1 / 36

E-mail: witali.duninbarkowski@ttuhsc

E-mail: witali.duninbarkowski@ttuhsc.edu. Great Brain Discoveries: When White Spots Disappear?. Witali L. Dunin-Barkowski, Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia Department of Physiology, TTU Health Sciences Center, Lubbock, Texas, USA.

ivi
Download Presentation

E-mail: witali.duninbarkowski@ttuhsc

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. E-mail: witali.duninbarkowski@ttuhsc.edu Great Brain Discoveries: When White Spots Disappear? Witali L. Dunin-Barkowski, Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia Department of Physiology, TTU Health Sciences Center, Lubbock, Texas, USA ACAT’2002, Moscow, Russia, June 24-28, 2002

  2. http://www.physiology.ttuhsc.edu/wldb/Witali/Witali.htm ? ? Knowledge: Finite or Infinite = = Universe: Open or Closed Understanding Brain: Fascinating but Finite Problem The best known precedent: Walking Simpler Problem: Flying

  3. Exponential Growth in a Limited Space Microbes in a Jar Task formulation: A microbe divides in two in a second (Tm=1 s). At the start of experiment (T(0)=0) there is one microbe in the 3 liter jar. In Tf=24 hours the jar will be filled with the microbes. Q.: How much time it would take to fill 1/2 of the jar? 1/1000 of the jar? A.: T(J/2)=24 hrs- 1 s; T(J/1000)=24hrs-10 s

  4. Understanding Brain: Finding a Time Constant Society for Neuroscience Annual Meetings Number of Attendees (1970 - 2001)

  5. http://www.physiology.ttuhsc.edu/wldb Neural Mechanics: The First Two Uncovered Mechanisms 1. Sensory Cortex 2. The Cerebellum

  6. Understanding the Brain: Role of John Hopfield In 1982-1984 he has discovered NEUROMAGNETICS New Hopfield's Paradigm in Computational Neuroscience 1. J.J. Hopfield, C.D. Brody Proc. Nat. Acad. Sci., Vol. 97, No. 25, pp. 13919-13924, Dec., 2000. 2. J.J. Hopfield, C.D. Brody Proc. Nat. Acad. Sci., Vol. 98, No. 3, pp. 1282-1287, Jan., 2001.

  7. Hopfield’s paper animal (HPA)

  8. HPA

  9. HPA: Mechanisms

  10. HPA: experimental verification Hopfield & Brody, 2001, Fig. 9 Dunin-Barkowski W.L., Lovering A.T., Orem J.M., Vidruk E.T., Sirota M.G., Beloozerova I.N. Submitted to Computational Neuroscience Meeting, Chicago, July, 2002

  11. http://www.physiology.ttuhsc.edu/wldb THE CEREBELLUM: 10 % OF THE BRAIN MASS 90 % OF BRAIN NEURONS ? % OF UNIQUE BRAIN FUNCTIONS DETAILS ONLY: You CAN live without cerebellum

  12. Mauk’s Equations (esp. (2) and (4)) (1) (2) (2`) (3) (4)

  13. How equalization works Total synaptic inflow to climbing fiber cell (1), synaptic inflow from extra-cerebellar sources (2), and climbing fiber cell impulses (3) in a transient state of (left) and in the steady state (right). Density of climbing fiber cell firing vs. phase of template signal (1) - transient, (2) - steady states. Equalization is unstable when plasticity depends on ionotropics 1 and 2 as above; climbing fiber cell impulses are not shown: they are highly correlated with the phase of template signal all time. Red bar denotes short period of “attempted” equalization.

  14. “Intracellular” record of the membrane potential of the model climbing fiber cell

  15. Poincare plot of sequential intervals between CFC impulses

  16. Solution exists, whenM  N

  17. Minimal model: Mutual inhibition with accommodation Accommodation: hot topic [Hopfield & Brody, 2001] Respiratory Pattern Generator - is a first example of a physiological system, where the tentative physiological role of accommodation as a time-scale factor was first proposed [Reiss, 1964]. Underlying mechanisms: Ca++-dependent potassium conductance (proposed for RPG in [Rybak, Payton & Schwaber, 1997])

  18. Respiratory Rhythms: Network vs. Pacemaker Mechanisms.

  19. Intraneuronal Mechanisms and Muscle Contraction: Ryanodine Receptors Ca-dependent Ca release. Contraction demands large amounts of Ca. To make the process independent of extracellular Ca concentrations it is released from intracellular cisterns. A fast mediator is needed to transfer events at the membrane inside the cell. The most convenient substance - Ca. Just as a signal, not as a catalyzing substance.

  20. Ca-dependent K-channels: accommodation. Release of Ca from intracellular compartments produces cell inhibition. Three factors: (1) external excitation; (2) Ca-dependent K-channels; and (3) Ca- dependent Ca release acting in concert can provide both conditional pacemakers and flip-flop oscillations. Network mode of operation depends on a single parameter: strength of inhibitory connections between opposing neuron pools.

  21. Model 1 Model 2 In Vivo Dunin-Barkowski W.L., Escobar A. L., Lovering A.T., Orem J.M., Submitted to Soc. for Neuroscience Annual Meeting, Orlando, Florida, November, 2002

  22. Model 1 Model 2 Dunin-Barkowski W.L., Escobar A. L., Lovering A.T., Orem J.M., Submitted to Soc. for Neuroscience Annual Meeting, Orlando, Florida, November, 2002

  23. Understanding the Brain: Operational Tools We know a lot about the components We should also keep searching for new components and their combinations The work is demanding and rewarding: We reveal ourselves. The final results are soon to come. Although, may be not so soon, as one could hope:

  24. 23 y. < Tfin < 91 y.

More Related