ZHAW 6, APRIL, 2016 WHAT DO NEURONS AND CORALS HAVE IN COMMON?

Transcription

1 ZHAW 6, APRIL, 2016 WHAT DO NEURONS AND CORALS HAVE IN COMMON?

2 YIHWA KIM ABOUT MYSELF Origin: Daegu, South Korea Countries stayed: Korea (most of the life), Japan (Okinawa: 3.5 years), Switzerland (Bern: 3.5 years, Lausanne: 4 years)

3 PROJECTS I HAVE WORKED ON Uni Bern, Bern, Switzerland OIST, Okinawa, Japan EPFL, Lausanne, Switzerland

4 PROJECT I WILL WORK ON AT ZHAW Group of Prof. Dr. Thomas Ott Forecasting of sales in supply chain using machine learning methods

5 TEXT DIVERSITY OF DENDRITIC MORPHOLOGIES OF THE NEURONS Ramon y Cajal

6 TEXT COMPLEX 3D MORPHOLOGY OF A NEURON downloaded from

7 cell type :2, cell: 1 a single bifurcation Daughter 1 reconstructed cells were obtained from Neuromorpho database Bifurcation point Daughter 2 A measure of geometrical property of a single bifurcation Parent

8 Cone angles Bifurcation point cone angle (Uylings & Smit 1975) Parent Daughter2 Daughter1

9 Planar structure in the local branches Planarity appears as a peak at 180 o Cone angle (Uylings & Smit 1975) visual cortex pyramidal cells of the rabbits (L2,3,4) Explanation : Tension or forced equilibria (Uylings & Van Pelt 2002)

10 P(α) = 3 4 sin3 α 2

11 Can the planar bifurcations be explained by the null distribution of random bifurcations?

12 Random bifurcations have highest chance to be planar, but this is not so pronounced as the experimental data.

13 Difficulty of finding an exact solution for wiring cost optimized tree Cost function might depend on: Volume (Cherniak, 1992), Surface area, Conduction speed (Chklovskii & Stepanyants 2003), Maximization of connectivity repertoire (Wen et al. 2009), Flow across a bifurcation (Uylings & Van Pelt 2002), path length, total wire length (Cuntz et al. 2007)... Some cost functions might act against each other e.g. volume vs. delay e.g. path length to soma vs. total wire length Most of them increase with length.

14 υ b υ p υ bʹ

15 We can always reduce the cost by flattening the bifurcation. Therefore all the bifurcations that are part of wiring cost optimized tree should be planar. Flat bifurcations are a necessary condition for wiring cost optimized tree. However it is not a sufficient condition for wiring cost optimized tree.

16 How about corals?

17 Cone angle bifurcations (corals)

18 %

19 Angle between two consecutive planes approximate a uniform distr. Purkinje cells: the symmetry breaking is induced by the orientation of the parallel fibers. M.mirabilis: geometrically exceptional within the genus Madracis as a result of unusually regular branching pattern (Filatov et al. 2010)

20 Neurons Corals

21 Big funded brain research projects world wide Human brain project (HBP) : EU Brain activity map project : Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative : US Human connectome project (HCP) : US Allen brain institute : US

22 Big brain simulations Blue brain project: Switzerland : creating a synthetic model of whole rat brain Riken K: Japan Largest neuronal network simulation so far (8/2013) Brain corporation : USA etc.

23 BBP and HBP Blue brain project (BBP) : swiss-led project hosted by EPFL : Making a detailed biophysical model of rat brain Human brain project (HBP) : Selected as a EU Future and Emerging Technology (FET) Flagship Initiative in Jan : Neuroscience + Medicine + Future

24 Blue brain project

25 TEXT

26 Need It is necessary to generate a large number of artificial neuron morphology in order to meet the demands of a big number of neurons needed for large scale simulation in blue brain project 56 X 10 6 neurons in Rat brain Currently reconstructed cells in the lab: 6 X 10 2 Human reconstructions of cells are time consuming, and the data are not always readily available.

27 AXON GENERATION STEPS

28 TEXT

29

30 SCOPE VPM neuron Cortical pyramidal cell axons Thalamocortical neuron axons