Chapter 1
Introduction
Ll Motivation
The mechanisms behind cognition and human consciousness are possibly two of the most
important mysteries confronting modern science. In investigating these questions through
study of the brain and nervous system, research in neuroscience is not only an endeavor
to advance medical care and understanding of neurological diseases, but an effort to learn
what makes us human. Although we have made a lot of progress in 60 years of modern
neuroscience research in understanding specific brain systems, we still seem far away from
a comprehensive picture of how the brain works.
The brain is a complex tissue with tens of billions of neurons, whose convoluted and
heterogeneous interconnections lead to an unknown number of interlinked and interde-
pendent circuits. In order to understand it all it would seem that we would have to have a
tool to analyze the behavior of all of these circuits simultaneously. Some tools like fMRI can
observe the activity of nearly the entire brain, and tell which areas of the brain are active
at a given time by their oxygen demand. However, fMRI can only give a very broad view
of which areas of the brain are active due to its limited spatial, and particularly temporal
resolution. It cannot necessarily tell what those areas are doing. An fMRI image of the brain