No abstract

Cue-induced drug craving and disinhibition are two essential components of continued drug use and relapse in substance use disorders. While these phenomena develop and interact across time, the temporal dynamics of their underlying neural activity remain under-investigated. To explore these dynamics, an analysis of time-varying activation was applied to fMRI data from 62 men with methamphetamine use disorder in their first weeks of recovery in an abstinence-based treatment program. Using a mixed block-event, factorial cue-reactivity/Go-NoGo task and a sliding window across the task duration, dynamically-activated regions were identified in three linear mixed effects models (LMEs). Habituation to drug cues across time was observed in the superior temporal gyri, amygdalae, left hippocampus, and right precuneus, while response inhibition was associated with the sensitization of temporally-dynamic activations across many regions of the inhibitory frontoparietal network. Methamphetamine-related response inhibition was associated with temporally-dynamic activity in the parahippocampal gyri and right precuneus (corrected p-value < 0.001), which show a declining cue-reactivity contrast and an increasing response inhibition contrast. Overall, the declining craving-related activations (habituation) and increasing inhibition-associated activations (sensitization) during the task duration suggest the gradual recruitment of response inhibitory processes and a concurrent habituation to drug cues in areas with temporally-dynamic methamphetamine-related response inhibition. Furthermore, temporally dynamic cue-reactivity and response inhibition were correlated with behavioral and clinical measures such as the severity of methamphetamine use and craving, impulsivity and inhibitory task performance. This exploratory study demonstrates the time-variance of the neural activations undergirding cue-reactivity, response inhibition, and response inhibition during exposure to drug cues, and suggests a method to assess this dynamic interplay. Analyses that can capture temporal fluctuations in the neural substrates of drug cue-reactivity and response inhibition may prove useful for biomarker development by revealing the rate and pattern of sensitization and habituation processes, and may inform mixed cue-exposure intervention paradigms which could promote habituation to drug cues and sensitization in inhibitory control regions.

Cue-induced drug craving and disinhibition are two essential components of continued drug use and relapse in substance use disorders. While these two phenomena develop and interact across time, the temporal dynamics of their underlying neural activity and their interaction remain under-investigated. To explore these dynamics, an analysis of time-varying activation was applied to fMRI data from 62 men with methamphetamine use disorder in their first weeks of recovery in abstinence-based treatment program. Using a mixed block-event, factorial cue-reactivity/Go-NoGo task, and a sliding window across the task duration, dynamically-activated regions were identified in linear mixed effects models (LMEs). Habituation to drug cues across time was observed in the superior temporal gyri, amygdalae, left hippocampus, and right precuneus, while response-inhibition was associated with the sensitization of temporally-dynamic activations across many regions of the inhibitory frontoparietal network. Cue-reactivity and response-inhibition dynamically interact in the parahippocampal gyri and right precuneus (corrected p-value < 0.001) regions, which show a declining cue-reactivity contrast and an increasing response-inhibition contrast. Overall, the declining craving-related activations (habituation) and increasing inhibition-associated activations (sensitization) along the task duration suggest the gradual recruitment of response-inhibition process and the concurrent habituation to drug cues in areas with significant dynamic interaction. This exploratory study demonstrates the time-variance of the neural activations undergirding cue-reactivity, response-inhibition, and their interaction, and suggests potentials to assess this dynamic interaction. This preliminary evidence provides justifications for new avenues in biomarker development and interventions using cue exposure paradigms, which could promote habituation to drug cues and sensitization in inhibitory control regions.

Background: Drug-related cue-reactivity, dysfunctional negative emotion processing, and response-disinhibition constitute three core aspects of methamphetamine use disorder (MUD). These phenomena have been studied independently, but the neuroscientific literature on their interaction in addictive disorders remains scant. Methods: fMRI data were collected from 62 individuals with MUD when responding to the geometric Go or No-Go cues superimposed over blank, neutral, negative-emotional and drug-related background images. Neural correlates of drug and negative-emotional cue-reactivity, response-inhibition, and response-inhibition during drug and negative-emotional blocks were estimated, and methamphetamine cue-reactivity was compared between MUDs and 23 healthy controls (HCs). Relationships between clinical and behavioral characteristics and observed activations were subsequently investigated. Results: MUDs had longer reaction times and more errors in drug and negative-emotional blocks compared to neutral and blank ones. MUDs showed higher drug cue-reactivity than HCs across prefrontal regions, fusiform gyrus, and visual cortices (Z>3.1, p-corrected<0.05). Response-inhibition was associated with activations in the precuneus, inferior parietal lobule, and anterior cingulate, temporal and inferior frontal gyri (Z>3.1, p-corrected<0.05). Response-inhibition in drug cue blocks coincided with higher activations in the visual cortex and lower activations in the paracentral lobule and superior and inferior frontal gyri, while inhibition during negative-emotional blocks led to higher superior parietal, fusiform, and lateral occipital activations (Z>3.1, p-corrected<0.05). Conclusion: Higher visual cortical activations and lower parietal and prefrontal activations during drug-related response-inhibition suggest the down-regulation of inhibitory regions and up-regulation of bottom-up drug cue-reactivity. Our results suggest that drug and negative-emotional cue-reactivity influence response-inhibition, and the study of these interactions may aid mechanistic understandings of addiction and biomarker discovery.