ABSTRACT
Physiological investigators have developed a wide range of powerful tools that allow the functional analysis of biological systems. In the nervous system, these methods allow the analysis of the activity patterns of individual nerve cells, and can be used to measure the effects of manipulating those nerve cells on system output. However, a complete understanding of the regulation of a function requires knowledge of the full range of cell groups that are involved in its control, and the ways in which those populations of neurons interact. The analysis of neural connectivity, then, becomes a critical component of understanding how a neural system works.
