Abstract:

The cue-provoked craving is one of the main reasons for psychological dependence. The current study applied cue reactivity paradigm to find out the activation of whole brain in the drug dependent individual’s brain when they exposed in the related cues. 15 abstinent heroin dependent individuals (AHD) and 12 no-drug use health participants (NDP) involved in the experiment. We conducted 2 (groups: abstinent drug dependent group, no-drug use group) × 2 (related condition: related cue, unrelated cue) × 2 (cue types: static object, action) experiment design. They observed the cue-related stimuli and the counterpart cue stimuli while lying in a 3.0T Siemens MRI scanner. Images for heroin-related stimuli contained heroin injection, preparation, and paraphernalia. Neutral images (control) were composed of daily life objects and behavior. We explored and analysis the neuron activation of cue-induced reactivity between the two groups. Conjunction analysis of action related cue and unrelated cue, to explore the difference activity of mirror neuron system within the two conditions and between AHD and NDP. Multiple t-contrasts between related-cues and unrelated-cues were conducted to find out the cue neuronal reactivity which was accompanied with craving. The result showed that drug-related cues activated more brain regions than the corresponding cues which include the occipital-temporal cortex, superior parietal lobule and inferior parietal lobule, orbit-frontal cortex, anterior cingulate cortex and posterior cingulate, hippocampus, thalamus and midbrain for the AHDs. The comparison between activated brain area under drug and “C-drug” cues showed more activation in right hippocampus, precuneus and the posterior cingulate activation for abstinent group. The hemodynamic response in temporal and parietal lobe correlated was consistent when we performed t-contrasts between “C-action” and “C-drug” condition for both of the two group subjects. Abstinent subjects evoked the bilateral middle temporal gyrus, bilateral inferior parietal lobule, the left superior parietal lobule and the right inferior frontal gyrus when they watched drug taking pictures and usual manual motion. The conjunction analysis showed that conjoined action versus drug and “C-action” versus “C-drug” contrast was executed; hippocampus and midbrain were detected for abstinent group. The health control group only evoked occipital-temporal cortex when compared between under “C-action” and “C-drug” cues. In particular, neither hippocampus nor midbrain had an evident response after the same analysis at the health counterpart group. The result of the study indicated that abstinent drug dependent individuals still have craving for the drugs after a period of abstinent symptoms disappearing. The craving would be induced by the related cues which accompany with the activation of medium temporal gyrus, inferior parietal lobule, and inferior frontal gyrus and so on, which belong to mirror neuron system. The area was susceptible to different drug related cues and they might involve in the mental simulation of drug use activation which participates in quick automation processing to drug related cues. Anterior cingulate cortex, posterior cingulated cortex, hypothalamus, hypothalamus, mesocerebrum along with the limbic system play the important role in the cue-induced craving.

Key words: cue-elicited craving, mirror neuron system, embodied cognitive