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57 Cards in this Set
- Front
- Back
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What areas are important for MNs? |
Primary motor Premotor cortex |
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What are the characteristics of M1 (primary motor) neurons? |
They operate a single muscle Topographically arranged - nearby neurons activate nearby muscles More representation for important areas |
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What are the characteristics of premotor neurons? |
They input to M1 cortical neurons Cause contraction to all the muscles connected to that cortical neuron Activity in one neuron can cause coordinated activity |
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Where were MNs originally found? |
The F5 of a monkey |
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Who first discovered MNs? |
Rizzolatti et al. (1996) |
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What did Rizzolatti et al. (1996) state about MNs? |
They are a special class of motor neurons Respond during the execution of goal-directed action and to the sight of the action |
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What are the properties of MNs? |
Action specificity Respond to face actions Motor, vision and audition Respond to hidden actions |
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Describe MNs action specificity |
Different ones represent different action They can be specific or broad |
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Describe how MNs respond to face actions |
They respond to the movement and the sight of the movement Things like sucking or lip-smacking |
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What is sucking in monkeys? |
An ingestive face movement |
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What is lip-smacking in monkeys? |
A communicative gesture |
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Describe the study which looked at motor, vision and audition MNs |
Kohler et al. (2002) Measured the response of two cells and the population in a monkey - Each cell was tested on vision, sound, motor and vision & sound Cell 1 - Peanut breaking vs. ring grasping (motor response is just to show that the cell responds to the peanut and not the ring) - Responded to the peanut from all types of MN and there was a super-additive response for sound & vision Cell 2 - Peanut breaking vs. paper ripping - Responded to the peanut from all types of MN and there was a super-additive response for sound & vision |
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Describe how MNs respond to hidden actions |
They respond to an action when the latter part is out of sight - Only if they know an object is being the screen |
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Do MNs respond to miming? |
No |
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What are the similarities and differences between miming and hidden actions? |
The visual stimuli is exactly the same The MNs can tell if it's goal-directed behaviour Their firing rate represents the monkeys understanding of the action outcome |
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Who tested whether MNs in monkeys code action goals? |
Umilta et al. (2008) |
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Umilta et al. (2008) Method |
Monkey pre-motor and M1 neuron response Trained them to associate action with an outcome - Moving hand to operate pliers to grab an object - Trained with normal and reverse pliers |
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Umilta et al. (2008) Results |
M1 neurons - Half responded to hand closure and half to opening - So they're coding the HAND MOVEMENTS Pre-motor neurons - All responded to either pliers - They're coding the ACTION GOAL |
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Umilta et al. (2008) Conclusions |
This pattern for grasping in pre-motor neurons transferred to tool use - The F5 neurons code the GOAL not the MOTOR action |
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Where else are MNs found in monkeys apart from the F5? |
Parietal cortex |
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What is another word for F5? |
The premotor cortex |
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Where is the intra-parietal sulcus? |
It runs through the middle of the parietal cortex |
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Where are the visual and visual & somatosensory MNs? |
Below the intra-parietal sulcus In the inferior parietal cortex |
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Who found evidence for MNs in the monkey parietal cortex? |
Fogassi et al. (2005) |
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Fogassi et al. (2005) Method |
Monkey starts with their hand on a button Phase 1 - Reaches out to grab an object/food - Identical actions Phase 2 - Puts it into mouth/container - Different actions based on goals |
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Fogassi et al. (2005) Results |
One MN had more response to grasping to eat - Didn't matter if it was edible or not - Didn't respond to placing food Another MN had more response to grasping to place - Responded in phase 1 only when phase 2 was appropriate |
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Fogassi et al. (2005) Conclusions |
MNs in the parietal cortex are coding the PURPOSE of the action They respond selectively before the action happens - they're predicting The MN firing rate shows the INTENTION of the monkey to perform a specific action, not the action itself |
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Fogassi et al. (2005) What was interesting/limiting of the design? |
The monkeys would repeat the same action - So they would expect them to eat |
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Summary |
The principal properties of MNs Areas of the brain which contains MNs (and which don't) The role of the MN system in action understanding How actions can be understood through a process of simulation |
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Which paper looks at MN circuits in humans and animals and how they tie into cognition? |
Rizzolatti & Sinigaglia (2010) |
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Rizzolatti & Sinigaglia (2010) - Overview |
The parieto-frontal cortical circuit has MN properties and is the only circuit that allows us to understand actions from the inside Discusses possible relevance for cognition |
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Rizzolatti & Sinigaglia (2010) Conclusions |
The motor-based understanding seen in the parieto-frontal circuit seems to be a major way of how we relate to each other Some evidence that the impairment of this link may be one of the causes of autism - They cannot relate to others |
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Which study looked at: Investigating action understanding: inferential processes vs. action simulation |
Brass et al. (2007) |
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Brass et al. (2007) Introduction |
We easily attribute goals and intentions to familiar actions We can also do this with unusual actions by using situational cues What mechanisms and neural processes are behind this ability? |
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Brass et al. (2007)
Two theories for action understanding |
Simulation theory - Understand other's actions by simulating behaviour internally - Mapping of action onto schema in the motor repertoire (using MNs) - Plausible for quick recognition of familiar goals Inference-based model - A goal is assigned to an action through evaluation of its efficiency as an optimal means of achieving the goal in the situation - Uses visual and context info - Related to brain areas without MNs - Plausible for unusual actions |
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Where is the human mirror system thought to consist of? Brass et al. (2007) |
Inferior frontal gyrus Inferior parietal cortex |
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Brass et al. (2007) Rationale |
Inference-based model may be used with just unusual actions but recent research shows it may be the basic understanding mechanism - Found in animals only - This study looks at the role of context |
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Brass et al. (2007)
Method and prediction |
15 p's saw unusual actions (light switch with knee) in 3 contexts - Plausible-constraint = hands occupied - Implausible-constraint = hands not too occupied to have to do that - No-constraint = hands free Prediction = Areas involved in intentional action in novel situation would have the most activation in the no-constraint, then implausible and then plausible. |
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Brass et al. (2007)
Results |
More activation in STS in no-constraint than plausible No difference between the 3 in the mirror system No difference between no-constraint and plausible in areas relating to the intentions of others |
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Brass et al. (2007)
Conclusions |
The data supports an inference-based account of action understanding in novel situations |
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Which study looks at: Grasping the intention of others with one's own MN system? |
Iacoboni et al. (2005) |
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Iacoboni et al. (2005)
Predictions |
If the MN system codes the type of action and its goal then activity in MN areas shouldn't be influenced by context If the MN system codes global intention associated with an observed action then context that cues the observer should modulate activity in MN areas |
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Iacoboni et al. (2005)
Stimuli |
Context - Series of objects (two types) - Drinking/cleaning Action - Grasp cup with no context (two types) - Precision/whole hand Intention - Shown in context condition - Grips intermixed |
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Iacoboni et al. (2005)
Methods |
23 p's with fMRI Implicit condition - Watched clips Explicit condition - Told to pay attention to the objects (context) and the type of grip (action) and work out the intention (context) |
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Iacoboni et al. (2005)
Results |
More activation in all 3 conditions compared to at rest Difference between intention condition compared to action and context conditions in MN areas |
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Iacoboni et al. (2005)
Discussion |
MNs code for intention as well as recognition Different activity between drinking and cleaning - Graspable objects in both To assign an intention is to infer a new goal, and this is done by the mirror system automatically |
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What does Iacoboni et al. (2005) show that has not been shown in monkey studies previously? |
MNs code for intention and not only recognition |
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Which study looked at: An interference effect of observed BM on action? |
Kilner et al. (2003) |
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Kilner et al. (2003) Aims & hypothesis |
If the motorsystem is ready to execute observed movements, there may be interference whenthe observed movement is qualitatively different from the simultaneouslyexecuted movement
Hypothesis = Interference should happen when an observed movement is qualitatively differentfrom a simultaneously executed movement |
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Kilner et al. (2003) Methods |
8 p's made repetitive movements with arm whilst observing a congruent/incongruent action - Executed movement - Congruency between observed and executed - Observed movement Actions done with human/robot to test if they are specific to BM movements Variance in movement used as a measure of interference |
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Kilner et al. (2003) Results |
Significant effects for: - Movement direction (more variation in horizontal) - Movement congruency (more variation in incongruent) - Observed effector - More variation in human Significant interactions for: - Observed effector and movement congruency (incongruent) |
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Kilner et al. (2003) Discussion |
Only interference for BM - So BM and non-BM are processed differently - Premotor cortex MNs distinguish between actions made by hands/tools Supports the MN system - Observation primes execution and causes interference when there is incongruence - MN's evolved at a small but significant cost to motor control |
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Kilner et al. (2003) What is good about using robots in their study? |
Shows the effects aren't due to increased attentional demands or task complexity |
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Which study looks at the problems with the MN theory of understanding actions? |
Hickok (2009) |
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Hickok (2009) Overview |
It has been argued that data from monkey studies shows MNs provide the basis of action understanding Here they argue there is no evidence to directly test this and that evidence from humans actually goes against this |
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What are some of the 8 problems with the MN theory of understanding actions presented in Hickok (2009)? |
1. No evidence in monkeys that MNs support action understanding 2. Action understanding can be done via non MN mechanisms 3. Relation between monkey MNs and the human mirror system is nonparallel/undetermined 4. Damage to the Inferior Frontal Gyrus isn't correlated with action understanding deficits 5. Generalisation of the mirror system to speech recognition fails on empirical grounds |
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Hickok (2009) Conclusions |
There are many goals that can be associated with an action and many actions that can be associated with a goal. So it isn't clear how MNs work |
