Lecture 8 - Perception of Action/Mirror Neurons Flashcards
What is a crossmodal transfer?
We map visual representations of actions onto our motor systems to produce copy of it (so good at it some think ability is innate)
Evidence: infants imitate caregivers facial expressions, hand/mouth movements, head turns, etc. –> babies build representation of visual image + map onto own motor representations
What did Meltzoff/Moore study?
Babies aged 12-21 days could imitate certain facial expressions + specific acts (eg. Lip protrusion/tongue protrusion) even after delay
What evidence is against neonate (infant) imitation?
Longitudinal study found matching model behaviour more likely compared to some but not other control behaviours –> true imitation may be 6-9 months
What is Active Intermodal Matching (AIM)?
Neonates (infant) recognise equivalence between body transformations they see + those of their own body that they feel themselves make
Baby’s emotional expressions induce adults to produce similar expressions, provides infant w/ visual input to match motor output
What does AIM involve in comparison to other models?
Involves perception + action having independent coding/representation, specialist module for imitation
Other theories (IM/ASL) posit: common coding for perception + action, imitation part of “generalist processes for motor control/learning
What is Ideomotor (IM) theory?
Stimulus –> sensory representation–> motor representation–> motor program
What is Associative Sequence Learning (ASL)?
Emphasises learning through experience (eg. See consequence of own hand action)
What is dual route of imitation?
Input action –> visual analysis –> long term semantic memory –> ST/WM –> output action (Direct route from visual analysis to ST/WM available)
Incorporates aspects of other models, semantic (meaningful actions stored in repetoire), visuomotor/direct (meaningless actions/mirror neurons)
What are mirror neurons?
Same neurons found active when monkey performed + watched action
General properties: bimodal, visuo-motor neurons (respond to both visual/motor stimuli), discharge when individual performs action + when observe same action performed by another individual
Underpin action understanding: Umilta et al. (2001) - MNs active during observation of partially hidden actions (predicts), Kohler et al. (2002) = audio-visual MNs respond to sound typically produced by action
Where are MNs found?
Monkey area F5 of premotor cortex/inferior parietal lobe,
contains 3 types of neurons (monkeys): action observation related, motor, canonical visuomotor neurons
Broca’s area/inferior frontal gyrus/posterior parietal lobe/superior temporal lobe for humans (somatotopically organised)
What indirect evidence is there for humans MNs?
Close link between perception/action: motor imagery – imagined movement w/out action, overlap in brain activity between imagined/observed/executed movements, meta-analysis across studies
Behavioural: faster responses when compatibility between observed/executed movements (automatic imitation), observe upward movement = faster to lift finger up/slower to press down
Brain imaging (fMRI): somatotopic activation of premotor/parietal cortex, areas correspond to observation of actions/diff body parts
TMS: use motor evoked potentials to show that observing action produces increased motor excitability
What direct evidence is there for MNs in humans?
Recording from neurons: recorded neurons in 21 patients undergoing surgery for intractable epilepsy, observed/executed grasping actions/facial gestures, action observation related MNs in medial frontal lobe (supplementary motor area/SMA)/medial temporal lobe (hippocampus)
Species similarities/diffs for MNs?
S: Human/monkey/dog actions – same areas activated to movements common to all three species (eg. Biting), speech/lip-smacking activates same area in human + monkey but not dog barking
D: Human – action doesn’t need to be goal-oriented, monkey – action must be goal-directed (often involve actual object), can’t learn novel/complex acts, MNs for monkeys may underpin understanding intentions
