover sensory loss.
- Major functional impairments, like total blindness, are easier to detect.
Observation:
- Unawareness of hemianopsia (visual field loss) is common due to compensatory mechanisms.
- Insensate fields can generate false perceptions (suggested percepts).
- Sensory input from intact areas can lead to perceptual completion of missing information.
Findings:
- Perceptual completion explains unawareness in hemianopsia and hemiplegia.
- Phantom limb sensation results from perceptual completion without cognitive impairment.
- Unawareness of hemiplegia typically involves additional cognitive deficits.
Implications:
- Understanding perceptual completion offers insights into sensory processing and awareness.
- This theory may explain phenomena like phantom limb sensation and anosognosia.
- Parallel-distributed processing in sensory systems and cortex could underlie these effects.
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