Food & Water, Shelter, Sex, Nurturing.

• Natural pleasures in life establish habits which dominate our behavior
• All 5 senses provide input
• Hunger, thirst, sexual activity: appetites
• In humans: interpersonal relationships, religion, exercise, art, music, beauty

Nucleus Accumbens - Ventral Tegmental Area (VTA) - Pre Frontal Cortex. The VTA is connected to both the nucleus accumbens and the prefrontal cortex via this pathway and it sends information to these structures via its neurons. The neurons of the VTA contain the neurotransmitter dopamine which is released in the nucleus accumbens and in the prefrontal cortex. This pathway is activated by a rewarding stimulus. This is not the only pathway activated by rewards, other structures are involved too.

When people first try drugs, it is usually a voluntary decision, but after using the drug for a while, it is no longer voluntary.

Brain regions and neuronal pathways

Certain parts of the brain govern specific functions, such as the sensory, motor and visual cortex, the cerebellum for coordination and the hippocampus for memory. Nerve cells or neurons connect one area to another via pathways to send and integrate information. The distances that neurons extend can be short or long, for example, as in the reward pathway. This pathway is activated when a person receives positive reinforcement for certain behaviors ("reward").

This happens when a person takes an addictive drug. The thalamus receives information about pain coming from the body (through the spinal cord pathways and nuclei), and passes the information up to the cortex.

(Substantia Nigra to Nucleus Accumbens and activating Hippocampus and Striatum to Frontal Cortex).

• reward (motivation), pleasure, euphoria, motor function (fine tuning), compulsion, perseveration, decision making.

(Raphe to Nucleus Accumbens and activating Hippocampus and Striatum and Superior and inferior Frontal Cortex).

• mood, memory processing, sleep, cognition.