Melzack (1999 p. 1), a pioneer of the theory, defined the neuromatrix as “a genetically built-in matrix of neurons for the whole body (which) produces characteristic nerve-impulse patterns for the body and the myriad (of) somatosensory qualities we feel”.
In lay terms, the neuromatrix is a theory regarding the way the brain interprets the way we experience sensations throughout our body (Melzack 2001). First it must be recognised that all sensations that we feel are merely a construct of the brain. The sense of light touch is carried as an electrical impulse by neurons from the skin to the brain, where the brain deciphers the information, resulting in the recognition of touch at the particular spot on the body (Young et al 2008). Hence you might say that we feel sensations in our brain, not our body (Loeser & Melzack 1999). It is useful to imagine this concept as a “virtual body” inside the brain (Melzack 1999).

However, pain is much more complex than a simple sensation at the skin being relayed and interpreted by the brain (think chronic pain where there is no longer an injury or phantom limb pain after surgery) (Melzack 2001). The experience of pain is thought to be a result of the countless neural networks (the neuromatrix) within your brain interacting between one another (neurosignature). The neuromatrix is to some extent genetically determined, and influences such as emotional state (e.g. happiness, excitement, fear, anger), past experiences with pain, visual input (e.g. the sight of blood) and anxiety can modify the structure and affect the way the messages are relayed, resulting in a differing neurosignature and hence a different experience of pain for each individual, i.e. your pain experience is unique to you (Melzack 2001).

You might think of it as a business meeting: information comes from people around the table looking at the situation from different aspects, e.g. customer relations, company growth & development, finance and marketing. In this example the neuromatrix could be thought of as the table and the people around it, the neurosignature would be considered the discussion back and forth between each of the participants, and the pain experience would be the outcome of the meeting.