The Pleasure Principle: The Brain Mechanism Involved in Drug Addictive Behavior

  The habitual use of addictive substances can be directly mediated by our brains reward systems. These reward systems in our brain are activated upon our retrieval of food, water, and sexual activity. Engaging in activities that directly excite the reward systems in our brain causes dopamine to be released and elicit a pleasing sensation. Drugs of abuse, specifically act on the brains reward center via the mesolimbic pathway. An area within the mesolimbic pathway, the ventral tegmental area (VTA) is specifically targeted by dopamine and contributes to the reinforcement of drugs of abuse.  In his speech, Dr. Stephen Steidel discussed his research and described how this mechanism is directly shown in mice.

            An electrode was inserted into the midbrain of mice, the excitement of dopamine levels was assessed as the mice were able to self-administer light to their VTA area. Mice were placed in a chamber with two holes, one hole was a control and the other turned on a light directly exciting dopamine neurons ( Steidel). As dopamine neurons excite the VTA, action potentials in the midbrain drastically increase. This mechanism supports how drugs of abuse target dopamine neurons, and reinforces addict’s behaviors by directly mediating on their reward system giving users a pleasing sensation that keeps them coming back for more.

            In an news article CenterCite describes how drugs of abuse, and specifically stimulant drugs keep individuals returning despite their harmful effects on their body “Although different addictions have different effects in the nucleus accumbens, they all activate the reward system. This in turn motivates us to repeat those behaviors, even though they may be harmful”(Horvath).

                                                                        Work Cited

Steidal, Stephan. “Role of laterodorsal tegmental nucleus cholinergic and glutamatergic inputs to ventral tegmental area in reinforcement, drug reward, and sensitization.” Neuroscience Seminar. Loyola University Chicago, Chicago.1Sep.2015.Speech.

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