Eye–hand coordination
Encyclopedia
Eye–hand coordination is the coordinated control of eye movement with hand movement, and the processing of visual input
to guide reaching and grasping along with the use of proprioception of the hands
to guide the eyes. In simple terms, eye-hand coordination involves the coordinated vision and hand movement to execute a task. It has been studied in activities as diverse as tea making, the movement of solid objects such as wooden blocks, sporting performance, music reading
, online first-person computer gaming, and copy-typing. It is a way of performing everyday tasks and in its absence most people would be unable to carry out even the simplest of actions such as picking up a book from a table or playing a video game. While it is recognized by the term hand–eye coordination, without exception medical references assign it the title of eye–hand coordination.
toward the hand without vision, using spatial information from hand proprioception.
For sequential tasks, it has been observed that eye gaze movements occur during important kinematic events like changing the direction of a movement, or when passing perceived landmarks. This is related to the task search oriented nature of the eyes and their relation to movement planning of the hands, and the errors between motor signal output and consequences perceived by the eyes and other senses which can be used for corrective movements. Furthermore, the eyes have been shown to have a tendency to ‘refixate’ upon a target in order to refresh the memory of its shape, or to update for changes in its shape or geometry. This has also been shown to be true in drawing tasks with relating visual input and converting it into hand movements to produce a copy of what was perceived. In high accuracy tasks, studies have shown that when acting upon greater amounts of visual stimuli, the time it takes to plan and execute movements, increases linearly as per Fitts’s Law.
, with only minor errors related to the internal knowledge of limb position. It has been shown the proprioception of limbs, both active and passive movements of the limbs are result in eye saccades overshoots when the hands are being used to guide eye movements. These overshoots have been determined to result from the control of eye saccades rather than previous movements of the hands in experiments. As a result, limb based proprioception has been determined to be capable of being transformed into ocular motor coordinates to guide eye saccades, which allows for the guidance of the saccades by the hands and feet.
A more specific area, the parieto
occipital junction
, is believed to be involved in the transformation of peripheral visual input for reaching with the hands, as found via fMRI. This region in particular has been shown to have subdivisions for reach, grasp, and saccades. In additional to the parieto occipital junction, the posterior parietal cortex is believed to play an important role in relating proprioception and the transformation of motor sensory input to plan and control movement with regards to visual input.
Many of these areas, in addition to controlling saccades or reach, also show eye position signals that are required for transforming visual signals into motor commands. In addition, some of the areas involved in reach, like the medial intraparietal cortex, show a gaze-centered remapping of responses during eye movements in both monkeys and humans. However, when single neurons are recorded in these areas, the reach areas often show some saccade-related responses and the saccade areas often show some reach related responses. This may aid in eye–hand coordination or hint at the ability of cells to wire together as they’re used more frequently.
is characterized by a complete lack of eye-hand coordination and has been demonstrated to occur in isolation to Optic Ataxia. Generally characterized as a paralysis of eye saccades and inability to scan, this condition is most commonly caused by strokes, tumors, and Alzheimer’s disease.
have been observed to show the same impairments as normal aging, only to a more extreme degree, in addition to a loss of control of motor functions as per normal symptoms of the disease. This results from the general degeneration of neural tissue due to aging, compounded by the disruption of neurotransmitters caused by Parkinson’s resulting in slower movements than normal adults of a similar age. The ability to plan and learn from experience has been shown to allow adults with Parkinson’s to improvement times, but only under conditions where they are using medications to combat the effects of Parkinson’s.
Visual perception
Visual perception is the ability to interpret information and surroundings from the effects of visible light reaching the eye. The resulting perception is also known as eyesight, sight, or vision...
to guide reaching and grasping along with the use of proprioception of the hands
Proprioception
Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...
to guide the eyes. In simple terms, eye-hand coordination involves the coordinated vision and hand movement to execute a task. It has been studied in activities as diverse as tea making, the movement of solid objects such as wooden blocks, sporting performance, music reading
Musical notation
Music notation or musical notation is any system that represents aurally perceived music, through the use of written symbols.-History:...
, online first-person computer gaming, and copy-typing. It is a way of performing everyday tasks and in its absence most people would be unable to carry out even the simplest of actions such as picking up a book from a table or playing a video game. While it is recognized by the term hand–eye coordination, without exception medical references assign it the title of eye–hand coordination.
Behavior and kinematics
Neuroscientists have extensively researched human gaze behavior, with studies noting that the use of the gaze is very task-specific, but that humans typically exhibit proactive control over movements in order to guide movements. Usually, the eyes fixate upon a target before the hands are used to engage in a movement, indicating that the eyes are used to provide spatial information for the hands. Furthermore, the duration that the eyes appear to be locked onto a goal for a hand movement varies, with the eyes sometimes remaining fixated until a task is completed. Other times, the eyes seem to scout ahead toward other objects of interest before the hand even grasps and manipulates the object. Conversely, humans have been shown to be able to aim eye movementsSaccade
A saccade is a fast movement of an eye, head or other part of an animal's body or device. It can also be a fast shift in frequency of an emitted signal or other quick change. Saccades are quick, simultaneous movements of both eyes in the same direction...
toward the hand without vision, using spatial information from hand proprioception.
Eye-guided hand movements
The more dominant behavior in humans, studies have shown that when eyes and hands are used for core exercises, the eyes generally direct the movement of the hands to targets. Furthermore, the eyes provide initial information of the object, including its size, shape, and possibly grasping sites which are used to determine the force needed to be exerted by the fingertips for engaging in a given task. For shorter tasks, the eyes often shift onto another task in order to provide additional input for planning further movements. However, for more precise movements or longer duration movements, continued visual input is used to adjust for errors in movement and to create more precise movements.For sequential tasks, it has been observed that eye gaze movements occur during important kinematic events like changing the direction of a movement, or when passing perceived landmarks. This is related to the task search oriented nature of the eyes and their relation to movement planning of the hands, and the errors between motor signal output and consequences perceived by the eyes and other senses which can be used for corrective movements. Furthermore, the eyes have been shown to have a tendency to ‘refixate’ upon a target in order to refresh the memory of its shape, or to update for changes in its shape or geometry. This has also been shown to be true in drawing tasks with relating visual input and converting it into hand movements to produce a copy of what was perceived. In high accuracy tasks, studies have shown that when acting upon greater amounts of visual stimuli, the time it takes to plan and execute movements, increases linearly as per Fitts’s Law.
Hand-guided saccades
Humans have been demonstrated to be able to aim eye movements toward the hand without vision, using the sense of proprioceptionProprioception
Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...
, with only minor errors related to the internal knowledge of limb position. It has been shown the proprioception of limbs, both active and passive movements of the limbs are result in eye saccades overshoots when the hands are being used to guide eye movements. These overshoots have been determined to result from the control of eye saccades rather than previous movements of the hands in experiments. As a result, limb based proprioception has been determined to be capable of being transformed into ocular motor coordinates to guide eye saccades, which allows for the guidance of the saccades by the hands and feet.
Neural mechanisms
The neural control of eye–hand coordination is complex because it involves every part of the central nervous system involved in vision, eye movements, touch, and hand control. This includes the eyes themselves, the cerebral cortex, subcortical structures (such as the cerebellum, basal ganglia, and brain stem), the spinal cord, and the peripheral nervous system. Some other areas involved in eye–hand coordination that have been studied most intensely are the frontal and parietal cortex areas for the control of eye saccades and hand reach control. Both of these areas are believed to play a key role in eye-hand coordination and the planning of movements during tasks.A more specific area, the parieto
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
occipital junction
Occipital lobe
The occipital lobe is the visual processing center of the mammalian brain containing most of the anatomical region of the visual cortex. The primary visual cortex is Brodmann area 17, commonly called V1...
, is believed to be involved in the transformation of peripheral visual input for reaching with the hands, as found via fMRI. This region in particular has been shown to have subdivisions for reach, grasp, and saccades. In additional to the parieto occipital junction, the posterior parietal cortex is believed to play an important role in relating proprioception and the transformation of motor sensory input to plan and control movement with regards to visual input.
Many of these areas, in addition to controlling saccades or reach, also show eye position signals that are required for transforming visual signals into motor commands. In addition, some of the areas involved in reach, like the medial intraparietal cortex, show a gaze-centered remapping of responses during eye movements in both monkeys and humans. However, when single neurons are recorded in these areas, the reach areas often show some saccade-related responses and the saccade areas often show some reach related responses. This may aid in eye–hand coordination or hint at the ability of cells to wire together as they’re used more frequently.
Clinical syndromes
Numerous disorders, diseases, and impairments have been found to result in disruption to the coordination of the eyes and hands, owing to damage to the brain itself, degeneration of the brain due to disease or aging, or an apparent inability to coordinate senses completely.Aging
Impairments to eye-hand coordination have been shown to occur in older adults, especially during high velocity and precise movements. This has been attributed to the general degeneration of the brain’s cortex, resulting in a loss of the ability to compute visual inputs and relate them to hand movements. However, while older adults tend to take more time for these sorts of tasks, they are still able to remain just as accurate as younger adults, but only if the additional time is taken.Bálint's syndrome
Bálint's syndromeBalint's syndrome
Bálint's syndrome is an uncommon and incompletely understood triad of severe neuropsychological impairments: inability to perceive the visual field as a whole , difficulty in fixating the eyes , and inability to move the hand to a specific object by using vision...
is characterized by a complete lack of eye-hand coordination and has been demonstrated to occur in isolation to Optic Ataxia. Generally characterized as a paralysis of eye saccades and inability to scan, this condition is most commonly caused by strokes, tumors, and Alzheimer’s disease.
Optic apraxia
Optic apraxia is a condition that results from a total inability of a person to coordinate eye and hand movements. Although similar to optic ataxia, its effects are more severe and may not necessarily come from damage to the brain, but genetic defects or degeneration of tissue.Optic ataxia
Optic ataxia is a clinical problem associated with damage to the occipital–parietal cortex in humans, resulting in a lack of coordination between the eyes and hand. Optic ataxia has been often considered to be a high-level impairment of eye–hand coordination resulting from a cascade of failures in the sensory to motor transformations in the posterior parietal cortex. Optic ataxia has been often confused with Balint’s syndrome, but recent research has shown that optic ataxia can occur independently of Balint’s syndrome. Optic ataxia patients usually have troubles reaching toward visual objects on the side of the world opposite to the side of brain damage. Often these problems are relative to current gaze direction, and appear to be remapped along with changes in gaze direction. Some patients with damage to the parietal cortex show "magnetic reaching": a problem in which reaches seem drawn toward the direction of gaze, even when it is deviated from the desired object of grasp.Parkinson’s disease
Adults with Parkinson's diseaseParkinson's disease
Parkinson's disease is a degenerative disorder of the central nervous system...
have been observed to show the same impairments as normal aging, only to a more extreme degree, in addition to a loss of control of motor functions as per normal symptoms of the disease. This results from the general degeneration of neural tissue due to aging, compounded by the disruption of neurotransmitters caused by Parkinson’s resulting in slower movements than normal adults of a similar age. The ability to plan and learn from experience has been shown to allow adults with Parkinson’s to improvement times, but only under conditions where they are using medications to combat the effects of Parkinson’s.
See also
- KinematicsKinematicsKinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....
- Motor controlMotor skillA motor skill is a learned sequence of movements that combine to produce a smooth, efficient action in order to master a particular task. The development of motor skill occurs in the motor cortex, the region of the cerebral cortex that controls voluntary muscle groups.- Development of motor skills...
- NeuroplasticityNeuroplasticityNeuroplasticity is a non-specific neuroscience term referring to the ability of the brain and nervous system in all species to change structurally and functionally as a result of input from the environment. Plasticity occurs on a variety of levels, ranging from cellular changes involved in...
- Human sensesSenseSenses are physiological capacities of organisms that provide inputs for perception. The senses and their operation, classification, and theory are overlapping topics studied by a variety of fields, most notably neuroscience, cognitive psychology , and philosophy of perception...