5b - perception of action, imitation

what is a unique human ability

we are really good at imitating other peoples’ actions - this is called perception-action mapping

• we map visual respresentations onto our motor systems (crossmodal transfer)

crossmodal transfer

visual representations being mapped onto our motor systems

what is evidence for perception-action mapping

infants can imitate caregiver’s facial expressions, hand and mouth movements etc.

• meltzoff and moore found this was present in babies as young as 12 days old (tongue protrusion) whilst piaget thought it occurred no earlier than 1 year

what evidence is there against neonate imitation

more rigorous study challenges previous evidence Oostenbroek - found true imitation may emerge at 6-9 months

what is Active Intermodal Matching (AIM)

• neonates recognise equivalences between body transformations they see and those of their own body that they ‘feel’ themselves make

• babys emotional expressions induce adults to produce similar expressions, which provides the infant with a visual input to match their motor output

how does AIM compare to other models

AIM involves:

• a perception and action having independent coding/representation

• a ‘specialist’ module for imitation

other theories (IM and ASL) suggest:

• common coding for perception and action

• imitation part of generalist processes for motor control and learning

outline Ideomotor (IM) theory

Associative Sequence Learning (ASL) - emphasises learning through experience e.g. see consequence of own hand action

what is the dual route of imitation

• incorporates aspects of the other models

• SEMANTIC: meaningful actions stored in repetoire

• VISUOMOTOR/DIRECT: meaningless actions/mirror neurons

what are mirror neurons

• same neurones found to be active when the monkey performed and watched an action

when did Umlita et al find regarding mirror neurons

mirror neurons active during observation of even partially hidden actions

• predicts action outcome even in absence of complete visual information

• no response in the absence of an object

what did Kohler et al. (2002) find regarding audio-visual mirror neurons

responded to the sound typically produced by the action → BUT for sound only, there is less MN action beforehand as they can’t predict the action

where are mirror neurones in monkeys and humans

in monkeys: f5 area of premotor coretex and inferior parietal lobe

in humans: broca’s area BA44, ventral inferior frontal gyrus (BA6), posterior parietal lobe and superior temporal lobe

• somatotopically (according to body part) organised

what actions do mirror neurons react to

goal-directed

what indirect and direct evidence is there for human mirror neurones

indirect: close link between perception and action, behavioural, brain imaging fMRI, transcranial magnetic stimulation (TMS)

direct: recoding from neurones

what behavioural evidence is there for MNs

faster responses when compatibiity between observed and executed movements

• known as ‘automatic imitation’

what did Buccino et al find regarding somatotopic activation

activation of pre-motor and parietal cortex - corresponded to observations of actions of different body parts

what did Harwick et al find about perception-action overlap

motor imagery imagined movement without actionn

• overlap in brain activity in imagined, obsreved and excecuted movements (meta-analysis)

how is the Human MNs affected by tms

used motor evoked potentials to show that observing an action produced increased motor excitability

outline mukamels study

recorded 1177 neurons in 21 epilepsy patients undergoing surgery for epilepsy

• observed and excecuted grasping actions and facial gestures

• action observation related ‘mirror’ neurons found in medial frontal lobe (supplementary motor area (SMA) and medial temporal lobe (hippocampus)

• also found that some respond with inhibition during observation

what are other purposes for mirror neurons aside from movement

• evolution of language

• empathy and social cognition (broken mirror theories of autism and schizophrenia)

what is intersubjectivity

imitation, empathy, intention (mind-reading) - allow us to predict the behaviours of others

• Gallese - ‘like me’ embodied simuation analogy between self and others which forms the basis of social congition

• based on the process of crossmodal transfer and the mirror matching system

outline empathy

relates not only to how you are feeling ‘emotionally’ but also ‘sensorily’ → when you see someone hurt themselves you will move to that part of your own body as if you were hurt too

where is the overlap for seen and felt pain

direct mapping of viewing pain in others and feeling pain in yourself in the cingulate cortex (BA24b)

how was motor empathy measured

• 4 videos; hand/sponge touched by needle/cotton bud → pps alternated pressing and releasing after each video

• pps were faster to press responses than release responses except when people viewed the needle touching hand

what are limitations of primate data

• small number of examples

• often qualitative rather than quantitative

• need more studies to distinguish how well cells can distinguish pairs of movement

• need evidence of MNs firing in spontanous social interaction

what are limitations with human data in MNs

• many areas outside MN areas activated during action observation → TMS effects could be produced by areas outside MN

outline adaptation tasks in MN research

• adaptation can be used to see if the same area is involved in different tasks → overlap in areas adapting for observed and executed (e.g. anterior inferior frontal sulcus, ventral premotor and posterior lobe.

• no evidence found for adaptation across modalities

evaluate the existence of MNs

• Hickok: motor theories arent new, over-emphasis on ‘action-understanding function’

• sound experiement could be an association

• hidden actions could just represent working memory

• there isnt a measurement of understanding

what other areas could be responsible for action understanding

• STS superior temporal sulcus may be more crucial for action understanding (dot people)

• F5 also responds to objects

what are human-monkey differences in MN

• higher cognitive function attributed to MNs are not seen in monkeys

• assumed that MN in humans has developed to include action understanding and imitation

• cant assume that conclusions from monkey MNs apply in humans

how does human action understanding dissociate from MN areas

human, monkey and dog actions:

• same areas activated for movements common in all species e.g. biting

• speech and lip-smacking activates same area but not dog barking

  • but surely humans understood dog bark

how did expert actions represent in MNs

• Ballet dancers v Capoeira - greater activation for experts

  • there was greater activation in the ventral and dorsal pre-motor areas, inferior parietal sulcus, posterior STS

• actions only done by male ballet dancers was less prominently mirrored in female brain

can we understand intention without action

yes → heider-simmel, bully triangles

we can also understand more than one agent - cannot simulate both actions