mn Flashcards
MNS in monkeys and humans
In monkeys only for action understanding.
Monkeys do not imitate a lot! (A popular misunderstanding)
In humans for action understanding and imitation.
The MNS transforms visual information into knowledge by using one’s own motor repertoire and experience.
The motor theory of speech perception:
brain areas involved in producing speech also participate
when hearing spoken language.
Rizzolatti & Craighero (2004). Ann. Review Neuroscience
Rizzolatti & Sinigaglia (2010). Nature Rev. Neuroscience
Mukamel, Ekstrom, Kaplan, Iacoboni & Fried (2010
Recently single mirror neurons were recorded in human patients.
They found mirror neurons all over the place, about 10% of cells recorded throughout the brain had mirror neuron properties
TMS and MNS
Motor Evoked Potentials (MEPs) recorded from the hand are enhanced during observation of hand actions.
~ MEPs are selectively enhanced in those muscles used to produce the action observed.
~ Listening to words enhances MEPs in the receiver’s tongue.
Fadiga et al 1995
summary of mirror neurons in monkeys
Mirror neurons in premotor cortex (F5) and inferior parietal lobule (IPL), but not in Superior Temporal Sulcus (STS).
Eespond to the sight and sound of goal-directed actions and during their execution. May represent an abstract representation of the action and its goal/intention.
Goal-directed actions include: hand/object interactions, face movements, hand-to-mouth actions. The object needs to be present.
STS, Parietal cortex and F5 are directly connected.
Role in sensori-motor transformations.
Role in social cognition, mind/intention reading?
MNS components
direct connections between: STS (sight and sound - no motor neurons so no MN but neurons respond selectively to bodily actions); pre-motor cortex/F5 (motor, , sight. sound); and inferior parietal lobule/PF (sight, sound, motor)
umilta et al 2001
found evidence of MN activity when object was placed behind screen and action was not completed.
evidence of mn activity of hidden actions, leading people to interpret MNs are at core of action meaning.
kohler et al 2002
About 15% of mirror neurons responsive to the sight of an action also responded to the characteristic sound of that action
this supports the view that If mirror neurons mediate action understanding,
then their activity should reflect the meaning of the
observed action, not merely its visual features.
umilta et al 2008
reverse pliers experiment shows monkeys code for goal rather than the action
single neuron responses in monkeys
microelectrode lowered into brain andWhen the tip is close enough to a neuron, it picks up
the action-potentials (spikes) generated by that neuron
1. Mirror neurons respond during execution of goal-directed complex actions (e.g. grasping an object; i.e. transitive actions).2. However, they also respond to the sight of the same action, but not to the sight of other similar actions (strictly congruent neurons)!Broadly congruent neurons respond also to similar actions.
premotor cortex/ F5
Stimulation of a single neuron in pre-motor cortex causes coordinated movement in groups of muscles.
Produces complex actions such as grasping, holding or tearing, involving the coordination of many antagonistic muscles.
Importantly, these actions imply a goal. The premotor neurons do not simply code for a complex movement, but for a meaningful, goal-directed movement.
primary motor cortex/M1
Single neurons operate single muscles.
~ M1 is topographically arranged, neighbouring neurons activate neighbouring muscles.
~ Motor pathways are crossed:
left hemisphere moves muscles on the right side of the body,
right hemisphere moves muscles on the left side of the body,
