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This volume covers the latest developments in optical imaging of the brain which is becoming an increasingly important functional neuroimaging method. Optical intrinsic signals offer unrivaled temporal and spatial resolution of functional measurements of the exposed brain cortex in animals and humans. Near-infrared spectroscopy and imaging ap proaches permit the noninvasive functional assessment of the human brain at bedside. Main advantages of these optical techniques are the biochemical specificity of the meas urements and the potential of measuring correlates of intracellular and intravascular oxy genation simultaneously. Recent data indicate that one may also measure a more direct correlate of neuronal activity associated with changes in light scattering. In this volume, recent technical progress of the optical method is covered as well as the physiological basis of the measurements. In simultaneous studies, near-infrared spec troscopy measurements are directly compared to other functional methods, especially PET and fMRI and examples are given for new applications of the NIRS-method. Based on re sults obtained with optical methods and other functional techniques the latest in our under standing of the coupling of neuronal activity and cerebral blood flow response is reviewed. This is an important basis for a better understanding of all functional neuroi maging methods which rely on neurovascular coupling such as PET, SPET and fMRI. Fi nally the optical method is put into the perspective of presently available functional neuroimaging methods including fMRI, PET, MEG and EEG.
Table des matières
I. Signal Sources in Functional Neuroimaging.- 1. Functional Neuroimaging: Optical Approaches.- 2. Signal Sources in Bold Contrast FMRI.- 3. The MR T1 Based Perfusion Model.- 4. Is There a Different Type of MR-Contrast in the Early Phase of Functional Activation?.- 5. Signal Sources in PET.- II. New Technical Developments in Near Infrared Spectroscopy of the Brain.- 6. Can We Measure Correlates of Neuronal Activity with Non-Invasive Optical Methods?.- 7. Measurement of Cytochrome Oxidase Redox State by Near Infrared Spectroscopy.- 8. Spatial Resolution Enhancement Through Time Gated Measurements.- 9. Towards Near-Infrared Imaging of the Brain.- III. Applications of NIRS for the Functional Assessment of Brain and Comparison to other Functional Neuroimaging Methods.- 10. Cerebral Oxygenation States as Revealed by Near-Infrared Spectrophotometry.- 11. Brain Oxygenation Monitoring during Cardiopulmonary Bypass by Near Infrared Spectroscopy.- 12. A Role for Near Infrared Spectroscopy in Psychiatry?.- 13. Near-Infrared Spectroscopy in Functional Activation Studies: Can NIRS Demonstrate Cortical Activation?.- 14. Correlation between Absolute Deoxyhaemoglobin [dHb] Measured by Near Infrared Spectroscopy (NIRS) and Absolute R2? as Determined by Magnetic Resonance Imaging (MRI).- 15. Towards Brain Mapping Combining Near-Infrared Spectroscopy and High Resolution 3D MRI.- 16. Assessment of Local Brain Activation: A Simultaneous PET and Near-Infrared Spectroscopy Study.- IV. Coupling of Brain Activity and Cerebral Blood Flow and Functional Neuroimaging Methods.- 17. Metabolic Aspects of Neurovascular Coupling.- 18. Metabolic Coupling during Activation: A Cellular View.- 19. Neuronal-Vascular Coupling: A Unifying Hypothesis.- 20. Understanding Functional Neuroimaging Methods Basedon Neurovascular Coupling.- 21. Dynamic NMR Studies of Perfusion and Oxidative Metabolism during Focal Brain Activation.- 22. Changes of Blood Flow and Oxygen Consumption in Visual Cortex of Living Humans.- 23. Uncoupling of Absolute CBF to Neural Activity.- 24. Vascular Regulation at Sub Millimeter Range: Sources of Intrinsic Signals for High Resolution Optical Imaging.- V. Multimodal Imaging of the Human Brain.- 25. Linking Cerebral Blood Oxygenation to Human Brain Function: Current Issues for Human Neuroscience by Magnetic Resonance Neuroimaging.- 26. Intersubject Analysis of FMRI Data Using Spatial Normalization.- 27. What Do We Expect from Non-Invasive Functional Neuroimaging?.
