One of the major goals of modern human neuroscience research is to establish the relationships between brain structures and functions. Although such a goal was considered unrealistic a decade ago, it now seems attainable, thanks to the advent of anatomical and functional three-dimensional (3D) neuroimaging techniques. There remain, however, a number of key questions that will need to be resolved before a complete human brain map can be realized.

First of all, brain structures and functions are characterized by considerable between-subject variability, which motivates the topic of spatial registration and normalization of brain images taken from different individuals. Secondly, the human brain exhibits several levels of structural and functional organization, both in time and space, ranging from synapses to large-scale distributed networks. Integrating these various levels is both a difficult theoretical neuroscience problem and a major technical challenge for neuroimagers. In this chapter, we will thus try to answer the following questions: Why is anatomy a concern for functional imaging of the brain? How can anatomical landmarks be accurately identified and used as tools for researchers in the domain of functional brain imaging? What are the relationships between gross anatomy, microanatomy, and function?

In the first section, we summarize the basic knowledge about the sulcal and gyral cortical anatomy that we think is a prerequisite for anyone who wants to develop registration and normalization tools based on brain anatomical landmarks. In the second section, we investigate the issue of brain anatomical variability. Interestingly, this issue has emerged from population studies in functional imaging where the low signal-to-noise ratio of positron emission tomography (PET) images made it necessary to average functional images of different subjects. In the third section, we focus on the question of structure/function relationships in the human brain, both at the macroscopic and microscopic levels, to underscore the importance of the link between anatomy and function at the individual level. The development of database projects integrating several sources of information such as cytoarchitectony, electrical stimulation, and electrical recordings, as well as information from functional imaging methods, including PET, functional magnetic resonance imaging (fMRI), event-related potentials, magnetoencephalography, and electroencephalo-graphy, renders ever more critical the need for a common neuroanatomical reference frame.

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