mirror neuron system

Question 1

where are mirror neurons found in the brain?

Answer 1

ventral premotor cortex and inferior parietal lobe
– transform sensory representation of observed/heard motor acts into similar motor acts

insula and rotral cingulate
– transform emotional situations into similar visceromotor emotional responses

prefrontal cortex and language areas
– transform observation of intransitive (no goal) motor actions or sound into imitation

Question 2

describe the neuroanatomy of the fronto-parietal mirror neuron system

Answer 2

there are three main fronto-parietal areas which contain mirror neurons:
– ventral premotor cortex, F5
– area PFG
– anterior intraparietal area

the fronto-parietal circuit receives input from superior temporal sulcus and the inferior temporal lobe

the fronto-parietal is controlled by:
– ventral premotor cortex
– frontal lobe (F6 or supplementary motor cortices)

Question 3

in which areas are mirror neurons active during action (intention)

Answer 3

inferior + middle frontal gyrus

inferior + superior parietal lobule

inferior temporal gyrus

ventral premotor area

cerebellum

Question 4

in which areas are mirror neurons active during empathy/emotion

Answer 4

cingulate gyrus

insula

amygdala

Question 5

how do we understand the intentions of others?

Answer 5

fMRI shows activity in the inferior posterior frontal gyrus increases when shown the same motor action in different contexts

this is consistent with the involvement of the mirror neuron system in understanding the intentions of others

humans do not develop this ability until 3-4 years of age

also helps us understand the actions of other species

increased activity in inferior parietal lobule and ventral premotor cortex when humans shown biting action in humans, dogs and monkeys

Question 6

how does MNS activity correlate to autism

Answer 6

decreased activity in the MNS strongly correlates to autism

autism involves:
– motor deficit
– language impairment
– social impairment

Question 7

describe the action-intention mirror neuron system in primates

Answer 7

in primates, mirror neurons were first discovered in the F5 area of the ventral premoter cortex. these mirror neurons fired when:
– monkey grasped for food
– experimenter / other monkey grasped for food
– monkey saw/heard motor act
– motor act was partially hidden to monkey

Similar neurons were found in the inferior parietal lobule (IPL)