Major Brain Networks With Altered Brain Function In Individuals with Addiction Identified

MedicalResearch.com Interview with:
Professor, Rita Z. Goldstein, PhD
Department of Psychiatry (primary)
and Department of Neuroscience, Friedman Brain Institute (secondary)
Chief, Neuropsychoimaging of Addiction and Related Conditions (NARC) Research Program

Anna Zilverstand PhD
Assistant Professor, Psychiatry

Icahn School of Medicine at Mount Sinai
The Leon and Norma Hess Center for Science and Medicine
New York, NY 10029 

MedicalResearch.com: What is the background for this study? What are the main findings?

Response: In comparison to previous reviews that often focused on investigating select brain circuits, such as the reward network, our review is the first to systematically discuss all brain networks implicated in human drug addiction. Based on more than 100 neuroimaging studies published since 2010, we found that six major brain networks showed altered brain function in individuals with addiction. These brain circuits are involved in a person’s ability to select their actions (executive network), in directing someone’s attention (salience network), in adaptive learning of new behaviors (memory network), in the automatization of behaviors (habit network), in self-reflection (self-directed network) and the valuation of different options (reward network).

When individuals with addiction are confronted with pictures of drug taking, all of these networks become very highly engaged; however, when the same individuals are confronted with scenes depicting other people, their brains show a reduced reaction as compared to healthy individuals, indicating less involvement. Similarly, the brain of an addicted individual is less engaged when making decisions (that are not relevant to their drug taking) or when trying to inhibit impulsive actions. We further found that some impairments of brain functions, such as alterations underlying the difficulty to inhibit impulsive actions, seem to precede drug addiction, as we observe similar impairments in adolescents that later go on to abuse drugs. However, particularly the impairments in the executive network (involved in the ability to inhibit impulsive actions), the valuation network (which computes the value of an option) and the salience network (that directs attention towards events) seem to be getting worse with more severe drug use and also predict if someone is likely to relapse or not.

The good news is that we also found that it is possible to (partially) recover and normalize brain function in these networks through treatment. Importantly, the widespread alterations of brain function were independent of what drug an individual was addicted to (marijuana, alcohol, cigarettes, cocaine, methamphetamine, heroin, amongst others).

MedicalResearch.com: What should readers take away from your report?

Response: In summary, we found wide-spread impairments in brain function that were independent of the substance to which an individual was addicted. These alterations affected many important basic psychological processes, such as attention, learning, decision making or the ability to inhibit impulsive actions.

Overall, individuals with drug addiction showed increased responsiveness (of their brain) to drug-related scenes, but decreased engagement when making decisions, trying to inhibit impulsive actions or being confronted with social scenes, which suggests that their brain is “rewired” such that they are tuned to engage in drug taking, while other functions such as decision making, control over impulsive actions or social interaction receive less (brain) resources. Importantly, there is evidence suggesting both that impairments may precede drug use and get worse with excessive use, while a (partial) recovery of brain function seems possible after therapeutic interventions. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: A better understanding of the impairments in brain function in human drug addiction will be critical to paving the way for the development of novel treatments. The observed wide-spread impairments underlying many different psychological processes suggest that the development of novel “targeted” treatments that address specific impairments separately may be necessary. A related, important, question is to which degree the impairments that we found in the addicted population on average, may affect each individual and if individually tailored targeted treatments may be warranted. A third open and very exciting question is to investigate if these impairments in brain function precede drug use.

Disclosures: This work was supported by a postdoctoral fellowship sponsored by the Netherlands Organisation for Scientific Research and by grants from the American National Institute on Drug Abuse.

Citation:

Anna Zilverstand , Anna S. Huang , Nelly Alia-Klein , Rita Z. Goldstein. Neuroimaging Impaired Response Inhibition and Salience Attribution in Human Drug Addiction: A Systematic Review. Neuron, 2018 DOI: 10.1016/j.neuron.2018.03.048

 

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