Methods in Molecular Biology-Dynamic Brain Imaging: Multi-Modal Methods and In Vivo Applications
Yale University,New Haven,CT,USA

Textbook: Dynamic Brain Imaging: Multi-Modal Methods and In Vivo Applications
Author(s): Fahmeed Hyder

Description::
chapter 1 presents  a brief introduction to dynamic imaging of brain activity in vivo as measured by various magnetic resonance, electrophysiological, and optical methods.
The next four chapters are on optical imaging. In the third chapter, Lawrence B. Cohen and his colleagues illustrate some state-of-the-art examples of dynamic imaging of olfactory bulb activity with voltage– and calcium-sensitive dyes. They describe the utilities of both single– and two-photon imaging techniques and discuss the types of noise that may confound detection of these optical signals. In the fourth chapter, Serge Charpak and his colleagues discuss the use of two-photon laser scanning microscopy to measure blood flow. They combine these optical recordings with localized intra– and extracellular electrical recordings to examine the coupling between vascular and electrical signals at the level of individual functional units. The fifth chapter by Maiken Nedergaard and her colleagues deals with neurogliovascular coupling. They use novel optical imaging results to demonstrate the involvement of astrocytic calcium signaling and discuss activation-flow coupling in the cerebral cortex. To achieve this, they combined optical recordings from glia with electrical and blood flow measurements in a tour de force of multimodal dynamic brain imaging. The sixth chapter is from Manabu Tanifuji and colleagues and it focuses on the light scattering component of optical intrinsic signals from tissues. Optical intrinsic signal imaging has been widely used for visualizing cortical functional structures. They demonstrate that the optical properties unique to light scattering enable us to visualize spatial patterns of retinal activity noninvasively and resolve functional structures in depth.
The next three chapters focus on different electrical techniques. In the seventh chapter,  deal with measurements of large populations of cortical neurons and their relationship with observed behavior. They describe the power of using novel analytical tools (e.g., principal component analysis, statistical pattern recognition) to quantify relationships among neuronal ensembles during behavior. The eighth chapter is by Andreas A. Ioannides. He introduces magnetoen-cephalography (MEG) as an unsurpassed technique with high temporal resolution for mapping biomagnetic (i.e., electrical) brain activity in a noninvasive manner. He discusses the signal source of MEG and demonstrates numerous examples of using this method to understand dynamic brain function in humans. The ninth chapter by Hal Blumenfeld and his colleague demonstrates imaging of generalized spike-wave seizures in both animals and humans. They demonstrate the power of combining conventional electrical methods (e.g., electroencephalogram and extracellular recordings) with fMRI to provide better understanding of specific brain regions involved in generating spike-wave seizures.
The following three chapters concentrate on fMRI. The tenth chapter is from my group. Where we describe different rodent sensory paradigms that have been studied with fMRI and neurophysiologic recordings. We demonstrate similarities and differences across different sensory modalities and discuss advantages these models may have for studying neuroscientific questions. The eleventh chapter is by Seiji Ogawa and his colleague. Together, they demonstrate how conventional fMRI can be used to elucidate fast and dynamic interactions between different brain regions, both in animals and humans. They propose the use of paired stimulation paradigms to overcome the temporal limitation of fMRI and demonstrate examples where multi-site interactions can be selectively probed. In the twelfth chapter, Bharat B. Biswal and his colleague wrestle with the resting state low frequency fluctuations in fMRI and blood flow signals which are used to reveal correlations across different brain regions.
The last three chapters are on emerging magnetic resonance techniques that have great potential for future neuroscience studies. In the thirteenth chapter, Afonso C. Silva and his colleague describe the magnetic resonance imaging (MRI) measurement of blood flow in the brain using magnetically labeled water. They describe novel manipulations of the conventional MRI used to measure steady-state blood flow in order to probe dynamic changes in perfusion during function. The fourteenth chapter is by Allen W. Song and his colleagues. They describe an MRI method that detects the Lorentz effect induced by neuroelectric activity. They use an array of in vitro models to reveal that this effect can be titrated by synchronization of the MRI pulse sequence with the stimulation paradigm. An example from the human arm is used to demonstrate its potential use in brain imaging in the future. In the last and fifteenth chapter, Wei Chen and his colleagues deal with 31P and 17O magnetic resonance spectroscopy (MRS) methods that probe cerebral energetics in both animals and humans. They demonstrate that the significant gains in MRS detection sensitivity at high magnetic fields leads to improvement in spectral and spatial resolutions, thus leading to novel insights about the dynamics of cerebral energetics.