Social Cognition and the Mirror Neuron System of the Brain Jaime A. Pineda, Ph.D. Cognitive Neuroscience Laboratory COGS1 class
Motivating Questions How do our brains perceive the mental states of others despite their inaccessibility? 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 information onto motor representations of the same action Mirroring systems bridges between perception and action that allow for simulation Mirror neurons EEG Mu rhythms
A Different Perspective Simulation Theory (Direct-matching hypothesis; embodied knowledge) Map visual information onto motor representations of the same action Mirroring systems bridges between perception and action that allow for simulation Mirror neurons EEG Mu rhythms
The Mirror Neuron System Iacoboni and Dapretto, Nature Reviews, 2006,7:942-951
Biological Motion Visual system's ability to Gender recover object information Activity engaged in from sparse input Emotional state
Biological Motion Perception: Monkeys Perret and colleagues (1989; 1990; 1994) Cells in superior temporal polysensory area (STPa) of the macaque temporal cortex appear sensitive to biological motion Oram & Perrett, J. Cog. Neurosci., 1994, 6(2), 99-116
Biological Motion Perception: Humans An area in the superior temporal sulcus (STS) in humans responds to biological motion Other areas do as well, including frontal cortex, SMA, insula, thalamus, amygdala Grossman et al. J. Cog. Neurosci., 2000, 12(5), 711-720
Brain Circuit for Social Perception (SP) • SP is processing of information that results in the accurate analysis of the intentions of others • STS involved in the processing of a variety of social signals Allison et al., Trends in Cog. Sci., 2000, 4, 267-272
Mirror Neurons A specific class of neurons that discharge both when the monkey performs an action and when it observes a similar action done by another monkey or an experimenter Found in: area F5 (homolog of Broca’s area); 10-20% inferior parietal cortex (PF/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
Mirror Neuron Activity Rizzolatti et al., Cogn. Brain Res., 1996, 3:131-141
Perception-to-Action Mapping Selectivity Congruent Logically-Related (effector dependent) (effector independent; 2X) Perception Action
Understanding Goals and Intentions? Grasping Mimicking Umilta et al. Neuron, 2001, 32: 91-101
Functional Significance Response facilitation Mimicry Simulation Imitation learning Understanding actions Understanding intentions Empathy Theory of Mind Language
Characterizing the System generalizability? motivational significance? biological realism? intentionality?anthropomorphism? social relevance? transitive/intransitive actions? learning? MNS activity No MNS Activity
The Mirror Neuron System mu rhythm Iacoboni and Dapretto, Nature Reviews, 2006,7:942-951
Frequency Analysis of Mu Rhythm (8-13 Hz) P o (10-14 Hz) w e r Frequency
Does Mu Suppression Reflect Mirror Activity ? Baseline Move Observe Imagine Pineda et al., IEEE Trans. Rehab. Engr., 2000, 8(2): 219-222
Mu Rhythm 8-13 Hz oscillation over sensorimotor cortex Normal Oscillation Self Action Observed Action
Action Observation and Social Interaction To what degree do mu rhythms, like mirror neurons, reflect social interaction? Oberman et al., Social Cognitive and Affective Neuroscience, 2007, 2, 62-66
Experimental Paradigm Measured mu power (2 min of EEG) in normals (n=20) ages 18-34 (mean=21.1, SD=3.40 ) under different observation conditions: Non-interacting Social Action - Spectator Social Action - Interactive Visual white noise Engaged in continuous performance task during observation
Non-interacting Social Action - Spectator Social Action - Interactive
Results
Results
Autistic Spectrum Disorder ASD shows impairments in: social interactions delayed/abnormal language development behavior Impaired imitation Repetitive patterns of behavior No common underlying mechanism Deficits in imitation learning (Rogers and Pennington, 1991) Deficits in mirror neuron system (Williams et al., 2001)
Hypothesis If mu rhythms reflect MNS activity and the capacity to understand actions as well as learn through imitation, then autistics 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
Is the Mirror Broken and Unrepairable? Oberman et al., Neuropsychologia, 2008
Creating a Temporary “Autistic” Brain RATIONALE Sensorimotor cortex If mirror neurons in IFG Inferior parietal are involved in the direct lobule modulation of Inferior frontal gyrus sensorimotor mu rhythms, then temporary inhibition Superior temporal sulcus of these neurons should prevent suppression of mu rhythms and cause “autistic-like” behaviors.
Method: Transcranial Magnetic Stimulation Measured EEG in typically developing adults (n=8) before and after IFG stimulation Observation of movement (4 videos) Simple (hand movements) and complex (social interactions) Baron-Cohen’s Eyes Task Emotion and gender discrimination 1 Hz rTMS (5 min at ~ 40-50% absolute threshold) targeted at left IFG
Eyes Task
Results Accuracy Reaction Time
Absence of Mu Suppression
Neurofeedback Training Rationale Frontoparietal areas in an ASD brain may be underconnected If we change the dynamics of the SM sensorimotor mu oscillations , Cortex IPL And these oscillations are functionally linked to the MNS IFG network (IFG, IPL, STS), STS Then we may change functional connectivity via neuroplasticity and recover MNS engagement, leading to positive changes.
Reversing Social Deficits in Autism Training 30 min x 3/week x 10 weeks HF ASD: 7-17 yr olds; n=20 Experimental/Control groups Mu activity above threshold (E) EMG activity below threshold (E/C) Pineda et al., Research in ASD, 2008
Assessments Verification of diagnosis (IQ, ADI, ADOS) Quantitative EEG (QEEG) Test of Variable Attention (TOVA) Imitation ability (De Renzi’s Apraxia imitation test) Mu suppression index (MSI) Autism Treatment Evaluation Checklist (ATEC - parental assessment) Neuroimaging (fMRI, fcMRI)
Interpreting Facial Expressions: Nonverbal Emotion/Gender discrimination
Decoding Thoughts and Intentions Mental attribution Physical causation
Behavioral Performance ASD TD
Mu-Suppression Normalizes Following Training Baseline Hand Social
Positive Changes in Sustained Attention Improved ability to maintain attention in experimental group
Positive Changes in Parental Assessment Autism Treatment Evaluation Checklist
Imitation
Future: Neuroimaging Techniques structural Diffusion Tensor Imaging Functional connectivity functional
A Fundamental Feature of Brain Organization? “Understanding others as intentional agents may be grounded in the relational nature of our interactions with the world” Beyond understanding actions emotions: the root of empathy? sounds and other senses language Other problems in “mirroring” Aberrant imitation learning: addiction?
What Is It Like To Be…? Can aspects of subjective experience be reduced to brain activity? Thomas Nagel, The Philosophical Review 83 (1974).
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