User:AshleyHardy/Gain-field encoding

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Gain-field encoding is a hypothesis about the internal storage and processing of limb motion in the brain. Specific neurons have been reported to possess this ability to integrate prior knowledge of a motor task with an internal model to produce a desired motor output.[1] Gain-field encoding also involves sensory-motor coupling, which is the sensory and motor systems working concurrently to generate purposeful motor commands. One example is that visual input is represented in eye coordinates and must be transformed into motor coordinates that your muscles use to elicit an appropriate response. [2]


Overview[edit]

It has been suggested that the brain's motor system does not learn to control the dynamics of limbs by memorizing past experiences. Instead, it uses a form of dynamic adaptation in which the brain retains learned movements as a result of a change in the environment.[3]

Internal Model[edit]

Research has proposed that the brain learns an internal model by associating the state of the body with forces that arise that depend on the state of the limbs.[4] Equations of muscle force vectors

Motor Primitives[edit]

Research has shown that the brain learns arm movements by using a combination motor primitives. Equations


Sensorimotor Transformation[edit]

The sensorimotor system is able to translate information between different coordinate systems.

Eye-Centered Coordinates[edit]

Body-Part-Centered Coordinates[edit]

Research[edit]

Many studies have attempted to interpret how the motor system learns and adapts to a changing environment.

Models for Studying Motor Control[edit]

Motor skill learning and adaptation can be studied using various experimental techniques. Two standard approaches involve applying externally applied force fields to a subject during a reaching task or testing a subject's ability to visually rotate and interpret an image.[5]

Dynamic Adaptation[edit]

Applying perturbations to subjects during a motor task.

Visuomotor Adaptation[edit]

Rotating images and recording how a subject responds and if they can identify how much an image has been rotated.

Computational Mechanisms[edit]

Algorithms have been implemented in an attempt the model various aspects of the sensorimotor system.[6]

Nonlinearity[edit]

Nonstationarity[edit]

Delays[edit]

Redundancy[edit]

Uncertainty[edit]

Noise[edit]

Premotor Cortex[edit]

Dorsal Premotor Cortex[edit]

Ventral Premotor Cortex[edit]

Parietal Cortex[edit]

The parietal cortex plays a major role in the sensorimotor system.

Posterior Parietal Cortex[edit]

The idea of 'gain-field encoding' was first discovered in neurons of the posterior parietal cortex.

Lateral Intraparietal Cortex (LIP)[edit]

Involved in coding targets for saccadic eye movements.

Superior Colliculus[edit]

Future Directions[edit]

References[edit]

  1. ^ Yokoi, A (2011). "Gain field encoding of the kinematics of both arms in the internal model enables flexible bimanual action". The Journal Of Neuroscience: The Official Journal Of The Society For Neuroscience. 31 (47): 17058–17068.  Unknown parameter |coauthors= ignored (|author= suggested) (help)
  2. ^ Snyder, L.H. (2000). "Coordinate transformations for eye and arm movements in the brain". Current Opinion In Neurobiology. 10 (6): 747–754. 
  3. ^ Conditt, MA (1997). "The motor system does not learn the dynamics of the arm by rote memorization of past experience". Journal of Neurophysiology. 78 (1): 554-560.  Unknown parameter |month= ignored (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  4. ^ White, O. (2008). "Motor control: from joints to objects and back". Current Biology. 18 (12): 532-533.  Unknown parameter |coauthors= ignored (|author= suggested) (help)
  5. ^ Dayan, E. (2011). "L.G.". Neuron. 72 (3): 443-454.  Unknown parameter |coauthors= ignored (|author= suggested) (help)
  6. ^ Franklin, D.W. (2011). "Computational mechanisms of sensorimotor control". Neuron. 72 (3): 425-442.  Unknown parameter |coauthors= ignored (|author= suggested) (help)

External Links[edit]