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Lecture Overview

Lecture Overview. Regier System: Limitations Image Schemas: Recap Force Dynamic Schemas: Recap Sensory-Motor Schemas Evidence in Primates Evidence in Humans Do motor schemas play a role in language? A Computational Model of Motor Schemas Learning Hand Action terms (Bailey)

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Lecture Overview

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  1. Lecture Overview • Regier System: Limitations • Image Schemas: Recap • Force Dynamic Schemas: Recap • Sensory-Motor Schemas • Evidence in Primates • Evidence in Humans • Do motor schemas play a role in language? • A Computational Model of Motor Schemas • Learning Hand Action terms (Bailey) • Cultural Schemas and frames

  2. Limitations • Scale • Uniqueness/Plausibility • Grammar • Abstract Concepts • Inference • Representation

  3. Force Dynamics, modals and causatives • A gust of wind made the pages of my book turn. • The appearance of the headmaster madethe pupils calm down. • The breaking of the dam let the water flow from the storage lake. • The abating of the wind let the sailboat slow down.

  4. Schematic Representation(Talmy)

  5. FD Patterns • A gust of wind made the pages of my book turn. • The appearance of the headmaster made the pupils calm down. • The breaking of the dam let the water flow from the storage lake. • The abating of the wind let the sailboat slow down.

  6. Closed Class vs. Open Class terms • Image Schematic and Force Dynamic Patterns are expressed by closed class terms in language • Prepositions (in, on, into, out) • Modals and causatives (make, let, might, prevent) • How about open class terms? • Verbs and Event descriptions – • Motor Schemas - Embodied • Is there evidence for motor schemas and if so are they used in language? • Frames – Composed from Image and motor schemas -Cultural

  7. Coordination • PATTERN GENERATORS, separate neural networks that control each limb, can interact in different ways to produce various gaits. • In ambling (top) the animal must move the fore and hind leg of one flank in parallel. • Trotting (middle) requires movement of diagonal limbs (front right and back left, or front left and back right) in unison. • Galloping (bottom) involves the forelegs, and then the hind legs, acting together

  8. Sensory-Motor Schemas • A sensory (perceptual) schemadetermines whether a given situation is present in the environment. • Object Detection • Spatial relation recognition • Execution of current plans is made up of motor schemaswhich are akin to control systems but distinguished by the fact that they can be combined to form coordinated control programs • Sensory and Motor Schemas are closely coupled circuits sensory-motor schemas.

  9. The neural theory Human concepts are embodied. Many concepts make direct use of the sensory-motor capacities of our body-brain system. • Many of these capacities are also present in non-human primates. • Let us look at concepts that make use of our sensory-motor capacities, ex. Grasp.

  10. Area F5 General Purpose Neurons: General Grasping General Holding General Manipulating

  11. General Purpose Neurons in Area F5 A Grasping with the mouth B Grasping with the cl. hand C Grasping with the ipsil. hand (Rizzolatti et al. 1988)

  12. General Purpose Neurons Achieve Partial Universality: Their firing correlates with a goal-oriented action of a general type, regardless of effector or manner.

  13. Area F5c Convexity region of F5: Mirror neurons

  14. F5c-PF Rizzolatti et al. 1998

  15. Strictly congruent mirror neurons (~30%) Observed Action Executed Action Executed Action (Rizzolatti et al. Cog Brain Res 1996)

  16. Category Loosening in Mirror Neurons (~60%) (Gallese et al. Brain 1996) A [C] is Observe (Execute) Precision Grip (Prototype) B [D] is Observe (Execute) Whole Hand Pre-hension

  17. The F5c-PF circuit Links premotor area F5c and parietal area PF (or 7b). Contains mirror neurons. Mirror neurons discharge when: Subject (a monkey) performs various types of goal-related hand actions and when: Subject observes another individual performing similar kinds of actions

  18. Phases Area F5 contains clusters of neurons that control distinct phases of grasping: opening fingers, closing fingers. Jeannerod, et al., 1995; Rizzolatti, et al., 2001.

  19. Mirror Neurons Achieve Partial Universality, since they code an action regardless of agent, patient, modality (action/observation/hearing), manner, location. Partial Role Structure, since they code an agent role and a purpose role. The Agent Role: In acting, the Subject is an agent of that action. In observing, the Subject identifies the agent of the action as having the same roleas he has when he is acting – namely, the agent role. The Purpose Role: Mirror neurons fire only for purposeful actions.

  20. Mirror Neurons Achieve Category tightening and loosening

  21. The F4-VIP circuit

  22. The F4-VIP Circuit Links premotor area F4 and parietal area VIP. Transforms the spatial position of objects in peri-personal space into motor programs for interacting with those objects. Examples: Reaching for the objects, or moving away from them with various parts of your body such as the arm or head.

  23. Area F4 Arm reaching Head turning

  24. Somato-Centered Bimodal RFs in area F4 (Fogassi et al. 1996)

  25. Somato-Centered Bimodal RFs in area VIP (Colby and Goldberg 1999)

  26. AIP and F5 (Grasping) in Monkey AIP - grasp affordances in parietal cortex Hideo Sakata F5 - grasp commands in premotor cortex Giacomo Rizzolatti

  27. Size Specificity in a Single AIP Cell • This cell is selective toward small objects, somewhat independent of object type ( Hideo Sakata) • Note: Some cells show size specificity; others do not.

  28. Summary of Fronto-Parietal Circuits Motor-Premotor/Parietal Circuits PMv (F5ab) – AIP Circuit “grasp” neurons – fire in relation to movements of hand prehension necessary to grasp object F4 (PMC) (behind arcuate) – VIP Circuit transforming peri-personal space coordinates so can move toward objects PMv (F5c) – PF Circuit F5c different mirror circuits for grasping, placing or manipulating object Together suggest cognitive representation of the grasp, active in action imitation and action recognition

  29. MULTI-MODAL INTEGRATION The premotor and parietal areas, rather than having separate and independent functions, are neurally integrated not only to control action, but also to serve the function of constructing an integrated representation of: Actions, together with objects acted on, and locations toward which actions are directed. In these circuits sensory inputs are transformed in order to accomplish not only motor but also cognitive tasks, such as space perception and action understanding.

  30. Modeling Motor Schemas • Relevant requirements (Stromberg, Latash, Kandel, Arbib, Jeannerod, Rizzolatti) • Should model coordinated, distributed, parameterized control programs required for motor action and perception. • Should be an active structure. • Should be able to model concurrent actions and interrupts. • Should model hierarchical control (higher level motor centers to muscle extensor/flexors. • Computational model called x-schemas (http://www.icsi.berkeley.edu/NTL)

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