Unit 9 - The Acting Brain Flashcards
For a very basic cognitive framework for understanding movement and action, what would be the highest level? How about the lowest level? What can action thus be seen as?
Action planning based on goals and intentions of individual
Perceptual and motor systems that interface with the external world
An outcome of all of these processes working together
What are the two primary things that action combines? Given this, is action the same as movement?
Needs of the person and the current environmental reality
No
What must crucially be taken into account when looking to interact with objects in the environment?
The position of the sensory receptors (that tell one information about the object) relative to the object
What is the degrees of freedom problem?
The fact that there are a potentially infinite number of motor solutions for acting on an object
What are motor programs? To what level of specificity do these programs code?
Stored routines specify motor parameters of an action (e.g., relative timing of strokes).
They address general aspects of movement rather than the specific means (e.g., joints and muscles).
What is somatosensation? What does it include?
A cluster of perceptual processes that relate to the skin and body
Touch, pain, thermal sensation, and limb position
What is proprioception?
Knowledge of the position of the limbs in space
What is sensorimotor transformation?
Linking together the perceptual knowledge of objects in space with knowledge of one’s body to enable objects to be acted on
Where do action and movement mainly take place? What happens to the functions of regions in the frontal lobes as one moves from the posterior to the anterior?
Frontal lobes
Function becomes decreasingly specific to movement and action
What is the homunculus problem? What is the real “man” within us?
The problem of explaining volitional acts without assuming a cognitive process that is itself volitional (“a man within a man”)
The firing of neurons
What is the primary function of the premotor regions? What are the two areas of the premotor cortex important for?
Preparing actions
The lateral area important for linking action with visual objects in the environment
The medial area of the premotor cortex (SMA) deals with self-generated actions
Do neurons fire according to the spatial location of the endpoint of a movement, the direction of the movement, or both?
Neurons only fire according to the direction of the movement
What can electrical stimulation of the FEF cause? What does this imply about action relative to cognition?
Enhanced activity within primary visual cortex (in presence of visual stimuli) and in higher visual regions (even in absence of visual stimuli)
That it can influence it, and is not simply an endpoint of cognition
What is the function of the primary motor cortex? What are the functions of most other frontal regions? What is meant by the primary motor cortex being somatotopically organised? What do the left and right hemispheres concern themselves with?
The execution of voluntary movements of the body
Planning, irrespective of action execution
That different regions of it represent different regions of the body
Right hemisphere with movements of left side of body, and vice versa
What is a population vector? What can it be used for?
The sum of preferred tunings of neurons multiplied by their firing rates?
Calculate the direction of a desired movement
What is hemiplegia?
Damage to one side of the primary motor cortex resulting in a failure to voluntarily move the other side of the body
Which of the SMA and lateral premotor region is more important for internally-generated actions? How about for producing movements based on external contingencies?
SMA for internal, lateral for external
What is the supplementary motor area (SMA)? What action sequences does it work with in particular?
Medial area of the premotor cortex
Deals with well-learned actions
Action sequences that do not place strong demands on monitoring the environment
Which region is voluntary movement of the eyes determined by?
Frontal Eye Fields (FEFs)
Where do the prefrontal regions of the brain lie relative to the premotor regions? What are they involved in? What is their role in relation to actions? What does damage to the prefrontal region not cause and what does it cause?
Anteriorly
Higher cognition
Mediate the selection of actions and maintain the goals of action
Does not impair movement or execution of actions. Instead, the actions become poorly organised and do not reflect the goals and intentions of the individual.
In which lobe are the primary motor cortex and premotor cortex located?
Frontal lobe
What does the Supervisory Attentional System (SAS) explain? What is its key distinction?
The control of cognition, generally
Actions that are performed automatically (with minimal awareness)
vs
Actions that require attention and some form of online control
What is perseveration?
Repeating an action that has already been performed and is no longer relevant
What is utilisation behaviour?
Impulsively acting on irrelevant objects in the environment
What is a schema? What can have their own schemas, and what would be their schema?
An organised set of stored information, such as familiar action routines
Specific objects, e.g. a hammer, and its schema would consist of motor programs
What is contention scheduling? What are two crucial inputs into this system?
The mechanism that selects one particular schema to be enacted from a host of competing schemas
Information about the needs/wants of the person
Information about the environmental reality
What is meant by a sense of agency?
The subjective feeling that voluntary actions are owned and controlled by the actor
What is a study relevant to this sense of agency? What does this suggest? What does this say about free will?
The motor cortex generates a readiness potential before conscious decision.
The brain commits to action unconsciously before conscious intention.
Free will is an illusion.
What is a forward model? Example
A representation of the motor command (called an efference copy) being used to predict the sensory consequences of an action
Tickling yourself
What is imitation? What does it involve?
The ability to reproduce the behaviour of another through observation
Computing the goals and intentions of the actor and then reproducing the actions
What is intentional binding? What is this a consequence of?
The phenomenon that voluntary actions and their sensory consequences appear closer together in time than they really are
Forward models
What is joint action?
A form of social interaction whereby two or more individuals coordinate their actions
What is mimicry?
A reproduction of an action via sensorimotor transformation that does not make any inferences about the goals and intentions of the actor
Do humans tend to reproduce the actions of others through mimicry or imitation?
Imitation
What are the two routes of visual processing?
Ventral stream (from occipital to temporal) for identification (what)
Dorsal stream (from occipital to parietal) for action (how)
What is a mirror-neuron? When do they not respond? What does this suggest?
A neuron that responds to goal-directed actions performed by oneself or by others
For mimicked actions in the absence of an object, and if the object moves robotically without an external agent
That the purposeful nature of the action is what is critical to its firing
What takes place when the ventral stream is damaged in terms of actions? For example?
A dissociation between visual perception and visual control of action
Difficulties in reporting the needed orientation to match letters to an opening in a letter box
What takes place when the dorsal stream is damaged in terms of actions?
Difficulties acting towards objects in space, like mis reaching
What is optic ataxia?
An inability to use vision to accurately guide action, without basic deficits in visual discrimination or voluntary movement
What is the parietal reach region? Which region does it, crucially, interact with? What do these two regions do together?
A part of the occipito-parietal cortex that responds, in particular, to reaching movements
Lateral Intraparietal area, which codes the distance and direction needed to move the eyes from the current location toa visual stimulus in its receptive field
Planning actions and predicting their sensory consequences
What is the anterior intraparietal area (AIP)? What two processes is this area involved in?
A part of the intraparietal sulcus that responds, in particular, to manipulable shapes or 3D objects (from vision or touch)
Grasping, Object Recognition
What is the ventral intraparietal area (VIP)?
A part of the intraparietal sulcus that responds to objects close to the body and in body-centred (as opposed to gaze-centred) coordinates
What is a phantom limb?
The feeling that an amputated limb is still present
What is a tool? What are the four levels at which they are represented?
An object that affords certain actions for specific goals
A visual representation of the shape of the object (visual ventral stream)
Semantic representation of the object (medial, anterior temporal lobes)
Volumetric representation with both visual and motoric components
Motor-based component, storing conventional gestures associated with tool
What are affordances?
Structural properties of objects implying certain usages
What is ideomotor apraxia?
An inability to produce appropriate gestures given an object, word or command
What are subcortical structures important for in action?
The preparation and execution of actions, specifically the setting of parameters of movement like force and duration
What is the spinal cord? What does it control?
A connection between the brain and muscles
Reflexive movements (reflexes) to prevent injury in situations where one needs to act fast
What are the two main types of cortical-subcortical loops involved in the generation of movement?
The cerebellar loop and the basal ganglia loop
What is meant by hypokinetic?
A reduction in movement
What do each of the inner loops deal with?
Prefrontal loop - control of cognition
Oculomotor loop - control of eye movements
Limbic loop - reward based learning
Motor loop (of relevance) - initiation and execution of internally generated movements, sequencing of actions, and procedural learning
What is the cerebellar loop involved in? What can damage to the cerebellum cause?
The coordination of movement, ensuring that the desired movement occurs accurately and at the desired time
Inability to use information about the progress of movement to update the initiated motor program
What does the basal ganglia loop consist of?
Five different loops, being (one missing):
The prefrontal loop, the oculomotor loop, the limbic loop, the motor loop
What are the hypokinetic disorders of the basal ganglia?
Parkinson’s
What is Parkinson’s disease? The loss of what kind of cells causes it? Does it affect all types of movement equally? Which types of actions are more impaired than the others? Which of the two pathways has its output decreased and which has its output increased: the indirect pathway (brakes) or the direct pathway (the accelerator)?
A disease associated with the basal ganglia and characterised by a lack of self-initiated movement
Dopaminergic cells
No
Self-initiated actions vs actions triggered by their environment
The indirect pathway has increased output, while the direct pathway has decreased output
What is meant by hyperkinetic?
Increase in movement
What are the hyperkinetic disorders of the basal ganglia?
Huntington’s, and Tourette’s
What is Huntington’s disease? Which type of pathway has its output increased and which decreased?
A genetic disorder affecting the basal ganglia and associated with excessive movement
Indirect pathway has lower output, direct pathway higher
What is Tourette’s syndrome? Which part of the brain is activated more for patients?
A neuropsychiatric disorder with an onset in childhood characterised by the presence of motor and/or vocal tics
The prefrontal cortex
