Addiction and the Brain

Structures of the brain


  • Frontal lobe
behavior, abstract thought processes, problem solving, creative thought, some emotion, intellect, reflection, judgement, initiative, inhibition, coordination of movements, generalized and mass movements, some eye movements, sense of smell, muscle movements, skilled movements, some motor skills, physical reaction, libido
  • Occipital Lobe

Vision, Reading

  • Parietal Lobe

Auditory memories, some hearing, visual memories, some vision pathways, other memory, music, fear, some language, some speech. some behavior and emotions, sense of identity

  • Right Hemisphere

Controls the left side of the body, temporal and spatial relationships, analyzing nonverbal information, communicating emotion

  • Left Hemisphere

Controls the right side of the body, produces and understands language

  • Corpus Callosum

Communication between the left and right side of the brain

The Cerebellum

Balance, posture, cardiac, respiratory, & vasomotor centers
  • The brain stem

motor & sensory pathway to body and face

vital centers- cardiac, respiratory, & vasometer

  • Hypothalamus

Moods and motivation

sexual maturation

temperature regulation

hormonal body processes

  • Optic Chiasm

vision and the optic nerve

  • Pituitary Gland

hormonal body processes

physical maturation

growth (height and form)

sexual maturation

sexual functioning

  • Spinal Cord

conduit and source of sensation and movement

  • Ventricals and Cerebral Adueduct

Contains the cerebrospinal fluid that bathes the brain and spinal cord

Reward Pathway

  • Reward pathway- involves several parts of the brain, the ventral tegmental area, the nucleus accumbens, and the prefrontal cortex. Most important is the DOPAMINE SYSTEM.
  • Ventral tegmental area- collection of neurons situated at the center of the midbrain, functions as a sort of receptor core, receiving messages from different parts of the brain
  • Nucleus accumbens- when activated, dopamine levels increase
  • Prefrontal cortex- in charge of thinking and thought analysis, responsible for regulating behavior

How do drugs affect the brain.

"Drugs are chemicals that affect the brain by tapping into it's communication system and interfering with the way neurons normally send, receive, and process information,. Some drugs, such as marijuana and heroin, can activate neurons because their chemical structure mimics that of a natural neurotransmitter." - National Institute on Drug Abuse Most drugs tend to target the brain's reward system by filling it with dopamine. Dopamine ( a neurotransmitter) is present in parts of the brain that regulates movement, emotion, motivation, and feelings of pleasure. Activated on normal levels, the system rewards our natural behaviors but when you overstimulate it with drugs it produces euphoric effects, which strongly reinforces the behavior of drug use, (teaching the user to repeat it.)


Dopamine's impact on the reward circuit of the brain of someone who uses drugs can become abnormally low, and that person's ability to experience any pleasure is reduced. This is why people who abuse drugs eventually feel lifeless and depressed. They no longer find things pleasurable that used to be. Now that person must keep taking more and more drugs just to bring back that dopamine level back to normal. This only makes the problem worse and usually the person will have to take even larger amounts of the drug to get that usual dopamine high, this effect is known as tolerance.