Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Connectome

Connectome: A new paradigm for understanding brain function

  • Login to see the comments

Connectome

  1. 1. CONNECTOME: A NEW PARADIGM FOR UNDERSTANDING BRAIN FUNCTION Emilie Lommers Neurologie, Juin 2014
  2. 2. Network as models of complex systems
  3. 3. The Brain - A complex network Brain organization : segregation and integration
  4. 4. Segregation • Specialized neurons and brain areas in performing specific mental operations • Specific response to specific input features or conjunction of features • Anatomical and functional
  5. 5. F. Gall, P. Broca, …
  6. 6. K. Brodmann, …
  7. 7. Is something important missing? C. Golgi, P. Flechsing, K. Wernicke, …
  8. 8. • Segregated and specialized neuronal units do not operate in isolation • Perceptual and cognitive states requires the coordinated activation of neurons within the cerebral cortex - precise dynamical coordination between segregated elements - through intact axonal and synaptic connectivity Functional Integration
  9. 9. CONNECTOME The Brain - A complex network BRAIN FUNCTION SEGREGATION INTEGRATION BRAIN NETWORK
  10. 10. Brain connectivity: multiple modes • Structural connectivity: pattern of structural connections between neurons, neuronal populations, or brain regions. • Functional connectivity: Pattern of statistical dependencies (e.g. correlations) between distinct (often remote) neuronal elements. • Effective connectivity: Network of causal effects, combination of functional connectivity and structural model.
  11. 11. Honey et al., 2007
  12. 12. Brain connectivity: multiple scales • Microscale: Single neurons and their synaptic connections • Mesoscale: Connections within and between microcolumns or other types of local cell assemblies • Macroscale: Anatomically segregated brain regions and their projections
  13. 13. C. Elegans …
  14. 14. Extraction of Brain Networks from empirical data Hagmann et al. 2008
  15. 15. Graph Theory: Basic definitions Segregation Clustering Motifs Integration Distance Path Length Influence Degree Centrality (Hubs)
  16. 16. Backbone of the structural connectivity of human cerebral cortex Hagmann et al. 2008
  17. 17. Network analyses of the human connectome Each functionally specialized cortical region has a unique connectional fingerprint – a unique set of inputs and outputs. Structural modules : nodes that have similar connections with other nodes. Structural modules reflect functional specificities Connector hubs: links between multiple modules Connectors tend to be areas of multimodal and association cortex
  18. 18. In some networks, highly connected/central hub nodes have a tendency to be highly connected to each other (“rich-club” organization).
  19. 19. RC members include: precuneus, superior parietal and frontal cortex, insula, medial temporal regions Large proportion of short communication paths travel trough RC RC damage has disproportionate effects on network integrityvan den Heuvel et al. 2011
  20. 20. Concluding Remarks • Connectome provides a powerful method to quantitatively describe the topological organisation of brain connectivity. • Disrupted functional and structural connectivities have been associated with several neurological and psychiatric disorders (dementia, ALS, MS, schizophrenia,…) • Connectome could improve understanding of brain diseases in term of aetiopathogeny, clinical manifestations, repair and adaptative mechanisms,… TO BE CONTINUED…
  21. 21. Thank you for your attention!

×