2014 2nd neuralactivityimaging_pe_tand_cal2
- 1. Neural Activity Imaging Experimental & Clinical Choi Hongyoon
- 3. How Neurons Work C.elegans Whole Brain Activity Ahrens MB, et al. Nat Method 2013. In an entire brain
- 4. http://connectivity.brain- map.org/ Analysis of Wiring Brain Neuronal Activity Coherence Oh SW, et al. Nature 2014.
- 5. Functional Connectivity Mapping Based on Large-scale, Whole Brain Connectivity Patterns of Specific Activity How to analyze these functional activity patterns?
- 6. Choi H, et al. NeuroImage 2014. Lee H, et al. IEEE Trans Med Imaging 2012. Processing Biological Signals Neuronal Activity Measurement
- 8. Clinical Functional Imaging • Scale: Entire Brain FDG PET & Water PET (or PET with other tracers) • Biological Meaning & High-Sensitivity/Relatively good localization • Low temporal resolution: Repetitive Imaging fMRI • High-temporal resolution: Repetitive Measures • Biological Meaning and Resolution EEG/MEG/NIRS(Near Infrared Spectroscopy) • Low Spatial Resolution
- 9. Experimental Functional Measures • Intrinsic/Extrinsic Optical Imaging – Intrinisic: Laser Doppler Flowmetry, fOCT, NIRS, etc – Extrinsic: Voltage-sensitive dye, Calcium indicator High-sensitive & High spatial & temporal resolution Invasive / Cellular Scale (Entire Brain?)
- 10. What is the next step? Mesoscale Structural Analysis Technique Cellular-level Neuromodulation Ultrasensitive & Ultrafast Neuronal Activity Measurement Nature 2013. (News)
- 11. Today Topic Readout Methods breaking the limitations Clinical – PET – Single-session Experimental – Calcium Imaging – Ultrasensitive/High-Resolution
- 12. NeuroImage 2014. Clinical – PET – Single-session
- 13. Image Session >100 times BOLD Signal for single session FDG PET “Minutes-scale” Metabolic Demands“Seconds-Scale” oxygen response
- 14. New Methods for Dynamic Changes of Regional Metabolism
- 15. METHODS • PET/MR (3T Trio + PET insert) • FDG Infusion – 5 mCi & 0.01 mL/s for 90 min – List mode acquisition & 1 min x 90 frames.
- 16. METHODS Principles of dynamics of CMRglu : Kinetic Modeling (derived by classic model) Cp Cf Cm k1 k2 k3 Ct 𝑑𝐶𝑡 𝑑𝑡 = 𝑑𝐶 𝑚 𝑑𝑡 + 𝑑𝐶 𝑓 𝑑𝑡 𝑑𝐶 𝑚 𝑑𝑡 =𝑘3 𝐶𝑓 𝑑𝐶 𝑓 𝑑𝑡 =𝑘1 𝐶 𝑝- (𝑘2 + 𝑘3)𝐶 𝑓 Assumption : Steady state Cf = constant
- 17. Cp Cf Cm k1 k2 k3 Ct 𝑑𝐶𝑡 𝑑𝑡 = 𝑑𝐶 𝑚 𝑑𝑡 + 𝑑𝐶 𝑓 𝑑𝑡 0 Cf = constant CMRglu= k1k3/(k2+k3) * Cp/LC = 1 𝐿𝐶 × 𝑑𝐶 𝑚 𝑑𝑡 CMRglu ~ dCt/dt
- 18. Visual Stimulation Real Data from ROIs Slope is CMRglu GLM and remove baseline linear function
- 19. Plasma Activity of the Brain Slope of the TAC >30min : Almost steady.
- 20. Averaged CMRglu map from slope of brain activity (LC=0.89)
- 21. Simulation Data Inc k3 for 10min Real Data FDGuptakerate Fitting : Dual Exponential
- 22. Activation Map (from Single Subject) GLM Regression Voxelwise T-map
- 23. Activation map from 2nd-level analysis
- 24. Blood Volume Dependent ? CBV increased by CO2, but there was no slope change.
- 25. Brain Activity Mapping New Paradigm for PET – Single-scan derived activation map – Individualized Cognitive Tasks – Increasing Statistical Power
- 26. Experimental – Sensitive/High Resolution Imaging Nature 2013.And recent application papers…
- 27. Calcium & Neuron Intracellular Calcium in Neuron – Presynaptic vesicle release – Action potential in dendrites – Nucleus – Gene regulation Subcellular Resolution & microsecond scale changes Grienberger C and Konnerth A Neuron 2012.
- 28. Calcium Indicators Intracellular calcium domain Microelectrode Gene encoded calcium indicator (GECI) Calcium Sensing by - viral gene delivery - Cre-recombinase system = main-stream Grienberger C and Konnerth A Neuron 2012.
- 29. Gene Delivery to Genetically Encoded Calcium Indicator AAV-CAG-GCaMP6-EGFR http://www.med.upenn.edu/gtp/vectorcore/user_docume nts/DB_Catalog_052014.pdf $250 per vial
- 30. GCaMP6 Paper (Chen TW et al. Nature 2013 ) – Currently, a ‘standard’ method for optical neural activity monitoring GCaMP Protein engineering and
- 31. GCaMP • M13-cpGFP-Calmodulin • Gene variants by mutagenesis
- 32. In vitro neuron testing: GCaMP mutagenesis & Screening Test signal intensity : GCaMP6 the most sensitive type 6s,m,f : according to fluorescence half-life >10 folds higher sensitivity than GCaMP3
- 33. In vivo testing : mouse V1 area / AAV-hsyn1-GCaMP V1 neurons : Orientation Specific (a,b,c)
- 34. V1 neurons : Orientation Selectivity
- 35. V1 neurons : Orientation Selectivity
- 36. GABAergic neurons in V1 Intracellular orientation-specific domain
- 37. NOT only for microscale neurons Portugues R, et al. Neuron 2014. Optokinetic response in C.elegans : Whole Brain Imaging
- 38. NOT only for microscale neurons CCD camera based optical imaging in neonate mouse (GCaMP5-tdTomato / Cre-dependent) Gee JM, et al. Neuron 2014.
- 39. In our department… Optical imaging instrument (e.g. IVIS) – CCD-based, GFP detection – possible. – Spatial & Temporal Resolution – Whole-Brain Imaging? Calcium Indicator – Radiotracer for intracellular calcium detection
- 41. Feasibility An example of simple experiment> Dynamic optical imaging for epileptogenesis AAV-GCaMP6-(Fluorescence) • Upenn Vector Core / BSL-1 • Streotaxic injection to hippocampus/amygdala Stimulation : i.v. pilocarpine Dynamic Imaging in IVIS (after skull removal)
- 42. Take Home Message Neural Activity Imaging – Spatial, Temporal Resolution – Micro to macroscale Infusion FDG PET: Kinetically feasible way to measure metabolic activity in a session – Wide-spread application (Tumor/Glucose sensitivity, etc.) Calcium Indicator Imaging – Promising optical techniques – Simplified Methods : Feasible in our lab.
- 44. • Whole Rodent Brain Imaging (Macroscale) – 주로 Cellular scale에서 많이보나… – CCD를 활용해서 더 큰 scale로 보려는 시도는 있 음. – Neonate mouse brain에서 Cre-system활용한 뒤 CCD로 찍은 movie가 최근에 Neuron에..
- 45. • Next Breakthrough? – Imaging : Whole brain & 3D imaging – Noninvasive calcium indicators • PET tracer? / NIR?
Editor's Notes
- #4: Real time cellular scale brain activity imaging. As you can see in this video, the neuronal activities occur simultaneously across the specific brain regions and dynamically changed. These patterns are not random. They have some regular patterns. We don’t know what the pattern means, but neuroscientists believe the patterns have all information, from behavior, thoguths, cognition and our all of the features. So the answer of the who am I could be the patterns of neuronal activity across the brain.
- #11: Deisseroth 도 Optical Readout개발에 열중.
- #21: 기존 보고와 잘 맞는다..
- #28: Calcium ions generate versatile intracellular signals that determine a large variety of functions in virtually every cell type in biological organisms (Berridge et al., 2000), including the control of heart muscle cell contraction (e.g., Dulhunty, 2006) as well as the regulation of vital aspects of the entire cell cycle, from cell proliferation to cell death (Lu and Means, 1993; Orrenius et al., 2003). In the nervous system, calcium ions preserve and, perhaps, even extend their high degree of versatility because of the complex morphology of neurons. In presynaptic terminals, calcium influx triggers exocytosis of neurotransmitter-containing synaptic vesicles (for review, see Neher and Sakaba, 2008). Postsynaptically, a transient rise of the calcium level in dendritic spines is essential for the induction of activity-dependent synaptic plasticity (Zucker, 1999). In another cellular subcompartment, the nucleus, calcium signals can regulate gene transcription (Lyons and West, 2011). Importantly, intracellular calcium signals regulate processes that operate over a wide time range, from neurotransmitter release at the microsecond scale to gene transcription, which lasts for minutes and hours (Berridge et al., 2003).
- #39: Neuron과 Glia에 발현하도록 함. TdTomato는 marker로서 활용. 자극순서는 Visual, SS, Audiosensory
- #47: Figure3
- #48: Figure 5