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 understand the actions, emotions and the intentions of others? Rationally? Intuitively? How do we understand firstand 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 Pineda, Beh & Brain Functions, 2008, 4, 47 Biological Motion Visual system's ability to recover object information from sparse input Gender Activity engaged in 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 (effector dependent) Perception Action Logically-Related (effector independent; 2X) Understanding Intentions Grasping Umilta et al. Neuron, 2001, 32: 91-101 Mimicking Mirror Neuron System Sensorimotor cortex Inferior parietal lobule Inferior frontal gyrus Superior temporal sulcus Functional Significance Response facilitation Mimicry Simulation Imitation learning Understanding actions Understanding intentions Empathy Theory of Mind Language Characterizing the System motivational significance? intentionality? biological realism? anthropomorphism? transitive/intransitive actions? MNS activity generalizability? social relevance? learning? No MNS Activity Mu Rhythm 8-13 Hz oscillation over sensorimotor cortex Normal Oscillation Self Action Observed Action Frequency Analysis of Mu Rhythm (8-13 Hz) P o w e r (10-14 Hz) Frequency Does Mu Suppression Reflect Mirror Activity? Baseline Move Observe Imagine Pineda et al., IEEE Trans. Rehab. Engr., 2000, 8(2): 219-222 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 Degree of Social Interaction 4 3.5 3 2.5 2 1.5 1 0.5 0 Non-Interacting Social Action, Spectator Social Action, Interactive Results 0.1 C3 CZ 0 -0.1 -0.2 -0.3 Social Action, Interactive Social Action, Spectator -0.4 Non-Interacting C4 Autism Spectrum Disorder (ASD) Problems in the following domains: Social ability Language development Behavior Common Characteristics Impairment in social play and imagination Impaired ability to initiate conversations with others Repetitive behaviors Impaired sustained attention Trouble Imitating others Difficulty interpreting actions and intentions of others Absence of empathy Autism: A Dysfunctional Mirror System? No common underlying mechanism has been identified 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 Results Oberman et al., Neuropsychologia, 2008 Jan 19 [Epub ahead of print] Creating a Temporary “Autistic” Brain Do sensorimotor mu rhythms reflect downstream modulation from cells in premotor cortex? RATIONALE If mirror neurons in IFG are involved in the direct modulation of mu rhythms, then temporary inhibition of these neurons should prevent suppression of mu rhythms and cause “autistic-like” behaviors. Method Measured EEG mu power in typically developing adults (n=8) under different conditions before and after IFG stimulation Observation of movement (4 videos) Baron-Cohen’s Eyes Task Simple (hand movements) and complex (social interactions) Emotion and gender discrimination 1 Hz rTMS (5 min at ~ 40-50% MEP threshold) targeted at left IFG Eyes Task Results Reaction Time Accuracy Results IFG STIMULATION 0.1 0.08 MU SUPPRESSION 0.06 0.04 0.02 0 -0.02 -0.04 PRE -0.06 POST -0.08 -0.1 C3 C4 C3 SIMPLE C4 COMPLEX MOVEMENT TYPE Plasticity Induced Rehabilitation Training Frontoparietal areas in an ASD brain may be underconnected SM Cortex If we change the dynamics of the sensorimotor mu oscillations, And these oscillations are functionally linked to the MNS network (IFG, IPL, STS), Then we may change functional connectivity and recover MNS engagement, Leading to positive changes. IPL IFG STS 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 Pre/Post Assessments Verification of diagnosis (IQ, ADI, ADOS) Quantitative EEG (QEEG) Test of Variable Attention (TOVA) Imitation ability (Apraxia imitation test) Mu suppression index (MSI) Autism Treatment Evaluation Checklist (ATEC) Neuroimaging (fMRI, fcMRI) Pre/Post Assessments Facial Emotions (n-back) Physical Causation - ToM Eyes Emotion Task - ToM Mental Attribution- ToM Behavioral Performance 400 ASD (HITS/MIN)*THRESH 350 300 250 R2 = 0.7673 200 150 100 50 0 0 5 10 15 20 25 SESSIONS 400 TD (HITS/MIN)*THRESH 350 R2 = 0.7068 300 250 200 150 100 50 0 0 2 4 6 8 10 SESSIONS 12 14 16 18 Mu Suppression Index MU SUPPRESSION INDEX LOG [CONDITION/BASELINE] 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 CONTROLS -0.08 EXPERIMENTALS -0.1 HAND SOCIAL PRE-TRAINING HAND SOCIAL POST-TRAINING EEG Coherence Sustained Attention Reduction trend in ADHD score for experimental group Autism Treatment Evaluation Checklist Future: Neuroimaging Techniques structural Diffusion Tensor Imaging functional Functional connectivity A Fundamental Organizational Feature of the Brain? “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). Collaborators and Students Vilayanur Ramachandran Lindsay Oberman Eric Altschuler Andrey Vankov Bill Skinner Chulie Ulloa Brendan Allison Ed Hubbard Joe McCleery Erin Hecht David Brang Scott Carey Adrienne Moore Rajiv Rao Chris Robinson Hanie Elfenbein Alex Bressler Steven Thurman Jena Davis Dong Suk Christa Futagaki Judith Kaye Lee Edwards Ralph-Axel Mueller Brandon Keehn Oriana Clark Jia-Min Bai Derrick Asher Dane Chambers Matt Earhardt Heather Pelton Alicia Trigerio Albert Ayala Stephen Johnson Steve Gilmore Nick Pojman Kelly Head