Speaker: Jimmy Lu Topics: Brain Network - Thalamocortical Motif Date: 2010.03.20 WECO Lab, CSIE, FJU

1. Brain Networks
Thalamocortical Motif
Speaker : Jimmy Lu
Advisor : Hsing Mei
Web Computing Laboratory(WECO Lab)
Computer Science and Information Engineering Department
Fu Jen Catholic University

2. Outline
 Report proposal
 Background and review
 Small-world network
 Scale-free network
 Reentrant mapping
 Links, issues, and opinions
 Future work
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3. Report Proposal
 Thalamocortical motif
 Polysynatic loop structure
 Diffuse ascending projection
 Cognitive science
 Social networks
 Collective intelligence
 Web intelligence
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4. Background and Review (1/3)
 Thalamus
 process sensory
information as well
as relaying it
 As a gateway, a
switch, or a relay
 Reticular nucleus,
intralaminar nuclei
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5. Background and Review (2/3)
 Cerebral cortex
 Brain map
 Plays a key role
in memory, attention,
perceptual awareness,
thought, language,
and consciousness
 Small-world, Scale-free
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6. Background and Review (3/3)
Thalamocortical radiations
 Reentrant mapping
 Sensory information
go through the spine
cord to the thalamus,
and then relay it to
the cortical areas
 Dynamic core
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7. Small-world network (1/7)
 The intermediate region between
regular and random
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8. Small-world network (2/7)
 Clustering coefficient and path length
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9. Small-world network (3/7)
 Three examples
 Film actors
 Power grid
 C. elegans
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10. Small-world network (4/7)
 The time to global infection is nearly as
short as for a random graph
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11. Small-world network (5/7)
 Small-world in the brain: micro view
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12. Small-world network (6/7)
 Small-world in the brain: macro view
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13. Small-world network (7/7)
 Small-world in the brain
 Truncated power law
 Economical(close, cost, conservation)
 Global efficiency, short cut
 High degree nodes are less often highly
clustered
 Isomorphism, patterns of connectivity
 Robust, less vulnerable, balance
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14. Scale-free network (1/3)
 The problem of ER and WS model
 The probability with which a new vertex
connects to the existing vertices is not
uniform
 Most real world networks are open. The
number of vertices may increase
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15. Scale-free network (2/3)
 Two mechanisms
 Networks expand continuously by the
addition of new vertices
 New vertices attach preferentially to sites
that are already well connected
 The development of large networks is
governed by robust-organizing
phenomena
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16. Scale-free network (3/3)
 Power law distribution
 Citation of scientific papers
 Rich-get-richer
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17. Reentrant mapping (1/3)
 Directions
 Corticocortical
 Thalamocortical
 Corticothalamic
 Mutual information
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18. Reentrant mapping (2/3)
 Theory of Neuronal Group Selection
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19. Reentrant mapping (3/3)
 Reentrant mapping and consciousness
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20. Links, issues, and opinions (1/4)
 Undirected and Directed graph(I/O)?
 Hubs/weighted graph ?
 Does a vertex which connect to a hub
increase the probability of being
attached?
 The region between small-world and
scale-free?
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2010/3/19 20
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21. Links, issues, and opinions (2/4)
 Three types of projections and
structural, functional, and effective
point of view
 Micro/macro, local/global
 Structural-functional relation
 Reconfiguration, dynamics
 Is the hypothesis of reentry right?
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22. Links, issues, and opinions (3/4)
 What parameters can be mapped from
brain to social networks?
Small-world
Degeneracy?
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23. Links, issues, and opinions (4/4)
 What’s the stimulus of social network?
 What stimulus force the structure of
social networks change?
 What characteristics should a brain
simulator has?
 Degeneracy, evolutionary, self-organize,
etc…
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24. Reference
 [1] Ed Bullmore, Olaf Sporns, “Complex brain networks: graph
theoretical analysis of structural and functional systems”, Nature
Reviews Neuroscience 10, 186-198 (March 2009)
 [2] Duncan J. Watts, Steven H. Strogatz, “Collective dynamics of 'small-
world' networks”, Nature 393, 440-442 (4 June 1998)
 [3] Albert-László Barabási, Réka Albert, “Emergence of Scaling in
Random Networks”, Science 15 October 1999: Vol. 286. no. 5439, pp.
509 – 512
 [4] Gerald M. Edelman, “Wider than the Sky: The Phenomenal Gift of
Consciousness”, Yale University Press (March 10, 2004)
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