H10 the Acting Brain

• Action

  The outcome of a number of cognitive processes that translate the goals and intentions of an individual into a motor output
• Action

  A cognitive process
• Movement

  A physical act that is not necessarily cognitive (e.g. reflexes)
• There are potentially an infinite number of motor solutions for acting on an object (switch on light)
• Motor programs


  Stored routines that specify certain motor parameters of an action (e.g., the relative timing of strokes)
• Somatosensation


  A cluster of perceptual processes that relate to the skin and body, and include touch, pain, thermal sensation and limb position
• Proprioception


  Knowledge of the position of the limbs in space
• Sensorimotor transformation


  Linking together perceptual knowledge of objects in space and knowledge of the position of one's body to enable objects to be acted on
• Homunculus problem

  Trying to understand how we make decisions and have intentions without imagining a little person inside our brain controlling everything
• Frontal lobes

  • Planning actions, maintaining goals, executing actions
  • Parieto-frontal circuits link action with current environment
• Parietal lobes


  • Locating objects in space, sensorimotor transformation
• Temporal lobes


  • Object recognition, object knowledge
• Occipital lobes


  • Visual analysis of scene
• Subcortex (e.g. basal ganglia)

  • Modulate force and likelihood of action
• Subcortex (e.g. cerebellum)


  • Monitor action online
• Primary motor cortex (Brodmann's area 4, BA4)


  Responsible for execution of voluntary movements of the body
• Hemiplegia


  Damage to one side of the primary motor cortex results in a failure to voluntarily move the other side of the body
• Population vector

  The sum of the preferred tunings of neurons multiplied by their firing rates
• Premotor cortex

  • The lateral area is important for linking action with visual objects in the environment; the medial area is known as the supplementary motor area (SMA) and deals with self generated actions
• Supplementary motor area (SMA)

  Deals with well-learned actions, particularly action sequences that do not place strong demands on monitoring the environment
• Perseveration


  Repeating an action that has already been performed and is no longer relevant
• Utilization behavior

  Impulsively acting on irrelevant objects in the environment
• Schema


  An organized set of stored information (e.g., of familiar action routines)
• Sas-model


  The latter, but not the former, requires the intervention of an executive called the "supervisory attentional system" (SAS)
• Contention scheduling


  The mechanism that selects one particular schema to be enacted from a host of competing schemas
• Sense of agency


  The subjective feeling that voluntary actions are owned and controlled by the actor
• Forward model


  A representation of the motor command (a so-called efference copy) is used to predict the sensory consequences of an action
• Intentional binding


  The phenomenon that voluntary actions and their sensory consequences appear closer together in time than they really are
• Imitation

  The ability to reproduce the behavior of another through observation
• Mirror neuron


  A neuron that responds to goal-directed actions performed by oneself or by others
• Optic ataxia


  An inability to use vision to accurately guide action, without basic deficits in visual discrimination or voluntary movement per se
• Visual agnosia

  Impaired "what", spared "where"/"how"
• Parietal reach region (PRR)


  • A part of the occipitoparietal cortex that responds, in particular, to reaching movements
• Anterior intraparietal area (AIP)


  • A part of the intraparietal sulcus that responds, in particular, to manipulable shapes or 3D objects (from vision or touch)
• Ventral intraparietal area (VIP)


  • A part of the intraparietal sulcus that responds to objects close to the body and in body-centered (as opposed to gaze-centered) coordinates
• Phantom limb


  The feeling that an amputated limb is still present
• Tool

  An object that affords certain actions for specific goals
• Affordances

  Structural properties of objects imply certain usages
• Ideomotor apraxia


  An inability to produce appropriate gestures given an object, word or command
• Cerebellar loop


  • Involved in coordination of movement, may update the motor program online using visual feedback