The differences in neural network activity between methamphetamine abusers and healthy subjects performing an emotion‐matching task: functional MRI study

Abstract

Methamphetamine (MA) abusers commonly exhibit socially problematic behaviors, such as diminished empathy, decreased emotional regulation and interpersonal violence, which may be attributable to alterations in emotional experience. However, few studies have used functional MRI to examine directly the emotional experience of threatening or fearful non-face images in MA abusers. In this study, we investigated possible differences in neural correlates of negative emotional experiences between abstinent MA abusers and healthy subjects using complex visual scenes depicting fear or threat derived from the International Affective Picture System. In within-group analyses, healthy subjects and MA abusers activated a similarly distributed cortical network, prominently including the amygdala, fusiform gyrus, parahippocampal gyrus, ventrolateral prefrontal cortex and inferior frontal cortex. In between-group analyses, however, MA abusers showed a reduced activation in the bilateral dorsolateral prefrontal cortex and insula, and increased activation in the fusiform gyrus, hippocampus, parahippocampal gyrus and posterior cingulate cortex, relative to healthy subjects. Hypoactivation of the insula in MA abusers relative to healthy subjects suggests that the ability to have an emotional response to threatening scenes and empathy for another's pain could be compromised in MA abusers. Hyperactivity in the fusiform gyrus, parahippocampal gyrus and posterior cingulate cortex in MA abusers relative to healthy subjects indicates that threatening and fearful images from the International Affective Picture System may remind MA abusers of episodic memory related to similar experiences. Therefore, functional impairment of these neural networks in MA abusers may contribute to altered emotional experience in social interactions, which could lead to increased negative mood and stress in interpersonal communication.

Chronic methamphetamine treatment induces oxytocin receptor up-regulation in the amygdala and hypothalamus via an adenosine A2A receptor-independent mechanism

“…There is considerable evidence demonstrating abnormalities in the amygdala following chronic MAP use (Kim et al , 2011, London et al , 2004 which is likely to be at least partly responsible for the development of anxiety, stress, depression (Dawe et al , 2009, Goeldner et al , 2011, Morley et al , 2001, Thompson et al , 2004) and social cognitive deficits (Dawe et al, 2009, Volkow et al , 2011. Given that OT is known to stimulate oxytocinergic neurons in the amygdala (Carson et al, 2010c) and that the amygdala is partly responsible for the prosocial, antidepressant and anxiolytic properties of OT (Baumgartner et al, 2008, Debiec, 2005, Domes et al , 2007, Febo et al , 2005, Febo et al , 2009, it would be intriguing to speculate that the upregulation of OTRs in this regions, following chronic MAP administration, may be involved in the modulation of the behavioural consequences of chronic MAP use including depression, anxiety and social deficits.…”

Effects of naltrexone are influenced by childhood adversity during negative emotional processing in addiction recovery

“…Similar tasks have been used to demonstrate functional activation in alcohol-and drugdependent groups in response to negative IAPS images. 38,39 A total of 240 images (120 aversive, 120 neutral) were presented in a block design consisting of two runs. Each run contained eight blocks of six images presented for 5 s each, followed by a 400 ms inter-stimulus interval that consisted of a fixation cross.…”

“…We sought to determine the effects of naltrexone at standard dose (50 mg) during negative emotional processing between groups dependent on alcohol alone, dependent on alcohol and drugs (both in abstinence) and healthy control volunteers. On the basis of previous research showing altered activation in limbic and cortical networks during negative emotional processing in substance-dependent individuals, 1,[10][11][12][13][14][15] including the processing of evocative 16 and negative emotional images, 38,39 we hypothesized that the dependent groups would show increased activation in the amygdala, the mPFC and the hippocampus in response to aversive images. In light of preclinical evidence, 29 we further hypothesized that these effects would be modulated by naltrexone depending on the degree of childhood adversity experienced.…”

“…Effects of MOR blockade on different types of substance dependence Previous fMRI studies have shown altered limbic activation in response to naturally evocative, 16 negative emotional 37,38 and substance-related [74][75][76][77][78] stimuli in substance-dependent groups. We observed greater task-related activation in the right amygdala during the processing of aversive relative to neutral images under placebo in individuals recovering from alcohol dependence.…”

“…Heightened reactivity in this region is consistent with previous investigations measuring brain response to negative IAPS images in individuals with alcohol dependence. 38 Similar to our alcohol group, participants from the above studies were characterized by only one drug dependency. The lack of discriminatory response between aversive and neutral images was specific to our alcohol/ drugs group, possibly reflecting an emotional desensitization following prior exposure to adverse events, an attentional disengagement to aversive images (although we consider this unlikely as our task does not tap into attentional resources) or altered MOR availability/density associated with abstinence from repeated drug exposure (for example, cocaine; 79,80 opiates; 81 alcohol 82,83 ) and/or individual differences in environment factors.…”