Characteristics of function-specific pathways in the sympathetic nervous system.

The autonomic nervous system enables all of our body systems to operate in an external environment that is both physically and emotionally challenging. Despite voluntary and involuntary interventions, the composition of the internal environment is maintained. Autonomic dysfunction, particularly in aging people, reveals the importance of this efferent neural control for the wellbeing of our bodies and minds. Although the sympathetic component of this system has been widely thought to be concerned only with the body's response to stress, we discuss here how a range of neuroscientific techniques has started to reveal the specialized properties of functional pathways in the sympathetic system at molecular, cellular and integrative levels. The diversity observed is not compatible with a simple neuroendocrine role of this system.