1 / 80

ONLY CONNECT

ONLY CONNECT. David Willshaw Institute for Adaptive & Neural Computation School of Informatics University of Edinburgh willshaw@inf.ed.ac.uk. ONLY CONNECT. Computational thought  Hamming Seminars Bell Labs  Radar  Family history Bell Labs  Information Theory My research.

alika
Télécharger la présentation

ONLY CONNECT

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ONLY CONNECT David Willshaw Institute for Adaptive & Neural Computation School of Informatics University of Edinburgh willshaw@inf.ed.ac.uk

  2. ONLY CONNECT Computational thought  Hamming Seminars Bell Labs  Radar  Family history Bell Labs Information Theory My research

  3. ONLY CONNECT Only connect ! That was all her sermon. Only connect the pride and the passion and both will be exalted, and human love will be seen at its height. Live in fragments no longer. Only connect..... From Howard’s End by E M Forster

  4. This is my research area: COMPUTATIONAL MODELLING OF THE DEVELOPMENT OF NEURAL CONNECTIVITY

  5. Why is this an important area? Why is this an important area now?

  6. Without the correct specific connectivity patterns between our neurons we cannot function correctly We don’t yet know the mechanisms for how the brain is wired up Computational modelling is used to explore particular hypotheses and suggest experiments to try to understand the underlying mechanisms New technologies are giving us much better data about connectivity

  7. Human Brain – MRI scan(Wellcome Images; Mark Lythgoe, Chloe Hutton) Cerebellum

  8. The cerebellar cortex contains nerve cells of several different types Cajal(1905)

  9. Purkinje cell (Wellcome Images; David Becker)

  10. Shows the Purkinje cells lined up and the parallel fibres (Cunningham, 1913)

  11. Purkinje cells and parallel fibres(Wellcome Images; Spike Walker)

  12. Vertebrate retina

  13. Vertebrate retina

  14. Visual pathways in mammals

  15. Ocular dominance columns The binocular projection from retina to cortex in mammals Zebra stripes? Reminiscent of Turing Patterns postulated to be formed in morphogenesis by mechanisms of reaction-diffusion AM Turing , Phil. Trans. Roy. Soc. B, 237, 37-52, 1952

  16. Computational modellingin neuroscience

  17. CNS Systems Maps Networks Neurons Synapses Molecules m 10 cm 1 cm 1 cm 100 m 1 m A

  18. Modelling at the nerve cell level(Wellcome Images; Benedict Campbell)

  19. 1952: The first computational neuroscience model A quantitative description of membrane current and its application to conduction and excitation in nerve. Hodgkin & Huxley, J Physiology (1952)

  20. The Hodgkin-Huxley modelImpulse propagation caused by flow of K+ and Na+ currents through separate channels in the membranePermeability to ion flow in these channels is dependent on the potential difference across the membrane

  21. Modelling a segment of the axon as an electrical circuit where the resistances are voltage dependent

  22. HH equations account for all the data

  23. A model at the network level

  24. Learning and Memory:Hebb’srule ‘When an axon of cell A is near enough to excite cell B or repeatedly or consistently take part in firing it, some growth or metabolic change takes place in one or both cells such that A’s efficiency, as one of the cells firing B, is increased.’ Hebb (1949)

  25. Hebb's rule and associative memory Distributed Memory: The Associative Net (Willshaw, Buneman & Longuet-Higgins, Nature, 1969) Clipped Hebbian rule

  26. Modelling of the development of nerve connections

  27. Polyneuronalinnervation in foetal human muscle (1917) J.F. Tello

  28. Connections between neonatal nerve and muscle(Wellcome Images, Ribchester & Gillingwater)

  29. Visual pathways in mammals

  30. FROG BRAIN CAT BRAIN

  31. Xenopus tadpoles

  32. Frogs and toads Xenopus

  33. Frog visual system

  34. What is the mechanism for the formation of ordered maps of nerve connections?Both flexibility and rigidity in connection pattern are seen - probably more than one mechanism act together? From Jacobson (1967)

  35. The main theories • Chemoaffinity– molecular cues guide each axon to its target cell or cells (usually associated with rigidity of connection) • Electrical signalling - e g, nearby cells that fire together may be more active than more distant cells and so can signal neighbour relations to the cells to which they are connected – usually associated with flexibility of connections.

  36. So what is the link with Informatics?

  37. “Informatics” means different things to different people? “When I use a word” Humpty Dumpty said rather in a scornful tone “It means what I choose it to mean –neither more nor less” Alice Through the Looking Glass, Lewis Carroll

  38. Computational Models Neural Engineering inspire new hardware and software methods Software Systems collect, analyze, archive, share, simulate and visualize data and models Neuroinformatics  INCF information-processing in the nervous system

  39. Neuroinformatics  INCF INCF – International Neuroinformatics Coordinating Facility (www.incf.org) An international organisation subscribed to by 15 governments Dedicated to the coordination of neuroinformatics world wide. Each country has its own local organisation; I am the UK Coordinator and scientific representative at INCF

  40. Mike Fourman’s formulation: “Informatics is the study of how natural and artificial systems store, process and communicate information”

  41. The School of Informatics at Edinburgh is inclusive rather than exclusive. ++: Aren’t we lucky to be not constrained!

  42. The School of Informatics at Edinburgh is inclusive rather than exclusive. ++: Cross-fertilisation --: Because of the breadth there is a danger that individuals have a lack of understanding of other fields of research practised in Informatics

  43. A snapshot, which I prepared for Mike Fourman, of the interactions between academic and research staff in the three departmental groupings in 1997, prior to the formation of the School of Informatics AI/AIAI: Artificial Intelligence/AI Applications Institute DCS: Department of Computer Science CCS/HCRC: Centre for Cognitive Science/Human Communications Research Centre

  44. The importance of technology in the computational modelling of the nervous system

  45. Julius Bernstein (1839-1917), after whom the Bernstein Centres for Computational Neuroscience in Germany are named. His membrane theory of the propagation of the nerve impulse (1902) was almost right.

  46. But his equipment for measuring the properties of the nerve impulse was inadequate

  47. Once Hodgkin had been to Chicago (50 years later) to learn how to build an amplifier, he and Huxley could collect, analyse and model the required data, leading to a Nobel Prize for them Alan Hodgkin Andrew Huxley

  48. My current research problem

  49. What is the mechanism for the formation of ordered maps of nerve connections?Both flexibility and rigidity in connection pattern are seen - probably more than one mechanism act together? From Jacobson (1967)

More Related