Summary: Examining the brains of frequent cannabis users, researchers have identified a pattern of connectivity related to craving the substance. The findings add weight to the idea that brain regions do not work in isolation, but via the connectivity of multiple networks that signal to each other depending on state and need. Brain connectivity during cannabis cravings is not static but has fluctuations in connection patterns between the central executive network and nucleus accumbens.
Source: Center for BrainHealth
Researchers at Center for BrainHealth, part of The University of Texas at Dallas, recently examined underlying brain networks in long-term cannabis users to identify patterns of brain connectivity when the users crave or have a desire to consume cannabis. While regional brain activation and static connectivity in response to cravings have been studied before, fluctuations in brain network connectivity had not yet been examined in cannabis users. The findings from this study will help support the development of better treatment strategies for cannabis dependence.
The study was published in the journal of Human Brain Mapping (May 2020) by researchers Francesca Filbey, PhD, professor and director of cognitive neuroscience research of addictive disorders at Center for BrainHealth, Hye Bin Yoo, PhD and Blake Edward Moya.
The findings add to the understanding that regions of the brain do not perform in isolation, but through connectivity of multiple brain networks that signal to each other depending on need and state. It further identifies that brain connectivity during craving is not static, but rather, has fluctuations in connection patterns between reward-related regions such as the central executive network and the nucleus accumbens, areas rich in dopamine. It also highlighted the need to better understand the impact of these dynamic patterns as it relates to cannabis use. Participants were examined with a functional magnetic resonance imaging (fMRI) scanner for these findings.
These findings further extend an earlier study published by Filbey et al in PNAS (August 2009), wherein the Filbey Lab described the first evidence of underlying neural mechanisms during cravings of cannabis users. The findings showed that chronic users not only have increased neural response in reward-related brain regions when there is a desire to consume cannabis, but that the magnitude of the response is associated with the severity of cannabis-related problems.
“Now that we have identified there are differences in large-scale brain network patterns in long-term cannabis users when there is craving, we can use these as biomarkers of cannabis use disorder to aid treatment strategies. Future studies are needed to determine how these brain network patterns might change over the course of treatment and recovery,” said Dr. Filbey.
Funding: This study was helped funded by the National Institute of Drug Abuse, “Genetic and Environmental Modulators of the Brain’s Response to Marijuana Cues” grant.
About this neuroscience research article
Source: Center for BrainHealth Media Contacts: Stephanie Hoefken – Center for BrainHealth Image Source: The image is in the public domain.
Dynamic functional connectivity between nucleus accumbens and the central executive network relates to chronic cannabis use
The neural mechanisms of drug cue‐reactivity regarding the temporal fluctuations of functional connectivity, namely the dynamic connectivity, are sparsely studied. Quantifying the task‐modulated variability in dynamic functional connectivity at cue exposure can aid the understanding. We analyzed changes in dynamic connectivity in 54 adult cannabis users and 90 controls during a cannabis cue exposure task. The variability was measured as standard deviation in the (a) connectivity weights of the default mode, the central executive, and the salience networks and two reward loci (amygdalae and nuclei accumbens); and (b) topological indexes of the whole brain (global efficiency, modularity and network resilience). These were compared for the main effects of task conditions and the group (users vs. controls), and correlated with pre‐ and during‐scan subjective craving. The variability of connectivity weights between the central executive network and nuclei accumbens was increased in users throughout the cue exposure task, and, was positively correlated with during‐scan craving for cannabis. The variability of modularity was not different by groups, but positively correlated with prescan craving. The variability of dynamic connectivity during cannabis cue exposure task between the central executive network and the nuclei accumbens, and, the level of modularity, seem to relate to the neural underpinning of cannabis use and the subjective craving.cted by COVID‐19 presenting with features of microangiopathic damage.