Prefrontal-habenular microstructural impairments in human cocaine and heroin addiction



White matter in the brain that was previously implicated in animal studies has now been suggested to be specifically impaired in the brains of people with addiction to cocaine or heroin, according to a new study. The study was published in Neuron.

The study looked at the connectivity of the tract between the prefrontal cortex (PFC), a brain region critical for regulating higher-order executive functions, and the habenula, a region that plays a critical role in reward and reward-associated learning. The habenula has emerged as a key driver of drug-seeking behaviors in animal models of addiction. Specifically, signaling from the PFC to the habenula is disrupted in rodent cocaine addiction models, implicating this PFC-habenula circuit in withdrawal and cue-induced relapse behaviors. However, until now, the PFC-habenula path has remained poorly understood in the human brain. Furthermore, its involvement in the neuropathological effects of drugs other than cocaine has not been previously explored.

For the first time in the human brain, a team of researchers used diffusion magnetic resonance imaging (MRI) tractography to investigate the microstructural features of the PFC-habenula circuit in people with cocaine or heroin addiction compared to healthy control participants. Diffusion MRI tractography uses noninvasive brain imaging to model fiber bundles in the living human brain.

“In addition to identifying microstructural differences, specifically reduced coherence in the orientation of the white matter fibers in the cocaine-addicted group that comprised both current cocaine users and those with short-term abstinence, we extended results beyond cocaine (a stimulant) to heroin (an opioid), suggesting that abnormalities in this path may be generalized in addiction,” said the first author of the paper. “Importantly, we found that across all addicted individuals, greater impairment was correlated with earlier age of first drug use, which points to a potential role for this circuit in developmental or premorbid risk factors.”

The results advance ongoing research in the field by targeting a previously unexplored circuit in the pathophysiology of addiction in humans, where deficits may predispose an individual to both the development of drug addiction and to relapse and which may be potentially amenable for individually tailored treatment or prevention efforts.

https://www.cell.com/neuron/fulltext/S0896-6273(22)00816-9

http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fmicrostructural_2&filter=22
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