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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) Set related responses in Pre-motor Cortex Prepare LEFT movement Prepare 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? unit210 opening Hand Umlita et al., 2008 closure unit199 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) Full vision Hidden vision (Umilta et al., 2001). The mirror system in humans Cortical activation during observation of mouth hand and foot action Viewed-Hand identity effects in parietal cortex Shmuelof & Zohary 2006 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 The role of imitation imitate Move X finger Move X finger Iacoboni et al., science 1999 A deeper understanding of “mirror like voxels” Mirror regions should be active both during viewing action and motor action Mirror neurons should show cross-modal adaptation Observation based Observation Action only Right anterior parietal cx Observation based Observation Action only Left frontal operculum BA 44 Observation based Observation Action 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 controls ASD patients Understanding emotions in others: mirror neuron dysfunction in children with autism spectrum disorders 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? , self grasping Viewed grasping (Hamzei et al., 2003) Verb generation action recognition (active >passive) language production (verb > rest2 ( (Hamzei et al., 2003) 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