Transcript Mirror Neurons

Mirror Neurons
Irene Losa Aguado
Elena Domingo Calvete
Kaitlyn McNabb
Maddison Norton
Emily Stevens
Discovery of Mirror Neurons
• Discovered in the 1980s and 1990s
• Discovered by Giuseppe Di Pellegrino, Luciano
Fadiga, Leonardo Fogassi, and Vittorio Gallese
who worked at the University of Parma in Italy.
What is a Mirror Neuron?
• A neuron that fires when
• An animal performs an action
• The animal observes the same action performed by
another
• Thus, the neuron “mirrors” the behavior of the other, as
though the observer were performing the task.
• Directly observed in primate species
• Birds
• Imitative resonance behaviors
• Form of mirroring system
Development
• Human infant data using eye-tracking measures
suggest that the mirror neuron system develops before
12 months of age.
• This system may help human infants understand
other people's actions.
• A critical question concerns how mirror neurons
acquire mirror properties.
Development
• It’s unclear how newborn babies are able to mimic
the facial gestures of another person.
• One possibility is that the
sight of tongue protrusion
recruits an innate releasing
mechanism in neonates.
Brain Areas Composed of Mirror
Neurons
Premotor Cortex
• Location:
• Frontal Lobe
• Supplementary Motor Cortex
• Active immediately before movement
• Receives information about the target to which the body is
directing its movement and information about the body’s
current position and posture (Kalat, 2013).
Brain Areas Composed of Mirror
Neurons
Supplementary Motor Cortex
• Location:
• Frontal Lobe
• Active during preparation of a rapid sequence of movements
Inferior Parietal Lobe
• Location:
• Lower part of Postcentral Gyrus
• Perception of emotions in facial stimuli
• Interpretation of sensory information
Brain Areas Composed of Mirror
Neurons
Primary Somatosensory Cortex
• Location:
• Parietal Lobe
• Postcentral Gyrus
• Receives sensations from:
• Touch receptors
• Muscle-stretch receptors
• Joint receptors
Gender Differences
• Yawei Cheng
• Neurophysiological measures:
• MEG
• Spinal Reflex Excitability
• Electroencephalography
• Presence of gender differences:
• Female participants exhibit stronger motor
resonance than men participants
Gender Differences
• Emotional social interactions:
• Better empathetic ability in females compared to
males
• Females have greater ability in emotional
perspective taking than do males in face-to-face
interactions.
• Recognizing emotions
• Male and female ability is similar
Mirror Neurons in Monkeys
• Macaque monkey
• Mirror neurons are found in the inferior frontal gyrus and the
inferior parietal lobe.
• They found that some of the neurons they recorded from
would respond when the monkey saw a person pick up a
piece of food as well as when the monkey picked up the food.
*Infants can imitate a human’s face movements*
Article from New York Times
• Other animals:
• Monkeys, apes, elephants, dolphins, and dogs.
• Rudimentary mirror neurons
• Humans, with their huge working memory, carry out far
more sophisticated imitations.
• Social emotions
• Guilt, shame, pride, embarrassment, disgust, and lust.
• Based on a uniquely human mirror neuron system
found in a part of the brain called the insula.
Comparison Between Human and
Monkey Mirror Neurons
• Both the human and monkey mirror neuron system
mediates the same function of understanding actions
completed by others and the intentions behind them.
• Infant monkeys and humans can imitate facial
gestures of other’s.
• Evidence that mirror neurons develop at an early
stage in both monkeys and humans
• Location of the mirror neurons within the brains of
monkeys and humans is slightly different.
Evolution
• Premotor Neurons
• Types types of training:
• Hebbian Learning
• Presynaptic cells are constantly activating
postsynaptic cells
• Associative Learning
• Association between two stimuli of a
behavior and a stimuli
Evolution
• Premotor neurons need to be trained in order
to acquire mirror properties.
• However, it is unclear how babies are able to
mimic the facial gestures of another person.
• The sight of tongue protrusion recruits an
innate releasing mechanism in neonates.
Empathy
• Research on mirror neurons and “phantom limbs”
suggests an extraordinary human capacity for empathy.
• Example: (Marsh, 2012)
• Insular Cortex: Experience a painful sensation
• Anterior Cingulate: Cells respond to pain (agony)
• Fire when observing someone else being poked by
a needle
• Mirror neurons are most likely involved in empathy for
pain
Empathy Video
https://www.youtube.com/watch?v=Fl8Tc3qNhCc
Language
• fMRI studies found areas homologous to the monkey
mirror neuron system in the inferior frontal cortex,
proximal to Broca’s Area.
• Broca’s Area: Region of the brain associated with
language.
• Suggestion that human language evolved from a
gesture performance/understanding system
implemented in mirror neurons.
Language
• Mirror neurons have the potential to provide a
mechanism for:
• Action-understanding
• Imitation-learning
• Simulation of other people’s behavior
• New word pronunciation in children is linked to
mirror neurons
• Speech repetition occurs automatically, fast, and
separately in the brain to speech perception.
Language
• Brain activity of two participants was measured
using fMRI while they were gesturing words to
each other.
• Analysis of data using the Granger Causality
• Supported the idea that the motor concept
associated with words is transmitted from one
brain to another using the mirror neuron
system.
Motor Mimicry Video
https://www.youtube.com/watch?v=dVFKVCQPIjo
Imitation
• Two kinds of imitation:
• Automatic Imitation
• Mirror neuron system contributes to cognitive
functioning.
• Motor mimicry promotes prosocial attitudes and
behavior.
• Motor Mimicry
• Both depend on the same psychological and neural
processes.
• Both affected and controlled by the mirror neurons.
Theory of Mind
"Theory of mind" refers to our ability to infer
another person's mental state (i.e., beliefs and
desires) from experiences or their behavior.
Theory of Mind
According to simulation theory, theory of mind
is available because we subconsciously
empathize with the person we’re observing and,
accounting for relevant differences, imagine
what we would desire and believe in that
scenario.
Schizophrenia
Schizophrenia is a psychotic disorder in which personal,
social, and occupational functioning deteriorate as a result
of strange perceptions, unusual emotions, and motor
abnormalities (Comer, 2014).
• The discovery of “mirror neurons” provided an
understanding of social cognition at a cellular level
(Burns, 2006).
• The biological explanation of these abnormalities may be
explained by an abnormal functioning of the mirror
system (Burns, 2006).
Schizophrenia
• The imitation and observation of others’ actions is an
important component of social cognition, which is
altered in schizophrenia (McCormick, 2012).
• Processing of social and emotional information has
been shown to be disturbed in patients with
schizophrenia (McCormick, 2012).
• Mirror neuron system forms the basis for the
interpersonal experience and provides a basis for
human empathy (McCormick, 2012).
Schizophrenia
• One of the main barriers to recovery for many people
with schizophrenia are their profound and enduring
difficulties with social interactions.
• Experience great difficulty forming relationships and
maintaining employment
• Social impairments manifest in several different
ways, ranging from paranoia of people intending to
hurt them to withdrawing completely from social
interactions.
Mirror Neurons Linked to
Schizophrenia
• Neuroscientists at Vanderbilt University
• Supported theory that an impaired ability to
imitate may underline the profound difficulty with
social interactions that characterize schizophrenia.
• American Journal of Psychiatry
• Researchers reported that people who were asked
to imitate simple hand movements exhibited
abnormal brain activity in areas associated with
the ability to imitate (Salisbury).
Study
“The fact that patients with schizophrenia show
abnormal brain activity when they imitate simple hand
gestures is significant because action imitation is a
primary building block of social abilities”.
• Katherine Thakkar
• The ability to imitate is present early in life and is
crucial for learning how to navigate within the social
world.
Study
• Functional Magnetic Resonance Imagining (fMRI): Maps
levels of brain activity by measuring associated changes in
the blood flow.
• The study uses fMRI to examine the brain activity of
schizophrenic patients while they perform basic imitation
tasks.
• Performed on sixteen medicated schizophrenic patients and
sixteen healthy participants
• Confirmed that patients with schizophrenia have an
impaired ability to imitate.
Autism
Autism Spectrum Disorder (ASD) is a severe
neurodevelopmental disorder that is characterized by extreme
unresponsiveness to people, severe communication deficits,
and rigid and repetitive behaviors, interests, and activities
(Comer, 2014).
• Symptoms:
• Lack of social skills
• Absence of empathy
• Language deficits
• Poor imitation
• Dysfunction of mirror neuron system in individuals
diagnosed with autism.
The Mirror Neuron Revolution: Explaining
What Makes Humans Social
• Marco Iacoboni (Lehrer, 2008).
• Mirror neuron dysfunction has been associated
with:
• Social Deficits
• Difficult time understanding mental states of
others
• Motor Deficits
• Language Deficits
The Anatomy of Autism
Inferior Frontal Gyrus
• Reduced mirror neuron activity
• Inability to assess intensions of others
Insula & Anterior Cingulate
• Dysfunction of mirror neurons
• Cause related symptoms (absence of empathy)
Angular Gyrus
• Deficits that result in language difficulties
• Structural changes in brain stem and cerebellum
The Anatomy of Autism
Mirror Neuron Dysfunction in
Children with Autism
• Electroencephalogram (EEG): Measure brain waves
• Mu wave: Blocked when a person watches
someone else perform the same action
• Study: (Ramachandran & Oberman, 2006)
• High-functioning children with autism
• Monitored mu waves as they made voluntary
muscle movements and then watched the same
actions on video.
Mirror Neuron Dysfunction in
Children with Autism
• Results:
• Mu wave suppressed when completing a voluntary
muscle movement
• Mu wave showed no suppression when watching
someone else perform the action.
Video
https://www.youtube.com/watch?v=_8WV1zAh9zU
References
Blakeslee, Sandra. “Cells that Read Minds.” The New York Times. The New York Times
Company, 10 Jan. 2006. Web. 19 April 2015,
www.nytimes.com/2006/01/10/science/10mirr.html.
Burns, J. (2006). The social brain hypothesis of schizophrenia. World Psychiatry.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1525115/
Comer, R. (2014). Abnormal Psychology. (8th ed.) New York, NY: Worth Publishers.
Kalat, J. (2013). Biological Psychology. (11th ed.) Belmont, CA: Wadsworth.
Lehrer, J. “The Mirror Neuron Revolution: Explaining What Makes Humans Social.”
Scientific American. 1 July 2008. Web. 19 April 2015,
http://www.scientificamerican.com/article/the-mirror-neuron-revolut/.
Marsh, J. (2012). “Do Mirror Neurons Give Us Empathy”. Greater Good Science Center.
Web. 11. Apr. 2015,
http://greatergood.berkeley.edu/article/item_mirror_neurons_give_empathy.
References
McCormick, LM.. (2012). Mirror neuron function, psychosis, and empathy in
schizophrenia. NCBI Web:
http://www.ncbi.nlm.nih.gov/pubmed/22510432.
Meltzoff, A.N. (2005). Imitation and other minds: The “Like Me” Hypothesis. In S.
Hurley and N. Chater (Eds.), Perspectives on Imitation: From Neuroscience to
Social Science. (Vol. 2), 55-77. Cambridge, MA: MIT Press.
“Mirror Neurons.” Wikipedia. Wikimedia Foundation, Jan. 2015. Web. 11. Apr.
2015, http://en.wikipedia.org/wiki/Mirror_neuron.
Ramachandran, V.S. & Oberman, L.M. (2006). “Broken Mirrors”. Scientific American
Inc. Web. 12. 2015. Retrieved from:
http://cbc.ucsd.edu/pdf/brokenmirrors_asd.pdf.
Salisbury, David. “Brain Mapping Confirms Patients with Schizophrenia Have
Impaired Ability to Imitate.”Vanderbilt Research. Vanderbilt University, n.d.
Web. 10 Apr. 2015,
http://news.vanderbilt.edu/2014/03/schizophrenia-imitation.