Social Cognition and the Mirror Neuron System

Jaime A. Pineda, Ph.D. Cognitive Neuroscience Laboratory

COGS1 class

Motivating Questions

•  How do we perceive the mental states of others?

–  How do we read other minds?

•  How do we understand the actions, emotions and the intentions of others?

–  Rationally? –  Intuitively?

•  How do we understand first- and third-person experiences?

Classic Explanation

•  Theory-Theory (argument from analogy; disembodied knowledge;

visual hypothesis)

–  Involves striate, extrastriate, inferotemporal lobe and superior temporal sulcus, among others

A Different Perspective

•  Simulation Theory (Direct-matching hypothesis; embodied knowledge)

–  Map visual onto motor representations of the same action

•  Mirroring systems –  Perception-action mechanisms that allow

for simulation •  Mirror neurons •  Mirror Neuron System •  EEG Mu rhythms

A Different Perspective

•  Simulation Theory (Direct-matching hypothesis; embodied knowledge)

–  Map visual onto motor representations of the same action

•  Mirroring systems –  Perception-action mechanisms that allow

for simulation •  Mirror neurons •  Mirror Neuron System •  EEG Mu rhythms

–  What happens when simulation is damaged?

•  Aspects of autism?

Mirror Neurons

•  Discharge when the monkey performs an action and when it observes a similar action done by another agent

–  Found in: •  area F5 (homolog of Broca’s area) •  inferior parietal cortex (PF/PFG/7b)

–  Activated by: •  Goal directed actions (reaching, grasping, holding) •  Observation of similar actions

performed by “biological” agents

Di Pellegrino et al., Exp. Brain Res., 1992, 91, 176-80

Rizzolatti et al., Cogn. Brain Res., 1996, 3:131-141

Mirror Neuron Activity

Perception-to-Action Mapping Selectivity

Action

Logically-Related (effector independent; 2X)

Congruent (effector dependent)

Perception

Significance

–  Strictly congruent mirror neurons may encode how an observed action is performed the kinematics of the action (means plus the goal)

–  Broadly congruent mirror neurons may encode only the goal of the action what it tries to achieve, irrespective of how it is achieved (ends)

Understanding Goals and Intentions?

Umilta et al. Neuron, 2001, 32: 91-101

Grasping Mimicking

The Action-Perception or Mirror Neuron System

Iacoboni and Dapretto, Nature Reviews, 2006,7:942-951

•  Response facilitation •  Mimicry •  Simulation •  Imitation learning •  Understanding actions •  Understanding intentions •  Empathy •  Theory of Mind •  Language

Functional Significance

The Mirror Neuron System

Iacoboni and Dapretto, Nature Reviews, 2006

mu rhythm (8-13 Hz)

MNS Activity --> Suppression

Normal Oscillations at rest

Mu Rhythm

•  8-13 Hz oscillation over sensorimotor cortex

Normal Oscillation Self Action Observed Action No mirroring Motor + Mirroring Mirroring only

Frequency Analysis of Mu Rhythm

Power

Frequency

(8-13 Hz)

(10-14 Hz)

Autism Spectrum Disorders (ASD) (Leo Kanner, 1943)

  Problems with:   Repetitive movements and restricted interests   Language and communication   Social ability

Common Characteristics of Social Dysfunctions

–  Impairment in social play and imagination –  Difficulty interpreting actions and intentions

of others –  Inability to participate in a reciprocal

conversation –  Language delays –  Impaired joint/sustained attention –  Trouble imitating others –  Absence or reduced empathy

Hypothesis

•  If mu rhythms reflect mirroring activity and the capacity to understand actions as well as learn through imitation, then children on the autism spectrum should show differences in mu rhythms compared to controls

Oberman et al., Cog. Brain Res. 2005, 24: 190-198

Experimental Paradigm

•  Measured mu power (2 min of EEG) in normals (n=12) and autistics (n=10) under different conditions:

–  Self-movement of hand

–  Watching video of someone moving their hand

–  Watching a video of a ball moving up and down

Oberman et al., Brain Res Cogn Brain Res. 2005, 24(2):190-8.

Results

Oberman et al., Neuropsychologia, 2008

Is the Mirror Broken and Unrepairable?