Autism And Mirror Neurons

1
Autism And Mirror Neurons
2
Autism Spectrum Disorder(ASD)

• Affected people exhibit a wide range in the
  magnitude in their symptoms
• These patients show deficits in
• Communication and Socialization
• Theory of Mind
• Empathy
• Is a dysfunctional mirror neuron system
  responsible for this phenotype?

3
Mirror Neuron(MNs)

• First discovered in Macaque monkeys found to
• Mediate imitation
• Basis of action understanding
• Associates observed actions with motor
  representations of that action

4
Mirror Neurons and Autism

• Mu rhythm desynchronizes during observed movement
  and own movement
• Control participants showed Mu rhythm suppression
  when observing and performing action
• ASD participants had same suppression when
  performing action, but very little or no
  suppression when observing same action
• This proposes a deficit in Mirror neuron activity
  in ASD

5
Mirror Neurons Localized to Brocas Area

• Goldin-Meadow, 1999) Localized a population of
  mirror neurons in the F5 region of the Macaque
  brain that were active during the presentation of
  a communicative mouth gesture
• -(Buccino et al., 2004) Found
  communicative facial gestures also elicit mirror
  neuron activity in the human Brocas Area

6
Mirror Neurons Involved in Language Processing in
Motor Cortex

• -(Hauk, 2004) with fMRI, found that when subjects
  would read passages concerning various body
  features(face, hands etc.) there would be
  corresponding activity in the related motor
  cortex regions.
• -(Fadiga, 2002) Presented subjects with phonemes
  and found motor cortex activity at areas
  concerned with tongue manipulation during speech.

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Theory of Mind

• 2 Models
• Theory Theory
• observing patterned behaviors in others allows
  humans to develop theories to explain and predict
  mental states
• Simulation Theory
• brain simulates the mental processes of others
  putting themselves in the others shoes
• Mirror neurons thought to play a role in ToM

8
Imitation, ToM, and Autism

• Imitation thought to play a role in theory of
  mind
• MN activation allows others to generate an
  executive plan like the one being observed
• Mechanism seems to follow simulation model
• Mirror Neuron Dysfunction can account for social
  problems

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Mirror Neurons and Empathy
Empathy The ability to identify with the
feelings, thoughts, or mental states of other
people (putting yourself in the shoes of
someone else)
Humans are normally able to do this quite well
once fully developed- BUT autistic people seem to
have a lack of empathy.
What allows us to interpret the feelings of other
people? Mirror Neurons! along with a few
other structures
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One proposed pathway of emotional interpretation

• Another persons action is visually encoded by
  the superior temporal cortex
• Mirror neurons in the posterior parietal cortex
  interpret the movement
• Mirror neurons in the inferior frontal cortex
  infer the goal or intent of the action
• Parts of the insula, which receive input from
  all three cortical areas, project to the limbic
  system
• The limbic areas process emotionally relevant
  content
• Meanwhile, the mirror neurons also project back
  to the superior temporal cortex to allow imitation

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The Insula Bridge Between Action Representation
and Emotion
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Mirror Neurons and Empathy

• Dapretto et al (2006) fMRI recordings for the
  observation and imitation of various emotional
  expressions
• Autistic children had
• MORE activity in the right visual and left
  anterior parietal areas (visual and motor
  attention)
• LESS activity in the insula and amygdala
  (emotion)
• NO activity in the mirror neuron system of the
  inferior frontal gyrus

13
Mirror Neurons and Consciousness
Mirror neurons probably play a huge role in many
aspects of our conscious state, particularly
involving interaction with other people
(language, theory of mind, empathy) Are these
abilities crucial to our consciousness? Does the
lack of them (as in autism, at least to some
extent) alter the way we experience the world?
14
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Neural mechanisms of empathy in humans A relay
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