Weeks 8-11 Perception of Action & Motor Control (ellen Poliakoff) Flashcards
What is crossmodal transfer?
Humans can seamlessly map visual representations of actions onto our motor systems to produce a copy of the action
Why is it thought that crossmodal transfer/perception-action mapping is innate?
Humans, unlike other species, are very good at this
What are two pieces of developmental evidence for perception-action mapping?
- Infants can imitate caregiver’s facial expressions, hand and mouth movements and head turns etc
- Babies must build up a representation of the visual image of the caregiver’s face/mouth and map this onto their own motor representation of the movement
At what age did Piaget state that imitation occurs?
No earlier than 1 year old
At what age did Meltzoff and Moore state that babies could imitate?
12-21 days old
What actions did Meltzoff and Moore find that babies imitate?
- Babies aged 12-21 days could imitate certain facial expressions
- Imitated specific acts such as lip protrusion and tongue (not whole body parts)
What is a study done by Oostenbroek et al that contradicted Metlzoff and Moores findings on infant imitation?
METHOD
- Conducted a longitudinal study on babies aged: 1, 3, 6 and 9 weeks old
- Provided a large number of alternative control model behaviours to the infants as well as the lip and tongue protrusion
RESULTS
- The tongue and lip protrusion occured better than chance in comparison to some control behaviours but not others
CONCLUSION
- Tongue protrusion may be elcicted by seeing faces and learning instead of direct imitation
- True imitation may emerge later (6-9 months)
What is the Active Intermodal Matching Model? Use the example of Neonates.
- Neonates recognise equivalences between body transformations they see and those of their own body that they ‘feel’ themselves make and learn to match the two
- Baby’s emotional expressions induce adults to produce similar expressions, which in turn provides the infants with a visual input to match the motor output
What are the different stages of the Active Intermodal Matching model?
- Visual perception of target/adult face acts
- Supramodal represntation of acts (equivalence detector)
- Proprioceptive information
- Infant motor acts
Give an example of the Active Intermodal Matching model (Baby example)
- Adult sticks out their tongue
- Baby sticks out their tongue
- Can feel the action through proprioceptive information
- Can then match their own tongue sticking out to that of the adults
What does the Active Intermodal Matching model claim about perception and action that disagrees with other theories?
- AIM suggests that perception and action have independent coding/representation and have a specialised module for imitation
- Other theories instead suggest common coding for perception and action and that imitation is part of a generalist process for motor control and learning
What is the Ideomotor theory? (Give Example)
- See someone moving something (finger)
- Have sensory representation (visual) on what this looks like
- This sensory input is linked with the motor representation (commands the muscles)
- This leads to the matching of the action (motor program)
What is an example of a study to show the ideomotor theory in action?
- Sensory information of someone frowning
- Motor representation is primed to frown
- Is then harder to smile because we a programmed to frown.
What is the Associative Sequence Learning theory?
- Emphasises learning through experience
- For example see consequence of own hand action
What is Rumiati and Tessari’s Dual Route Model of imitation?
- Incorporates aspects of the other models
- Has a semantic route if we have done an action before it is stored in a repetoire to be done again
- Has a visuomotor/direct route where new or meaningless actions require direct imitation to learn
What are the steps of the dual route model of imitation?
- Input action
- Visual analysis
- Long-term/semantic memory
or
- Short term/working memory
- Output action
Give an example of the semantic route of the dual model of imitation
- See someone waving
- Visually analyse and understand we have done this type of action before
- Wave in our own way back
What is an example of the visuomotor or direct route of the dual route model of imitation?
- Someone is teaching you a dance move
- We visually analyse the move and know we have not done it before
- Engage working and short term memory to learn and imitate the gesture
- Do the dance move
How were mirror neurons discovered?
The same premotor neurons were found to be active when the monkey performed an action and when they watched an action
What are the general properties of mirror neurons?
- Bimodal visuo-motor neurons (respond to both visual and motor stimuli)
- Discharge when individual perfors an action and when they observe the same aciton performed by another individual
What did Umilta et al find about mirror neurons and understanding?
Mirror neurons were active during observation of a partially hidden outcome (food hidden behind a screen)
They can predict an action outcome even in the abscence of complete visual information
What did Kohler et al find about audition and vision in terms of mirror neuron action?
- Audio-visual mirror neurons respond to the sound typically produced by the action
- When a monkey hears a nut being snapped and when the monkey is snapping the nut, the same component is active
- Also if can see the nut being snapped but cannot hear it, there is also activation
Where are mirror neurons found in monkeys?
Area F5 of premotor cortex and inferior parietal lobe
How are mirror neurons organised in the brain?
Somatotopically
How many types of neurons are found in monkeys F5?
3
What are the three types of neurons found in the monkeys F5?
- ‘Action observatoin related’ visuomotor neurons (mirror neurons)
- Motor neurons
- Canonical visuomotor neurons (object observation-related neurons)
What do canonical visuomotor neurons do?
Code associations with objects and specific actions such as a door handle being used to open a door
What is a behavioural study done into mirror neurons by Brass et al?
METHOD
- Participants observe an action being performed such as a finger moving up or down
- They are then told that when they see a yellow flash, they must press a button
RESULTS
- If observed finger movement was going down, they were faster at pressing the button compared to the incongruent action of the finger moving upwards
CONCLUSION
- Faster responses when compatibility between observed and executed movements
What is the lab analogue of mimicry as found in human behavioural studies called?
Automatic imitation
What is a study done by Buccino into human mirror neuron brain imaging?
METHOD
- Participants watched videos of people executing different movements
RESULTS
- Areas active in the premotor and parietal cortex of participants brain corresponded to obervations of actoins of different body parts
What did a meta-analysis by Hardwick et al onto the overlapping of perception and action in the brain discover?
METHOD
- Conducted a meta-analysis across different studies where brain activation was measured
RESULTS
- Found a prefrontal and parietal overlap in brain activity between action observation, movement execution and motor imagery (imagined movement)
What is a study conducted by Fadiga et al using transcranial magnetic stimulation on mirror neurons?
METHOD
- It is possible using TMS on the surface of the motor cortex of the brain to elicit a twitch of the corresponding muscle when the current is high enough
- Here, they turned down the intensity of the TMS so it wasn’t enough to trigger a muscle movement
- The participant then watched someone making a movement of the same area the TMS is applied to their own brain
RESULTS
- The combination of low TMS and observation of muscle action caused a muscle twitch
CONCLUSION
- Shows that the use of motor evoked potentials can show that observing an action produces increased motor excitability
What is a study by Buccino et al into similarities across species and mirror neuron activity?
METHOD
- Humans watched three actions:
- Lipreading (human)
- Lipsmacking (monkey)
- Barking (dog)
RESULTS
- Speech and lip-smacking activated the same premotor areas in human and monkey but the dog barking does not
What are the main two differences between humans and monkeys when it comes to mirror neurons?
Humans
- Action does not need to be goal-directed or contain an object (meaningless movements are represented)
Monkeys
- Action must be goal-directed (often involved an actual object)
- Cannot learn novel and complex acts through imitation, mirror neurons may instead underpin understanding and intentions
What 3 things allow us to predict the behaviours of others?
- Imitation
- Empathy
- Intention
What does social cognition require according to Gallese?
Analogy between self and others (embodied simulation)
What are two components of empathy?
Emotional
Sensorily
Explain the sensorily component of empathy
When you see someone hurt themselves, you’ll often move that part of your own body, as if you felt the pain also
Where in the brain was there a mapping of witnessing pain and experiencing it? (Morrison et al)
Anterior Cingulate Cortex
What is a study done by Morrison et al into motor empathy?
METHOD
- Presented one of 4 videos to the ppts
- One with a needle going into the hand, one with a cotton bud touching a hand, one with a needle into a sponge and one with a cotton touching a sponge
- The participant was instructed to press a button when they see a certain coloured shape and then release when they see the same shape
RESULTS
- In the majorty of the conditions, there was a faster press of the button than the release
- In the needle-hand condition people were slower to press and faster to release
CONCLUSION
- The automatic taking on of the movement is correlating to the emotional empathy which correlated to their self-report empathy
What is the Chameleon effect?
Empathetic individuals often exhibit non-conscious mimicry of postures, mannerisms and facial expressions of others
What is the correlation between high scores in empathy measures and the chameleon effect?
If you score high on empathy measures, you’re more likely to show an increased chameleon effect and have more social interactions
What are the triad of impairments in Autism?
- Social Interaction- solitary, withdrawn, little eye contact
- Communication- language impairment, difficulty understanding others (especially indirect meaning)
- Restricted and repetitive interests
What are three major theories of autism?
- Theory of Mind defecit (difficulty mentalizing that other people know different things to themselves)
- Weak central coherence (focus on detail at the expense of bigger picture)
- Broken mirror theory (issue with the mirror neurons)
What 3 problems could the broken mirror theory explain for those with autism?
- Problems imitation
- Difficulties with empathy/social cognition
- Difficulties with metaphor and indirect meaning
What is a study on action observation in autism?
METHOD
- Looked at the observation of actions in autistic children
- Watch a person with a pot on their shoulder and they reach forward picking up a piece of food or paper
- If food- infer that it will go in mouth, if paper- infer that it will go in the pot
- Also carry out the actions
RESULTS
- Recorded muscles from the face to do with openinig the mouth
- In controls if there is paper, there is no opening of the mouth and if there is food there is predicor mouth opening before food reaches
- In autisitc children, they do not open their mouth for food in advance
- When observing, the controls open their mouth slightly when watching someone else put food in their mouth
- In autistic children there is no opening of the mouth when watching others do the task
What are Dinstein et al’s points of critique for the mirror neuron system?
- How ‘selective’ are MNs for different types of action?
- Limitations of evidence from primates
- Limitations of evidence in humans
What are the limitations in primate data that Dinstein et al claims?
- Small number of examples
- Often qualitative rather than quantitative
- Need more studies to ask how well cells can distinguish pairs of movement
- Need evidence of MNs firing in spontaneous social interaction
What are the limitations in human data that Dinstein et al claims? (MN)
- Many areas outside of ‘MN’ areas are activated during action
- Are the same neurons firing? Adaptation protocols
- TMS effects could be produced by areas outside of MN
What is the adaptation task?
METHOD
- If use the same neurons several times, there will be adaptation and a reduction in response
- Repeated the action of rock paper or scizzors and measured to see if observing the same action or a different one would cause a different neural response both observed and actually doing it
RESULTS
- Overlapping areas showed adaptation for observed and executed
- No evidence for adaptation across modalities
What are three problems for the MN theory in monkeys and humans according to Hickok?
- Motor theories of perception are not new
- Do mirror neurons go beyond other sensory-motor neurons?
- Over-emphasis on ‘action understanding’ function
What is the support for Hickok’s claim that “There is no evidence in monkeys that MNs support action understanding”
- Inactivation of F5 disrupted grasping but not perception
- Kohler et al- sound of action evidence could just be an association so might not mean the sound helps the monkeys understand
- Umilta et al- hidden actions evidence could just be about working memory
- Researchers have inferred that monkeys are understanding the action but have not actually measured it
What is a study conducted by Fogassi et al onto distinguishing two actions with different roles in monkeys?
METHOD
- Looked at distinguishing between two actions with different roles, grasping to eat and grasping to place
RESULTS
- Found that some cells respond more to one action than the other action
- Cells in the inferior parietal lobule respond to the goal of the action (grasping to eat versus place
- Same reference is observed when the action is exectutes compared to observed
What is the supporting evidence for Hickok’s claim: “action understanding can be achieved without MNs”?
- F5 also responds to objects, but it is not argued to underpin understanding of objects
- Another region such as Superior Temporal Sulcus may be more critical for action understanding
What is supporting evidence for Hickok’s claim: “human-monkey differences”?
- Higher cognitive functions attributed to MNs are not seen in monkeys
- Assumed that MN in humans has developed to include both action understanding and imitation
- Cannot assume that conclusions from monkey MNs apply in humans e.g. few human imaging studies examine overlap between observation and own action
What is the supporting evdence for Hickok’s claim: “Human action understanding dissoiates from MN areas”?
- Dog barking did not activate MN system in humans
- Surely they understood the action
- Calvo-Merino Ballet dancers v Capoeira (cannot understand how to do the other experts dance, so saw greater activation when witnessing the dance that they were an expert in). There was still activation to non-expert dance even thought they couldn’t do the actions
Where is there greater activation for in experts brain when watching their own area of expertise? (4)
- Ventral pre-motor
- Dorsal pre-motor
- Inferior parietal sulcus
- Posterior STS
What do Jacob and Jeanerod claim about motor cognition and social cognition?
- Motor intention is not the same as social intention
- Can perform the same action but with different intentions driving it
- Used the example of Jekyll and Hyde
What are 4 problems with the broken mirror theory of autism?
- Effects may be due to activity outside of MN areas
- MN problems cannot explain preference for local detail and sensory problems
- People with ASC can recognise and predict actions
- People with ASC can imitate under some conditions
Why can children with ASC recognise certain actions?
- Meaning of the action, the direct route is important but affected
- Autistic children can perform goal-directed imitation
- Autistic adults look more to a goal than the means of an action
- Kiniematics are important as well as what is achieved at the end of the goal
What are some areas in which the broken mirror theory needs to be improved?
- Need to better understand other processes involved in imitation
- Could other mirror areas (limbic, somatosensory) be involved?
- Should people be looking for a single explanation for problems in ASC?
What are three things that most actions require to control movement?
- Multiple muscles
- Precise timing (e.g. between the two hands)
- Multiple components of movement
What are 4 higher cognitive processes involved in motor control?
- Planning and timing
- Sequencing
- Imagery
- Expertise
How can we apply knowledge from studying motor control to everyday life?
- How best to learn motor skills
- Rehabilitation of patients with difficulties with movement
- Using knowledge of human movements to create artificial limbs/robots
What brain area is most concerned with execution of a movement?
Primary motor cortex
What brain area is most concerned with preparation of actions?
Premotor cortex
What brain area is most concerned with higher level of planning?
Prefrontal cortex
What brain area is most concerned with sensory-motor links?
Parietal Cortex
What is another name for the primary motor cortex (M1)
Pre-central gyrus
How is the primary motor cortex organised?
Somatotopically
What do activations of particular M1 areas cause?
Movements of particular body parts in the contralateral side of the body
What is Hemiplegia?
Paralysis of one side of the body
What is Hemiparesis?
Weakness of one side of the body
How do M1 cells code for movement?
- Each cell has a preferred direction of movement
- Populations of cells code the direction of movement
- This is called vector coding
What is new evidence contradicting the homunculus theory?
- There are body specific areas for fine motor control located in the brain
BUT
- There is a somato-cognitive action network for integrating goals and whole body movement also
Where is the primary somatosensory cortex located?
Behind the central sulcus (post-central gyrus)
What concerns the primary somatosensory cortex?
Receives information from the body
What are the main M1 inputs?
- Supplementary motor area
- Premotor area
- Primary somatosensory area
What are the M1s main outputs?
The spinal cord for the control of muscles
What are two areas within the premotor cortex?
- Lateral premotor cortex (externally generated actions)
- Supplementary motor area (medial prefrontal cortex)- internally generated actions
What 3 brain areas are involved in coordinating bimanual movements?
- Cerebellum
- Supplementary premotor cortex
- Lateral premotor cortex
What is sequence learning used to measure and what is it?
- Look at learning in the lab
- Asked to learn and produce a sequence of 8 key presses
- Make many errors at the beginning, but gradually make less and less with practice
- Can look at the change for more effortful to more automatic sequences
What areas have differnet activations over the duration of sequence learning?
- Supplementary motor area increases
- Dorsolateral prefrontal cortex decreases
- Lateral premotor cortex decreases
- Primary motor cortex decreases
What does repetative TMS cause?
Stops the activity in a particular brain area as fatigues the cells there
What actions were affected when TMS was conducted on the supplementary motor area?
- Simple and medium complex tasks were unaffected
- Complex tasks were impaired due to TMS
What are 4 actions that the prefrontal cortex is involved in?
- Choosing what action to perform
- Attention to action- when difficult or learning
- Longer term goals and intentions
- Not specific to action e.g. generating random numbers
What 4 errors can prefrontal lesions produce?
- Perseveration
- Utilisation Behaviour
- Disinhibition
- Frontal apraxia
What is perseveration?
Repeat the same action when no longer relevant
What is utilisation behaviour?
Act on irrelevant (or inappropriate) object in the environment
For example putting on some glasses that are sat on a table
What is disinhibition?
Reduced ability to control an action
What is frontal apraxia?
Not being able to follow steps in routine tasks such as making a tea
What is the Antisaccade task used to test for disinhibition?
- Sat in front of a screen
- Light flashes in the corner
- Participant must not look to the light but instead the oposit direction
- Must inhibit the tendency to look at the target
- For those with prefrontal lesions, they are more likely to look to the light
What are the two sections of Normal and Shallice’s model into conducting actions?
- Contention scheduling- selects appropriate schema
- Supervisory attentional system (SAS)- required for novel/ less automatic actions
How can Normal and Shallace’s model explain perservation and utilisation behaviour? (2)
- Perservation- unable to change schemas when no longer appropriate
- Utilisation behaviour- schemas activated by environment without SAS suppressing them
What area of the brain is involved in sensory motor links?
Parietal cortex
What can damage to the parietal cortex cause?
Apraxia
What is apraxia?
An inability to perform skilled purposeful movements
What is Ideomotor Apraxia?
- Idea and execution are disconnected but retain knowledge of an action
- Can recognise action performed by another
- Fail in pantomining an action
- Can perform sequence but not components
What are two important subcortical motor areas?
- Basal Ganglia
- Cerebellum
What occurs when there is damage to the cerebellum? (5)
- Action tremor
- Dysmetria (over and undershooting of movements)
- Defecits in coordinating across joints
- Defecits in motor learninig
- Defecits in timing
What is the random saccade test and how do cerebellar patients perform?
- Simple task of following a target and moving the eyes to track
- Cerebellar patients, under and overshoot the target
How do cerebellar tremors affect the finger-to-nose test?
Amplitude increases as the finger nears the target (gradual increase in tremor)
How do Parkinson’s tremors affect the finger-to-nose test?
Tremor may present at the beginning of the movement and smooth near the nose
How do essential tremors affect the finger-to-nose test?
The tremor is manifested throughout the test, possibly worsening as the finger approaches the nose
What is the prevalence of Parkinson’s disease?
- 1 in 1000
- 1 in 100 over 65 years old
What are 4 movement symptoms in those with Parkinson’s disease?
- Bradykinesia- slow movement
- Tremor (resting)
- Rigidity
- Shuffling
What causes Parkinson’s disease?
Death of dopiminergic cells in the substantia nigra pars compacta
What does a person with Parkinson’s handwriting look like?
- Small in size
- May reduce while writing- fatigue
What are 3 deficits seen in Parkinson’s disease?
- Internal/external- more problems with internally generated movements
- Complex movements- bimanual sequences
- Cognitive effects- attention shifting, everyday cognitive failures
What area of the brain has implications in Parkinson’s?
Basal Ganglia
What does GPl stand for?
Lateral Globus Pallidus
(Globus Pallidus Internus)
What does GPm stand for?
Medial globus Pallidus
(AKA GPe - Globus Pallidus external)
What does SNc stand for?
Substantia Nigra pars compacta
What does STN Stand for?
Subthalamic Nucleus
What are the two pathways in the basal ganglia?
Direct and Indirect
What is the direct pathway of the basal ganglia concerned with?
Excitatory effects
What is the indirect pathway of the basal ganglia concerned with?
Inhibitory effects
Where does information that enters the basal ganglia go into?
Putamen (receives input from cortical areas)
What area of the basal ganglia to projections leave from?
GPm (projects back to the cortex)
What are the 4 steps of the direct pathway in the basal ganglia?
- Excitatory signal from cortex
- Increased inhibitory signal from putamen to GPm
- Reduced Inhibitory signal from GPm to Thalamus
- Increased excitatory signal from thalamus to motor cortex
What are the 5 steps of the indirect pathway in the basal ganglia?
- Increased inhibitory signal from putamen to GPl
- Reduced inhibitory signal from GPl to STN
- Increased excitatory input to GPm
- Increased inhibitory output to thalamus
- Reduced excitatory output to cortex
How does the basal ganglia act as a gain control?
Direct pathway- allows desired movements to occur through disinhibition
Indirect pathway- prevents undesirerd movement occuring
What effects does a lack of dopamine have on the two basal ganglia pathways?
- Underactive direct pathway (increased GPm activity)
- Overactive indirect pathway (increased GPm activity)
- Both lead to increased inhibition of the thalamus and reduced excitation of the cortex
What other functions does the basal ganglia have besides motion?
- Cognitive functions
- Due to different basal ganglia loop projections
What is the treatment for Parkinson’s?
- L-dopa (can cause dyskinesias)
- Newer dopiminergic drugs (agonsti medication)
- Surgery- lesions and deep brain stimulation
How does deep brain stimulation work for Parkinson’s?
- Electrode implanted into the basal ganglia (Targets STN, GPi/L, Thalamus)
- Battery operated stimulator delivers electrical stimulation to targets
-Can adjust the parameters of the stimulation overtime unlike more permanent surgery
How does deep brain stimulation reduce the effect of the indirect pathway?
Stimulation inhibits the firing of the associated region.
- Reduced activity in the STN
- Reduced excitation of the GPm
- Reduced inhibition of the thalamus
- Greater excitation of the motor cortex
What is Huntington’s disease?
(Genetically)
An inherited, autosomal dominant condition
When is huntington’s onset?
30s or 40s
What is the main symptom of Huntington’s
Chorea (uncontrolled movements)
What causes Huntington’s?
Degeneration of putamen and caudate
How does huntington’s affect the basal ganglia pathways?
- Underactivity of indirect pathway
- Reduced inhibition of GPl
- Increased inhibition of STN
- Reduced activity of GPm
- TOO MUCH MOVEMENT
What are the cognitive impairements of Huntington’s?
- Attention
- Executive Function
- Speed of Processing
- Prospective memory
- Emotion recognition
What are the characteristics of tourettes syndrome?
- Simple tics- eye blinking
- Complex tics- gestures and utterances
- May increase during times of stress and decrease when concentrating
Summarise tourettes syndrome.
- > 1000 per 100, 000 (greater than 1 in 1000)
- 4x more common in boys
- Hereditary
- Links to OCD
- Developmental conditon
How does tourettes affect the basal ganglia pathways?
- Increased dopamine from the substantia nigra
- Overactivity of the direct pathway leading to disinhibition of an unwanted movement
What is an aberrant focus in terms of tourettes syndrome?
An undesired movement is active in the striatum leading to activity in the direct pathway
Which condition has an overactive direct pathway?
Tourettes
Which condition has an underactive direct pathway and overactive indirect pathway?
Parkinson’s
Which condition has an underactive indirect pathway?
Huntington’s
