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? Thomas Nagel, The Philosophical Review 83 (1974). “Consciousness and subjective experience cannot be reduce to brain activity.”

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,

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

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),

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),

Brain Circuit for Social Perception (SP) Allison et al., Trends in Cog. Sci., 2000, 4, 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

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,

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,

Rizzolatti et al., Cogn. Brain Res., 1996, 3: Mirror Neuron Activity

Understanding Actions? Umilta et al. Neuron, 2001, 32: GraspingMimicking

Functional Significance Understanding action (Rizzolatti et al., 2001) Imitation learning (Jeannerod, 1994) Only in humans and apes?

Buccino et al. J. Cogn. Neurosci., 2004, 16: 1-14 Mirror System in Humans: Neuroimaging

Buccino et al. Eur. J. Neurosci., 2001, 13: 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 PowerPower Frequency

Pineda et al., IEEE Trans. Rehab. Engr., 2000, 8(2): Mu Rhythm: Does it Reflect Mirror Neuron Activity? Baseline Move Observe Imagine

Cochin et al., Eur. J. Neurosci., 1999, 11: Avikainen et al., NeuroReport, 1999, 10:

Mu suppression (biological actions) No mu suppression (non-biological actions) intentionality? anthropomorphism? biological realism? motivational significance? transitive/intransitive actions? generalizability? Characterizing the System learning? social relevance?

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

User Interface Technology Multichannel Data Acquisition Feature Extraction Pattern Recognition Mapping to Keyboard Commands Application BCI System

BCI Use Helping impaired individuals have greater mobility Helping impaired individuals communicate Augment average individual’s abilities Recreational/entertainment purposes

A Brain-Computer Interface

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