1. fMRI: Biological Basis and Experiment Design Intro History Basic mechanism Neurohemodynamic coupling

4. NMR - MRI - fMRI timeline 1922 Stern-Gerlach Electron spin 1936 Linus Pauling Deoxyhemoglobin electronic structure 1937 Isidor Rabi Nuclear magnetic resonance 1952 Nobel prize Felix Bloch, Edward Purcell NMR in solids 1973 Paul Lauterbur, Peter Mansfield NMR imaging 1993 Seiji Ogawa, et al. BOLD effect 1902 Pieter Zeeman Radiation in a magnetic field

5. ... PNAS 22(4):210-216

6. Harrison, Harel et al., Cerebral Cortex 12:225 (2002)

7. BOLD fMRI: Spatial localization

9. Harrison, Harel et al., Cerebral Cortex 12:225 (2002)

10. Basic BOLD Signal inversely proportional to deoxyhemoglobin concentration CBF = cerebral blood flow –increased CBF increases signal strength CBV = cerebral blood volume –increased venous blood volume decreases signal strength CMRO 2 = cerebral metabolic rate of oxygen –increased CMRO 2 decreases signal strength “... blood oxygenation level-dependent (BOLD) contrast: a change in the signal strength of brain water protons produced by the paramagnetic effects of venous blood deoxyhemoglobin.” –Ogawa et al. 1993

11. And here we start speaking in vague generalities.

12. Neural layers and vasculature Duvernoy, Delon & Vanson, Brain Res. Bull., 1981

13. What is neural activity? Neural activity: - increased oxygen consumption (CMRO 2 ) - increased need for glucose (CMR glc )

14. What does blood flow have to do with neural activity? 5m5m Neural activity: - increased oxygen consumption (CMRO 2 ) - increased need for glucose (CMR glc ) Upstream arteries: - increase flow (CBF) brings oxygen and glucose Downstream veins: - increased blood volume (CBV) - decreased deoxyhemoblogin concentration