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Elements of Brain Biology

Elements of Brain Biology. Everything you’ll wish you had NEVER known about fMRI and the BOLD signal. or. fMRI discussion group, 8 June 2011. Introduction to neural development and effective connectivity. How are brain regions defined and connected ?. A typical vertebrate neuron.

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Elements of Brain Biology

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  1. Elements of BrainBiology Everything you’ll wish you had NEVER known about fMRI and the BOLD signal or fMRI discussion group, 8 June 2011

  2. Introduction to neural development and effective connectivity How are brain regions defined and connected ?

  3. A typicalvertebrateneuron R. Bellairs & E.G. Gray, Essays on the Nervous System (1974)

  4. Three phases of neural development B. Albertset al., Molecular Biology of the Cell, 5th ed. (2008)

  5. Migration of immature neurons D. Rapaport & P. Rakic, Genesis of neurons in the retinal ganglion cell layer of the monkey, J. Comp. Neurol. (1992)

  6. Growth of the commissural axon B. Albertset al., Molecular Biology of the Cell, 5th ed. (2008)

  7. Selectivity of axons Y. von Boxberget al., Guidance and topographic stabilization of nasal chick retinal axons, Neuron (1993)

  8. Sharpening of synaptic connections B. Albertset al., Molecular Biology of the Cell, 5th ed. (2008)

  9. Dynamicbrainanatomyleads to changes in brainfunction Introducingsynapticplasticity

  10. Ocular dominance experiment D. Hubel et al., Plasticity of ocular dominance columns in monkey striate cortex., Philos. Trans. R. Soc. London (1977)

  11. Stimulation of an area lead to synaptic modifications U. Nägerlet al., Bidirectional activity-dependent morphological plasticity in hippocampal neurons., Neuron (2004)

  12. Twokinds of synapticplasticity John Byrne, University of Texas online textbook

  13. Neuronsinvolved in synapticplasticity Homosynaptic Heterosynaptic E M- I M+ + - - Pre-synapticneuron Post-synapticneuron +

  14. An overview of current techniques and their relevance to the interpretation of fMRI signal definingconnectivitymaps

  15. Micro-Network Motifs

  16. Principles of excitation / inhibition circuits N. Logothetis, What you can do and what you cannot do with fMRI, Nature (2008)

  17. Investigatingconnectivity (1): DTI Tim Ellmore (unpublished data)

  18. Investigatingconnectivity (2):AnatomicalMapping D. Fellerman & D. van Essen, Distributed hierarchical processing in the primate cerebral cortex, Cortex (1991)

  19. Concurrent TMS / fMRI:functionalconnectivity T. de Graafet al., Complementary Accounts of Causality in the Visuospatial Judgment Network, PLoS One (2009)

  20. “Colours, like features, follow the changes of the mind.”- Pablo Picasso The brainbowrecombinationproject

  21. The Cre-LoxPrecombination system

  22. The Cre-LoxPrecombination system B. Arenkiel & M. Ehlers, Molecular genetics and imaging technologies for circuit-based neuroanatomy, PLoS One (2009)

  23. Detecting fluorescent braincells J. Livet et al., Transgenicstrategies for combinatorialexpression of fluorescent proteins in the nervoussystem, Nature (2007)

  24. Circuit tracingusing fluorescence J. Livet et al., Transgenicstrategies for combinatorialexpression of fluorescent proteins in the nervoussystem, Nature (2007)

  25. Tracing non-neuronal braincells J. Livet et al., Transgenicstrategies for combinatorialexpression of fluorescent proteins in the nervoussystem, Nature (2007)

  26. 10% of braincells are neurons… The importance of glial cells in the bold signal(s)

  27. Most important braincell types

  28. Role of Astrocytes Genetic Science Learning Center - The Other Brain Cells (2011)

  29. How does a neural response trigger a bold response ?

  30. Message transferat the synapticcleft

  31. Astrocytes and Glutamate reuptake

  32. Oxygencost of neural activity • Fusion of Glu vesicleswith plasma membrane. • Recruitment of othervesicles for nextsynaptic release. • Reuptake of Glu by pre-synapticneuron. • Degradation of left-over Glu in synapticcleft. • De novo Glu synthesisfromGln in pre-synapticneuron. • In prolongedactivity, synthesis of new proteinsfromaxonalextremity and extranuclearsynthesis of new mRNAs. • ATP and AMPc stocks needrefilling in post-synapticneurons.

  33. Vasculature and oxygen diffusion N. Logothetis, What you can do and what you cannot do with fMRI, Nature (2008)

  34. Delayedeffect of BOLD response N. Logothetis, Underpinnings of the BOLD fMRI signal, J. Neurosci. (2003)

  35. Decoding the BOLD response pattern Bloodflowincreases, oxygenretrievalis harder Residual ‘debt’ isdealtwith in a few secs / mins, O2 stocks are replenished Activitystarts, oxygenconsumptionincrease Vasodilation of arterioles Vasoconstriction of arterioles

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