Study Finds that the Source of Addiction Craving Stems from the Right Ventral Striatum

A recent study done at the Indiana University School of Medicine and reported by Science Daily found that addiction cravings may start in a pea-sized point located deep in the right half of the brain.

In the study, published in the journal Alcoholism: Clinical and Experimental Research, scientists Brandon G. Oberlin, Ph.D., and David A. Kareken, Ph.D., used PET and fMRI to test the brain’s reaction to alcohol. These two types of advanced brain imagining techniques provide detailed imaging of brain activities.

After providing participants with a taste of a sports drink (Gatorade) versus their favored beer, the participants’ brain scans were examined. They showed that the flavor of beer prompted more activity in the right ventral striatum and both frontal lobes of the participant’s brains. After tasting beer, participants reported a desire to drink more. The right ventral striatum inside the brain is connected to motivated behavior and reward.

David A. Kareken, Ph.D., is the deputy director of the Indiana Alcohol Research Center and the professor of neurology at the IU School of Medicine. He conducted a previous study of 49 men, in which he found a taste of beer – without intoxication – induced the release of dopamine, a neurotransmitter that helps control the brain’s reward and pleasure centers. Dopamine is linked to alcohol and drug abuse. The fMRI (functional magnetic resonance imaging) of this more recent study further demonstrated that alcohol craving specifically corresponds with right ventral stratum and frontal lobe activation.

The ventral striatum corresponds with risk, reward, and decision-making. It reconciles reward cognition, reinforcement, and motivation, with dopamine being its primary neurotransmitter. When the brain thinks gain, dopamine increases in the ventral striatum, and when it thinks loss, dopamine decreases. This dopamine mediation influences behavior based on reward-related stimuli.

Dopamine impacts several areas of addiction. Genetic modifications that influence the brain’s dopamine receptors can indicate whether or not the individual will be attracted to stimulants. When an individual consumes stimulants, the brain’s dopamine levels increase, lasting up to several hours. Chronic dopamine elevation, resulting from repeated use of high-dose stimulants, can cause various structural changes in the brain, triggering an addict’s behavioral abnormalities.

When there is dysfunction in the ventral striatum, various disorders can also result, including depression. The ventral striatum is also well established as a major player in reconciling the reinforcing and rewarding effects of drugs and alcohol.

  1. Oberlin, the assistant research professor of neurology, stated: “We believe this is the first study to use multiple brain imaging modalities to reveal both increased blood oxygen levels and dopamine activity in response to the taste of an alcoholic beverage…The combination of these two techniques in the same subjects strengthens the evidence that these effects may be strongest in the right ventral striatum…Our results indicate that the right ventral striatum may be an especially important area for addiction research.”

Addiction treatment is difficult, because psychological withdrawal causes cravings long after the user stops consuming. Moreover, once the craving seems to disappear, it may reemerge when the user is around drug-related stimuli or recollections of use, such as locations, friends or situations that trigger the addiction. The brain’s association networks are highly interconnected.