Image by euthman via FlickrDunn’s model discusses the interaction between neurological thresholds and behavior. The nervous system varies between excitation and inhibition. Excitation occurs when neurons are more ready to respond. Inhibition occurs when neurons are less likely to respond or the response is blocked. How these two states react determines how a person will respond.
People have a high or low threshold of response to their environment. They may react in either a passive or active manner. These two scales are on a continuum. Everyone is more or less responsive to their environment and react in a more or less active or passive fashion.
Although this article was directed to those with Asperger's, I find it is a good reference.
For more information on dealing with sensory problems.
I also find that this framework helps me get a long better with my MIL (sensory sensitive), husband (sensory avoidance) as I am a low registration type.