1 / 40

Unraveling BOLD Fluctuations: Insights and Applications

Explore the mysteries of BOLD fluctuations in functional imaging: sources, resolution, paradigms, and clinical utility. Discover optimal field strengths and processing strategies for enhanced applications.

dalev
Download Presentation

Unraveling BOLD Fluctuations: Insights and Applications

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Closer Look at BOLD Fluctuations, Decreases, and Increases Peter A. Bandettini bandettini@nih.gov Section on Functional Imaging Methods FIM.NIMH.NIH.GOV & Functional MRI Facility FMRIF.NIMH.NIH.GOV

  2. Jason Diamond Natalia Petridou Rasmus Birn Niko Kriegeskorte Jerzy Bodurka

  3. Many remaining unknowns • Relationship between neuronal activity and BOLD contrast? • Sources of BOLD variability? • Information content / artifact in time series fluctuations? • Source of BOLD timing and dynamics? • Sources of BOLD signal decreases? • Other sources of functional contrast? • Temporal resolution? • Spatial resolution? • Clinical utility? • Best processing and display strategies? • Best paradigm designs strategies? • Optimal field strength? • Applications..??

  4. Motor (black) Primary Sensory (red) Integrative Sensory (violet) Basic Cognition (green) High-Order Cognition (yellow) Emotion (blue) J. Illes, M. P. Kirschen, J. D. E. Gabrielli, Nature Neuroscience, 6 (3)m p.205

  5. 16 channel parallel receiver coil

  6. 8 channel parallel receiver coil GE birdcage GE 8 channel coil Nova 8 channel coil

  7. Average Temporal Signal-to-Noise ratio Comparison Between Coils Anterior Medial 150% 100% 50% 16 Element Array> GE coil Posterior

  8. Sensitivity Encoding (SENSE) Imaging ≈ 5 to 30 ms 3T single-shot SENSE EPI using 16 channels:1.25x1.25x2mm Pruessmann, et al.

  9. Activation-basedmapping: data smoothing(classical approach) Information-basedmapping: local multivariate analysis 0.47 x 0.47 in plane resolution voxel sets volume scanned with MANCOVA searchlight Cheng, et al. (2001) Neuron,32:359-374 Anatomy BOLD Perfusion Spatial Resolution

  10. Fluctuations

  11. Respiration Effects 3ms Image 26ms Power Spectra Respiration map 49ms 0 0.25 0.5 Hz

  12. Cardiac Effects 3ms Image 26ms Power Spectra Cardiac map 49ms 0 0.68 (aliased) 0.5 Hz

  13. Signal / Thermal Noise Signal / Physiologic Noise Signal to Noise Ratio Resolution, Speed, Surface Coils, Field Strength, etc..

  14. Segmentation using EPI Transient

  15. 0.3 Hz FFT Biswal, et al (1995), MRM 34, 537-541 Laufs, et al (1995), PNAS 100 (19), 11053=11058 Kiviniemi, et al (2000), MRM 44, 373-378 Patterson, et al (2002), NeuroImage 17, 1787-1806 Goldman, et al (2002), Neuroreport Interesting Fluctuations

  16. Respiration fluctuations revisited… Correlation with spontaneous changes in end tidal CO2 R. G. Wise, et al, NeuroImage 21 (2004), 1652-1664

  17. Regions showing decreases during cognitive tasks McKiernan, et al (2003), Journ. of Cog. Neurosci. 15 (3), 394-408

  18. strongly reducedvigilance: rest perception + action sleep tasks “default mode” vegetativestate generalanaesthesia (Gusnard and Raichle 2001)

  19. Greicius, et al (2003), PNAS 100 (1), 253-258 Spatial correlation of decreased signal change regions with regions showing resting state corrrelated fluctuations?

  20. Lexical Task ROI Functional Connectivity: Rest Correlation with Respiration Vol./Time Functional Connectivity: Constant Resp. Correlation with Respiration Vol./Time: Constant Resp.

  21. R. M. Birn, (2001) NeuroImage, 14: 817-826. Increases: linearity Logothetis et al. (2001) Nature, 412, 150-157. P. A. Bandettini et al, (2001) Nature Neuroscience, 4: 864-866.

  22. R.M. Birn, P. A. Bandettini. NeuroImage, (in press) Increases: duty cycle

  23. Decreases: linearity R.M. Birn, P. A. Bandettini. NeuroImage, (in press)

  24. We also see increases during stimulus cessation…

  25. Increase: duration on Decrease: duration off Increase: duty cycle

  26. Balloon Model Parameters

  27. “on” Linearity

  28. “off” linearity

  29. Duty Cycle

  30. Neuronal effects to explain duty cycle effects

  31. Temporal Resolution: potential calibration

  32. In general, the latency of BOLD response is correlated with the washout time of Gd-DTPA bolus. • This correlation is not strong enough to correct the large spatial variations in BOLD response latency. • Future improvements include: • More accurate modeling of BOLD and Gd-DTPA bolus signal changes. • Finding ways to separate arterial and venous contributions.

  33. Many remaining unknowns • Relationship between neuronal activity and BOLD contrast? • Sources of BOLD variability? • Information content / artifact in time series fluctuations? • Source of BOLD timing and dynamics? • Sources of BOLD signal decreases? • Other sources of functional contrast? • Temporal resolution? • Spatial resolution? • Clinical utility? • Best processing and display strategies? • Best paradigm designs strategies? • Optimal field strength? • Applications..??

More Related