Specific impairments within six large-scale brain networks during drug cue exposure, decision-making, inhibitory control, and social-emotional processing are associated with drug addiction behaviors. Drug addiction is a disorder that encompasses not only excessive drug-seeking and taking, but also fundamental changes in cognition and emotional processing. It comprises core clinical symptoms and behavioral manifestations including a chronically relapsing cycle of intoxication, bingeing, withdrawal, and craving that propels uncontrollable drug use despite adverse consequences and a reduction in the pleasure derived from the drug.
While much of the early research on drug addiction focused on understanding the rewarding properties of the drug, recent research has made it increasingly clear that cognitive and emotional impairments support the initiation, escalation, and maintenance of the cycle of addiction. The Impaired Response Inhibition and Salience Attribution (iRISA) model, which uses multiple neuroimaging modalities, proposed that impairments of two broad neuropsychological functions -- response inhibition (a cognitive process that permits individuals to inhibit their impulses) and salience attribution (the property of tagging something as valuable or important) -- and their underlying neural substrates contribute to the cycle of addiction across a broad range of substances of abuse.
Researchers conducted the current review to update the iRISA model with the most recent evidence from the neuroimaging literature by systematically reviewing 105 task-related neuroimaging studies published since 2010. They found consistent impairments in brain function in six large-scale brain networks during performance of different tasks. While the involvement of these specific brain networks was task-specific, they generally observed that in a drug-related context (e.g., during exposure to drug cues) drug addicted individuals had increased engagement of the brain networks underlying decision making, inhibitory control, and social-emotional processing, but a blunted response during non-drug related tasks.
Two additional networks, which were not discussed in prior reviews of the iRISA model, were found to be relevant to brain function in drug addiction: the "self-directed network," which is activated during self-directed/referential cognitive processes, and the "memory network," involved in flexible, multi-cue learning and memory.
In general, a better understanding of the underlying impaired neural mechanisms in human drug addiction is critical to paving the way for the development of more targeted, evidence-based treatment interventions and timely prevention approaches.
Category(s):Addictions, Drug Addiction
Source material from Science Daily
