Development of tolerance. Over time, the brain adapts in a way that actually makes the sought-after substance or activity less pleasurable. In nature, rewards usually come only with time and effort. Addictive drugs and behaviors provide a shortcut, flooding the brain with dopamine and other neurotransmitters.
There are two types of metamorphism: contact metamorphism and regional metamorphism. Contact metamorphism is a type of metamorphism where rock minerals and texture are changed, mainly by heat, due to contact with magma.This is an easy name to recall if you remember that these rocks change by actually coming in contact with something very hot, like magma.egional metamorphism is a type of metamorphism where rock minerals and texture are changed by heat and pressure over a wide area or region. Contact and regional metamorphism differ in both the area and pressure involved.
Contact Metamorphism is a local type of metamorphism that develops at the contact of hot igneous intrusions and the surrounding rocks into which they intrude. The contact metamorphism is driven entirely by addition of heat into the surrounding rocks. Consequently this type of metamorphism is also referred to as thermal metamorphism. Metamorphism is typically restricted to a thin aureole between 1 - 2 km wide adjacent to the pluton or batholith. Since this environment is not associated with strong deformation, the metamorphic rocks in contact aureoles usually do not exhibit foliation.