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Understanding Actions: Mu Rhythms and Mirror Neurons. Jaime A. Pineda, Ph.D. Cognitive Neuroscience Laboratory November 23, 2004. Reading Minds. Understanding the behavior of others The capacity to achieve internal descriptions of actions and use them to organize one’s own future behaviors
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Understanding Actions:Mu Rhythms and Mirror Neurons Jaime A. Pineda, Ph.D. Cognitive Neuroscience Laboratory November 23, 2004
Reading Minds • Understanding the behavior of others The capacity to achieve internal descriptions of actions and use them to organize one’s own future behaviors • Neural mechanisms for understanding actions and their intentions • Mirror neurons • Mu rhythms • The effects on learning and social interactions
What Is It Like To Be a Bat? “Consciousness and subjective experience cannot be reduce to brain activity.” Thomas Nagel, The Philosophical Review 83 (1974).
Questions • What are mirror neurons? • How might these neurons help us understand actions and their intentions? • Can they help us understand “what it is like to be …?” • How is mirror neuron activity related to imitation learning? • Is imitation learning important for social interactions? • What’s the relationship between mirror neurons and EEG mu rhythms? • Why would a dysfunctional mirror system produce autistic-like behaviors?
What Is an Action? • Intentional motor behavior • Goal-directed behavior that produces a reward • Attainment of the goal • Increased dopamine release Rizzolatti et al., Nature Reviews, 2001, 2, 661-670
How Do We Understand Actions? • Visual hypothesis • Involves striate, extrastriate, inferotemporal lobe and superior temporal sulcus, among others
An Observation/Execution Matching System? • Direct-matching hypothesis • Map visual information onto motor representations of the same action • Mirror system:direct bridge between perception and action • Mirror neurons • Mu rhythms
An Observation/Execution Matching System? • A dysfunctional “mirror system” produces problems in understanding actions
Visual system's ability to recover object information from sparse input Gender Activity engaged in Emotional state Biological Motion
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, including the amygdala, do as well 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
Reading Other Minds • We understand actions (and intentions) when we map the visual representation of the observed action onto our motor representation of the same action Rizzolatti et al., Nature Reviews, 2001, 2, 661-670
Mirror Neurons • Found in: • area F5 of monkey (homolog of Broca’s area?) • STSa (homolog of Wernicke’s area?), and • inferior parietal cortex (7b) • Activated by: • Goal directed actions (reaching, grasping, holding) performed by “biological” agents • Observation of similar actions • Strictly versus broadly congruent • Do not respond to target alone or intransitive gestures (i.e., nonobject directed) Di Pellegrino et al., Exp. Brain Res., 1992, 91, 176-80
Rizzolatti et al., Cogn. Brain Res., 1996, 3:131-141 Mirror Neuron Activity
Understanding Actions? Grasping Mimicking Umilta et al. Neuron, 2001, 32: 91-101
Functional Significance • Understanding action (Rizzolatti et al., 2001) • Imitation learning (Jeannerod, 1994) • Only in humans and apes?
Mirror System in Humans: Neuroimaging Buccino et al. J. Cogn. Neurosci., 2004, 16: 1-14
Buccino et al. Eur. J. Neurosci., 2001, 13: 400-404 Mirror System in Humans
Neurophysiological Evidence • Gaustaut and Bert, 1954 and Cohen-Seat et al., 1954 • Observing actions of another person blocks mu rhythm (8-13 Hz over sensorimotor areas) of the observer • Recently confirmed • Pineda et al., 1997, 2000 • Cochin et al., 1998, 1999 • Hari et al. 1998
Frequency Analysis of Mu Rhythm Power Frequency
Pineda et al., IEEE Trans. Rehab. Engr., 2000, 8(2): 219-222 Mu Rhythm:Does it Reflect Mirror Neuron Activity? Baseline Move Observe Imagine
Cochin et al., Eur. J. Neurosci., 1999, 11: 1839-1842 Avikainen et al., NeuroReport, 1999, 10: 3467-3470
Characterizing the System generalizability? motivational significance? biological realism? intentionality? social relevance? anthropomorphism? transitive/intransitive actions? learning? Mu suppression (biological actions) No mu suppression (non-biological actions)
Autism: A Dysfunctional Mirror System? • Autistic spectrum disorders are characterized by: • Impairments in social interaction • Delayed/abnormal language development • Impaired imagination • Repetitive and restricted patterns of behavior • No common underlying mechanism has been identified • Deficits in imitation learning – Rogers and Pennington, 1991 • If mu rhythms reflect mirror neuron activity and the capacity to imitate then autistics should show differences in mu rhythms compared to controls
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
Fraternal Twins Normal Autistic
The Root of Empathy? “Understanding others as intentional agents may be grounded in the relational nature of our interactions with the world” • A Fundamental Organizational Feature of the Brain? • Beyond actions? • Audition and other senses • Emotions • Addiction?
What Is BCI? • Brain-based direct communication • Extracting meaningful patterns (signals) • Mapping signals to computer commands • Integrated with keyboard, mouse, and voice recognition
BCI System Feature Extraction Multichannel Pattern Recognition Interface Technology Data Acquisition Mapping to Keyboard Commands Application User
BCI Use Helping impaired individuals have greater mobility Helping impaired individuals communicate Augment average individual’s abilities Recreational/entertainment purposes
Hypothesis Learning to control brain rhythms is faster with active engagement on the task, frequent interactions, feedback, and connections to the real world.
Strategies For High Mu • Imagining movement of hands, bike riding, playing tennis or other athletic activity • Thinking about going right • Maintaining right movement in game • Focusing on word “right” • Shifting attention from word to direction
Strategies For Low Mu • Frustration • Math problems • Calming and relaxing body • Sad memories • Distraction • Exhaustion
Results Predictions HIGH LOW
Collaborators Brendan Z. Allison Eric L. Altschuler Edward M. Hubbard Joseph P. McCleery Vilayanur S. Ramachandran Lindsay M. Shenk Andrey Vankov Victor Wang