The Acting Brain
This chapter provides an overview of research on the “acting brain” starting with higher-level planning of actions and free-will through to topics such as Parkinson’s disease, the role of the basal ganglia and tool use. The prefrontal cortex is involved in action selection (e.g., activated when contrasting open-ended versus instructed actions) but is not involved in movement per se. The primary motor cortex is responsible for the execution of all voluntary movements of the body. Visually guided actions involve the dorsal stream for vision which involves several regions of the parietal lobes that contain neurons with both visual and motor/body-centered receptive fields. The human brain contains a store of object-dependent actions that may reside in the left inferior parietal lobe and are impaired in ideomotor apraxia. Various route between the frontal cortex and basal ganglia are involved in the control of action (e.g., modifying the force) and a separate loop through the cerebellum updates ongoing action through sensory feedback.
Multiple Choice Questions
Flashcards
Problem whereby there are potentially an infinite number of motor solutions for acting on an object
Degrees of freedom problem
Stored routines that specify certain motor parameters of an action (e.g. the relative timing of strokes)
A cluster of perceptual processes that relate to the skin and body, and include touch, pain, thermal sensation, and limb position
Knowledge of the position of the limbs in space
Linking together perceptual knowledge of objects in space and knowledge of the position of one’s body to enable objects to be acted on
Sensorimotor transformation
The problem of explaining volitional acts without assuming a cognitive process that is itself volitional (" a man within a man" )
Part of the brain responsible for execution of voluntary movements of the body
The sum of the preferred tunings of neurons multiplied by their firing rates
Damage to one side of the primary motor cortex results in a failure to voluntarily move the other side of the body
The lateral area is important for linking action with visual objects in the environment; the medial area is known as the supplementary motor area and deals with self-generated actions
Region of premotor cortex that deals with well-learned actions, particularly action sequences that do not place strong demands on monitoring the environment
Supplementary motor area (SMA)
Repeating an action that has already been performed and is no longer relevant
Impulsively acting on irrelevant objects in the environment
An organized set of stored information (e.g. of familiar action routines)
The mechanism that selects one particular schema to be enacted from a host of competing schemas
A representation of the motor command (a so-called efference copy) is used to predict the sensory consequences of an action
The ability to reproduce the behavior of another through observation
A neuron that responds to goal-directed actions performed by oneself or by others
An inability to use vision to accurately guide action, without basic deficits in visual discrimination or voluntary movement per se
A part of occipito-parietal cortex that responds, in particular, to reaching movements
Parietal reach region (PRR)
A part of intra-parietal sulcus that responds, in particular, to manipulable shapes or 3D objects (from vision or touch)
Anterior intraparietal area (AIP)
A part of intra-parietal sulcus that responds to objects close to the body and in body-centered (as opposed to gaze-centered) coordinates
Ventral intraparietal area (VIP)
The feeling that an amputated limb is still present
An object that affords certain actions for specific goals
An inability to produce appropriate gestures given an object, word, or command (arising from brain damage)
Structural properties of objects imply certain usages
A disease associated with the basal ganglia and characterized by a lack of self-initiated movement
A genetic disorder affecting the basal ganglia and associated with excessive movement
