Extended Nervous System
Extended Nervous System is a term used to describe the extension of perception and sensory feedback outside the physical body. The extended nervous system does not just relate to the extension of the physical self, but the extension of the mental self as well.
"At a fundamental level, physiological computing represents an extension of the human nervous system", writes Steve Fairclough. "This is nothing new. Our history is littered with tools and artifacts, from the plough to the internet, designed to extend the ‘reach’ of human senses capabilities. As our technology becomes more compact, we become increasingly reliant on tools to augment our cognitive capacity.
Those who run host websites on servers are not running machines. Rather, they are maintaining a symbiotic organism of machine and person, stitched together by source code. Those who maintain web systems have extended nervous systems that encompass those servers. When a website goes down, one's physiology is affected. The heart-rate increases, adrenaline flows into the body, and the server administrator gains the required mindset to rush into triage and reinstate the system.
One's extended nervous system also applies to characters in fictional works. In very well-written books, the reader can feel the triumphs and battles of the characters as if they were their own. Social networks are a natural extension of the social and mental self. Each user extends part of their identity into virtual space, and when that extended self is accessed, a feedback loop occurs. Getting a comment on a blog post or piece of writing becomes the psychological equivalent of receiving a comment in real life.
This mental and physical engagement extends to those who engage in technological interaction as well. When one enters a vehicle, their perception and sense of self automatically extends to the edges of the vehicle. The vehicle's edges are an extension of the self, and a the vehicle itself is an extension of the foot 
- Fairclough, Steve. The Extended Nervous System. Physiological Computing: where brain and body drive technology. Published 6th January 2010. Accessed Oct 2011. http://www.physiologicalcomputing.net/?p=291
- Paul Elek, Paul. Comments and Excerpts from Urban Structure. John Wiley & Sons, Inc., New York. 1968. Pg. 127.