Orbitofrontal cortex response underlies attentional bias towards alcohol related sounds in abstinent alcoholics.

ALBA FERRARA, L.; LYLYK, P.

Buenos Aires

Congreso; International Congress of Radiology ICR 2016; 2016

BACKGROUND: In alcohol addiction, alcohol related stimuli gain salience and involuntarily capture the alcoholic patient?s attention in detriment of competing information. This attentional bias has been mostly assessed using visual stimuli. Passive viewing of alcohol cues are processed by a mesocorticolimbic network which principal nodes are the striatum, amygdala, hippocampus, cingulum and prefrontal regions including the medial prefrontal and orbitofrontal cortex (OFC) (Alba-Ferrara, Muller-Oehring et al. 2015). Little is known about the neural systems invoked by alcohol-related sounds and the interplay between attentional control and alcohol related cues salience in alcoholics, that is, the orienting response towards and away from alcohol-related sounds. AIM: To investigate the neural basis of alcohol salience modulation of top-down attentional control in the auditory channel in alcoholics compared with controls.METHODS: 17 sober alcoholics (ALC) and 16 social drinking controls (CTL) underwent fMRI during a dichotic listening task in which an alcohol related sound (i.e. cork popping out) was paired with a non-alcohol related sound (i.e. engine starting). The alcohol sound was located to either the right or left ear. Trials in which two non-alcohol sounds were paired were the baseline. Participants were instructed to attend to either the left or right ear and reported whether the sound on the attended ear was alcohol related or not by pressing a YES or NO button. Two fMRI-runs with 48 dichotic listening trials each were presented with 3000 ms intertrial-interval. Whole-brain imaging data were acquired at a 3T GE scanner.ANALYSIS: Random effects analysis was conducted with SPM8, where one image per contrast was computed for each subject and subjected to t-tests for group comparison. We calculated whole sample BOLD activation patterns from 3 t-contrasts of interest: a) ?Alcohol sounds presented to the attended ear vs. Alcohol sounds presented to the unattended ear?, b) ?Alcohol sounds presented to the unattended ear vs. Alcohol sounds presented to the attended ear?, and c) ?All trial with alcohol sounds vs. baseline trials?. In addition, this last contrast was performed separately for each group.RESULTS: Behaviorally, both groups showed overall good perfromance with all trial categories being discriminated above chance level. Whole sample BOLD t-contrasts for ?alcohol sounds presented to the attended ear vs. alcohol sounds presented to the unattended ear?, activated the mesocorticolimbic system including the right insula and OFC, the caudate extending to the right thalamus, the hippocampus bilaterally and the left amygdala (punc