Drugs and the Limbic System

The Limbic System
The limbic system is a "collective term denoting a heterogeneous array of brain structures at or near the edge of the medial wall of the cerebral hemisphere, in a particular the hippocampus, amygdala, and fornicate gyrus."3 The limbic system is responsible for creating your feelings and motivation.  Your feelings supply the contexts for your sensory and motor activities and can alter how one perceives the world and behaves in it.  This portion of the brain physically connects the survival oriented brain stem with the cognitively oriented cortex.
Parts of the Limbic System

Drugs and the Limbic System
All drugs that people abuse all change the way the limbic system works.  Drugs disrupt the careful modulation of feelings and motivations that underlie normal behavior.  When these feelings lose touch with reality, the person receives artificial relief, pleasure, contentment, and relaxation take over.

The Brain Reward System
The Brain Reward System is a specific limbic circuit that generates the feelings of pleasure.  This system originates in a group of neurons that are located in the mid brain (called the ventral tegmental area, or VTA).  These neurons then connect to a variety of places within the limbic system, but the important connection is to the nucleus accumbens in the basal ganglia.  The basal ganglia are a large, complex set of structures within the limbic system that function in generating movements, some cognitive functions, emotional and motivational activities. When a drug activates the VTA neurons, these neurons releasedopamine into the nucleus accumbens and the person feels pleasure.

Key Components of the Brain Reward System


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