Researchers have identified a part of the brain that intensifies desire for rewards like addiction to cocaine. Activating part of the amygdala, an almond-shaped brain region, intensifies motivation to consume cocaine far beyond ordinary drug levels, similar to its ability to intensify motivation for sweet foods like sugar.
Amygdala plays a key role in drug addiction. For addicts, drugs become so attractive as to cause intense motivation focused entirely on obtaining drugs at the expense of other normal life enjoyment. Researchers implanted rats with a catheter that allowed them to earn doses of cocaine, activating brain region creates intense desire to use cocaine.
Researchers implanted rats with a catheter that allowed them to earn doses of cocaine by poking their noses into small holes in the wall. Whenever rats would poke their nose into one particular hole to earn intravenous cocaine, a laser light would also activate the neurons in the central amygdala at the same time
Poking their nose into a different hole earned identical cocaine, but never activated the amygdala. Rats focused only on the port that earned cocaine together with amygdala-activating laser, consumed much more cocaine than rats without amygdala activation, and avidly nibbled around the laser-cocaine hole for more.
The amygdala activation intensified motivation when cocaine was also present. By contrast, when the researchers temporarily inactivated the amygdala using a painless drug infusion, rats completely stopped responding for cocaine.
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