Arno Villringer - Böcker

• . . . . At last the doctor will be freed from the tedious interpretation of screens and photographs. Instead, he will examine and scan through his patient directly. Wearing optical-shutter spectacles and aiming a pulsed laser torch, he will be able to peer at the beating heart, study the movement of a joint or the flexing of a muscle, press on suspect areas to see how the organs beneath respond, check that pills have been correctly swallowed or that an implant is savely in place, and so on. A patient wearing white cotton or nylon clothes that scatter but hardly absorb light, may not even have to undress . . . . •. David Jones, Nature (1990) 348:290 Optical imaging of the brain is a rapidly growing field of heterogenous techniques that has attracted considerable interest recently due to a number of theoretical advantages in comparison with other brain imaging modalities: it uses non­ ionizing radiation, offers high spatial and temporal resolution, and supplies new types of metabolic and functional information. From a practical standpoint it is important that bedside examinations seem feasible and that the implementations will be considerably less expensive compared with competing techniques. In October 1991, a symposium was held at the Eibsee near Garmisch, Germany to bring together the leading scientists in this new field.

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.

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.