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What are Mirror Neurons? Mirror neurons are cells that fire when a monkey (or person?) performs an action or when it views another animal performing that.

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Presentation on theme: "What are Mirror Neurons? Mirror neurons are cells that fire when a monkey (or person?) performs an action or when it views another animal performing that."— Presentation transcript:

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2 What are Mirror Neurons? Mirror neurons are cells that fire when a monkey (or person?) performs an action or when it views another animal performing that same action

3 What are Mirror Neurons? Located in conjunction with a frontoparietal action planning network: – posterior inferior frontal pre-motor areas that represent impending actions Many cells are “motor dominant”: they fire when monkey grasps or reaches, but are independent of visual input – inferior parietal sensory area that integrates somatosensory, visual and auditory signals Many cells are “visuo-dominant” or “visuomotor-dominant”: they fire when monkey sees a graspable object or a stimulus that could be interacted with – These regions are densely interconnected

4 What are Mirror Neurons? Mirror neurons are in regions immediately adjacent to these frontal and parietal areas Motor properties of mirror neurons are same as “non- mirror” neurons but… Sensory properties are different – These cells do not fire when monkey sees a graspable object – They do fire when monkey sees another monkey (or a person!) perform actions relative to objects

5 What can Mirror Neurons Represent? Some cells are precisely tuned to the specific actions – e.g. using two fingers to pick up an object Others are broadly tuned to any action that accomplishes the same goal – E.g. using any combination of hand and fingers to pick up an object

6 What can Mirror Neurons Represent? Mirror neurons represent abstract actions and goals – Cells will not fire when grasping is pantomimed – Cells will fire when grasping is real and visible – Cells will also fire when grasping happens behind an occluding screen, as long as the monkey has seen that there is an object to be grasped behind the screen!

7 What can Mirror Neurons Represent? Mirror neurons represent abstract actions and goals – Some mirror neurons will even fire in response to the sound of an action being performed e.g. the sound of breaking a peanut shell

8 What can Mirror Neurons Represent? Mirror neurons represent intended actions – Some cells fire more when monkey grasps food with intention to eat it – or when monkey observes a human grasping food to eat it – Some cells fire more when monkey grasps food with intention to place it in a container – or when monkey observes a human placing food in a container

9 Mirror Neurons in Humans? The existence of mirror neurons in humans is inferred – We don’t record directly from human cortex!

10 Mirror Neurons in Humans? fMRI studies have found evidence for two brain regions associated with imitative actions Task 1: watch action Task 2: perform action Task 3: imitate action

11 Mirror Neurons in Humans? Based on work with monkeys, it was presumed that mirror neuron areas would exhibit a specific pattern of BOLD response: Task 1 < Task 2 < Task 3 Two regions exhibited such a response

12 Mirror Neurons in Humans? Mirror Neuron System (MNS) in Humans seems to be part of a system that mediates empathy fMRI data revealed MNS areas plus limbic areas became activated during observation of emotional faces – MNS areas became more activated during imitation of an emotional facial expression

13 Mirror Neurons Dysfunction in Autism? Some evidence supports a theory (speculation?) that a dysfunction of the MNS underlies social isolation disorders such as autism spectrum disorder (ASD) – Some structural abnormalities – MEG data shows abnormal propagation of signals in the MNS when imitating lip movements in individuals with Asperger’s Syndrome – fMRI data shows that BOLD signal in MNS during viewing and imitating emotional expressions is negatively correlated with severity of Autism Spectrum Disorder


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