Motor cortical areas: the homunculus The motor system

Major Cortical areas involved in planning and execution of “purposeful” movements

Directional Tuning of MI Cells Movement onset (Georgopoulos et al 1982) P.D.

Set related responses in Pre-motor Cortex Prepare LEFT movementPrepare RIGHT movement

Mirror neurons Rizzolatti et al., 1996

Basic properties of the Mirror Neurons Rizzolatti et al. 1996

A multimodal representation of action

Mirror neurons in the Parietal cortex: Intention understanding?

Mirror neurons show the same specificity when actions are preformed by the experimenter

What is represented by the MN? Actions or goals? Hand unit210unit199 Umlita et al., 2008 closure opening

The mirror system – abstract representation of movement goals? Recordings from 37 mirror neurons in F5 in a “hidden action” paradigm 19/37 mirror neurons responded significantly in the hidden condition. 7/19 – strong responses (hidden=visual) (Umilta et al., 2001). Full vision Hidden vision

The mirror system in humans

Cortical activation during observation of mouth hand and foot action

Shmuelof & Zohary 2006 Viewed-Hand identity effects in parietal cortex

Visual and motor hand areas in the human parietal cortex

Specificity of visually defined “hand areas” to motor actions

Functional role of the MN Communication Imitation

Mirror system: imitation? Animated hand Static hand X position

imitate Move X finger Move X finger The role of imitation Iacoboni et al., science 1999

A deeper understanding of “mirror like voxels”

Mirror neurons should show cross-modal adaptation Mirror regions should be active both during viewing action and motor action

Right anterior parietal cx Observation based Action Observation only

Left frontal operculum BA 44 Observation based Action Observation only

Observation based Action Observation only Right parietal operculum

Functional role of the MN Intention/context

Mirror system in humans intention understanding: drinking or cleaning, compared to grasp only or context only fMRI scan of 23 human subjects (Iacoboni et al., 2005)

Functional role of the MN Communication Imitation Intention/context Social behavior

Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders ASD patients controls

Functional role of the MN Communication Imitation Intention/context Social behavior Language

The mirror system and the evolution of language F5 in monkeys corresponds anatomically (location and cytoarchitecture) to Broca’s area (specifically to the pars opercularis of IFG corresponding to area 44) Lateral F5 mirror neurons respond to mouth movements, some of them to communicative mouth movements Could the mirror system be the evolutionary basis for the development of language?,

(Hamzei et al., 2003) self grasping Viewed grasping Verb generation

(Hamzei et al., 2003) action recognition (active >passive) language production (verb > rest2 (

Language within our grasp? Not yet… But: –a mirror system exists and probably enables understanding of actions (in primates too) –This mirror system can also infer actions that are not directly seen, and can infer intention –This forms a good basis for the development of language from hand and face expressions not directly connected to their instructed meaning –Therefore, the mirror system could be the neurological basis for the development of language