Transcript Gallese - UCSD Cognitive Science

A Unifying View of the Basis
of Social Cognition
by:
Vittorio Gallese, Christian Keysers, and Giacomo Rizzolatti
Amanda Issa
Angela Arreola
Stacy Struhs
Focus of the Paper
• Provide a unifying neural hypothesis on
how individuals understand the actions
and emotions of others
• Claims:
• Fundamental mechanism at the basis of the
experiential understanding of others’ is the
activation of the MIRROR NEURON SYSTEM
Humans
• Survival and success depends on ability to
thrive in complex social situations
• Our ability to understand the feelings and/or
actions of others
• Derived from neural mechanisms that allow us to
experientially comprehend actions and emotions of
others as well as mimic them
• Conceptual reasoning is NOT the fundamental
mechanism in understanding others
• Understanding ACTION and EMOTION
Observer and the Observed
• The observer and the observed are the
SAME!
• Why? Because both are endowed with the
same brain-body system
• What does this mean? The brain has the
ability to relate the first and third person
experiences
• Example: Connecting “I do and I feel” to “He
does and he feels”
Action and Emotion
• Action
• Neural system responds both when we
execute a particular directed action AND
when we observe someone else performing
a similar action
• Emotion
• Similar mechanism to action understanding
that bridges the first and third person
experiences
The Neural Mechanism
• Action Understanding
• Producing meaning for the visual representation
• MIRROR NEURONS!
• Found in the ventral premotor cortex (area F5) of
macaque monkeys
• Same population of neurons responds when
monkey performs specific goal directed action and
when it observes another performing that same
action
• The action is understood because the observer
knows the outcome of the action
Evidence
• Evidence for motor involvement in
action understanding
• Experiment: Evaluate the activity of F5 mirror
neurons while monkeys understand the
meaning of the action, without access to the
visual features that trigger mirror neurons
(MN).
First Study
• MN tested in two conditions
• 1: Monkey could see ENTIRE action
• 2: Same action but hand/object interaction
blocked by screen
Data
• Condition One
• Condition Two
Data
Second Study
• F5 MN recorded when monkeys saw and heard executed
noisy actions, only saw, or only heard.
Results
• 15% of MN are responsive to
presentation of actions accompanied by
sounds also responded to the
presentation of the sound alone!
• Thus, ‘audiovisual MN’ represent actions
independently of whether these actions are
performed, heard or seen.
• Convincing?
Compared to Human Data
• Observation of actions performed by others
activates cortical motor representations
• MN system formed by cortical network make up
• Rostral part of inferior parietal lobule
• Caudal sector of inferior frontal gyrus
• Adjacent part of pre-motor cortex
Human MN System
• Responds to wider range of actions
• Presence of object appears to be necessary
to MN activation in monkeys, but mimed
actions suffice to cause firing in human
system
• Motor evoked potentials are faciliated when
individual observes meaningless hand
gestures as well as when a transitive action
is observed
Summary Thus Far
• Concurrent activation of similar parts of
the motor system when we perform and
when we observe a particular action
• Actions are understood by having the
ability to mimic them and know the
purpose of the action
Emotion Understanding
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
• Mirror neurons as
the mechanism by
which we
understand the
actions of others
• Are others’ emotions
understood the same
way?
• Yes, via neurons in
the insula
• Disgust
Monkey Data
• Monkey insula divided into two main
subdivisions
• Anterior (visceral) Sector
• Multimodal Posterior Sector
• Anterior Sector receives input from:
• Olfactory and Gustatory centers
• Anterior sectors of ventral bank of superior
temporal sulcus
• Where there are neurons that respond to faces
Monkey Data
• In addition, insula receives interoceptive
afferents
• Stimulation causes viscero-motor
responses
Human Data
• Anterior insula activated by disgusting
olfactory and gustatory stimuli, as in
monkeys
• Also activated by disgusted facial
expressions
• Elicits viscero-motor responses
Insular Lesions
• Patient NK, “disgust deafness,” left insular
lesion
• Lack of response to visual and auditory stimulation
• Reduced experiential sensation
• Almost two standard deviations below normal
• Patient B, bilateral lesion
• Deficits in recognition of disgusted facial expressions
• Ingests food indiscriminately, even inedible items
fMRI Data
• Disgusting Odorants and Movie Clips
• Wicker et al, 2003
Neural structures associated with Disgust
• Areas involved in experience and the
perception of disgust.
• Insula
• Fundamental motor structures involved in
emotion expression and action control
• Anterior Cingulate Cortex (ACC)
• Basal Ganglia
Structures involved in the
empathy of pain
• Used FMRI to show that these
structures also mediate empathy for
pain
• Anterior Insula
• ACC
Towards a unifying neural hypothesis of the
basis of social cognition
• A bridge between ourselves and others
• The understanding of basic aspects of social cognition depends on
activation of neural structures normally involved in our own
personally experienced actions or emotions.
• Network of activation: Parietal and Premotor areas
• The ‘As If ’ Theory…
• Do we just see or hear an action or emotion?
• No, they postulated that side by side with the sensory descriptions of
the observed social stimuli, internal representations of the state
associated with these actions or emotions are evoked in the observer
‘as if” they were performing a similar action or experiencing a similar
emotion.
The Mirror Mechanism or ‘As if’
Theory
• According to their view:
• What is crucial for both the first and third person
comprehension of social behavior is the activation of the
cortical motor or visero-motor centers, the outcome of which,
when activating downstream centers, determines a specific
‘behavior’, be it an action or an emotional state.
• Further experiments…(Box 3)
• In favor of this theory, studies found that actions belonging
to the motor area of the observer (biting) are mapped on the
observer’s motor system
• Likewise, actions that do not belong to this area (barking) are
mapped out on the basis of their visual properties.
The Mirror Mechanism
• Social cognition is not only thinking about the
contents of someone else's mind…
• Our brains have developed a basic functional
mechanism ( mirror mechanism) which gives us
experiential insight into other minds.
• This mechanism provides the first unifying
perspective of the neural basis of social
cognition.
Problems with other theories of
understanding emotion
• Damasio and coworkers:
• “The feeling of emotions depends on the
activation of the somatosensory cortices in the
broader sense, and of the insula in particular.”
• Differs from the ‘as if’ theory presented by
authors, in regards to the underlying
neuromechanism.
• Authors indicate motor and viscero-motor centers as
central areas involved, not just the somatosensory area.
Discussion Questions
• Is the mirror system for actions and for
emotions, functioning normally in people with
autism, whose understanding of other minds
is impaired?
• No, they have observed abnormalities in the MNS
system as well as abnormalities in other areas in
the brain.
• Baby’s first steps
• http://www.youtube.com/watch?v=ua3P81gjdKg