Optical Imaging of Neocortical Dynamics

When mammals such as mice, cats, monkeys, or humans act in the world, they continually make behaviorally relevant decisions based on perceived sensory information and memorized experiences and they constantly adapt to outside challenges through learning. These cognitive capabilities largely arise from neural processing in the outermost thin sheet of the forebrain called the neocortex. Although the mammalian neocortex has been studied extensively, the astounding complexity of both its structure and dynamics has precluded a comprehensive understanding of its function so far. Higher cortical function emerges from the interplay of myriads of diverse neocortical cells, organized across multiple hierarchical levels from local neuronal networks (“microcircuits”) to communicating brain regions (“macrocircuits”). It remains elusive how these neural circuits operate—assisted by glial networks and fuelled by the vascular system—to generate intelligent behavior and ensure adequate learning. Advances in experimental methodology are essential to further unravel cortical function and in this book we highlight the rapid recent progress in optical methods for measuring and controlling neocortical dynamics, complementing classic electrophysiological approaches. In this chapter we provide a brief overview of the functional organization of the neocortex, its tissue constituents, and current concepts of neocortical dynamics. In preparation of subsequent chapters, we summarize the manifold ways photons can be used to study neocortical function, utilizing specially designed molecular tools and various imaging technologies. We conclude with a brief future outlook. Putting neocortex literally “into the spotlight” may help uncover its intriguing mysteries.