Major depression is conditionally linked to a polymorphism of the human serotonin transporter gene (SLC6A4). During the presentation of aversive, but not pleasant, pictures, healthy carriers of the SLC6A4 short (s) allele showed stronger activation of the amygdala on functional magnetic resonance imaging. s carriers also showed greater coupling between the amygdala and the ventromedial prefrontal cortex, which may contribute to the abnormally high activity in the amygdala and medial prefrontal cortex seen in major depression.

This pilot study showed that cue-induced activation of the anterior cingulate, medial prefrontal cortex and striatum may play a role in the attribution of incentive salience to alcohol-associated stimuli, thus increasing the motivational value and attentional processing of alcohol cues. Functional brain imaging may help to identify a group of alcoholics with an otherwise undetected high risk of relapse.

No abstract

Catechol-O-methyltransferase (COMT) degrades the catecholamine neurotransmitters dopamine, epinephrine, and norepinephrine. A functional polymorphism in the COMT gene (val 158met) accounts for a fourfold variation in enzyme activity. The low-activity met 158 allele has been associated with improved working memory but with higher risk for anxiety-related behaviors. Using functional magnetic resonance imaging, we assessed the effects of COMT genotype on brain activation by standardized affective visual stimuli (unpleasant, pleasant, and neutral) in 35 healthy subjects. The analysis of genotype effects was restricted to brain areas with robust activation by the task. To determine gene-dose effects, the number of met 158 alleles (0, 1, or 2) was correlated with the blood oxygen level-dependent (BOLD) response elicited by pleasant or unpleasant stimuli compared with neutral stimuli. COMT genotype had no significant impact on brain activation by pleasant stimuli but was related to the neural response to unpleasant stimuli: reactivity to unpleasant stimuli was significantly positively correlated with the number of met 158 alleles in the limbic system (left hippocampus, right amygdala, right thalamus), connected prefrontal areas (bilateral ventrolateral prefrontal cortex, right dorsolateral prefrontal cortex), and the visuospatial attention system (bilateral fusiform gyrus, left inferior parietal lobule). Genotype explained up to 38% of interindividual variance in BOLD response elicited by unpleasant stimuli. We conclude that (1) genetic variations can account for a substantial part of interindividual variance in task-related brain activation and that (2) increased limbic and prefrontal activation elicited by unpleasant stimuli in subjects with more met 158 alleles might contribute to the observed lower emotional resilience against negative mood states.

Computer games have become an ever-increasing part of many adolescents' day-to-day lives. Coupled with this phenomenon, reports of excessive gaming (computer game playing) denominated as "computer/video game addiction" have been discussed in the popular press as well as in recent scientific research. The aim of the present study was the investigation of the addictive potential of gaming as well as the relationship between excessive gaming and aggressive attitudes and behavior. A sample comprising of 7069 gamers answered two questionnaires online. Data revealed that 11.9% of participants (840 gamers) fulfilled diagnostic criteria of addiction concerning their gaming behavior, while there is only weak evidence for the assumption that aggressive behavior is interrelated with excessive gaming in general. Results of this study contribute to the assumption that also playing games without monetary reward meets criteria of addiction. Hence, an addictive potential of gaming should be taken into consideration regarding prevention and intervention.

SummaryWith no further intervention, relapse rates in detoxified alcoholics are high and usually exceed 80% of all detoxified patients. It has been suggested that stress and exposure to priming doses of alcohol and to alcohol-associated stimuli (cues) contribute to the relapse risk after detoxification. This article focuses on neuronal correlates of cue responses in detoxified alcoholics. Current brain imaging studies indicate that dysfunction of dopaminergic, glutamatergic, and opioidergic neurotransmission in the brain reward system (ventral striatum including the nucleus accumbens) can be associated with alcohol craving and functional brain activation in neuronal systems that process attentional relevant stimuli, reward expectancy and experience. Increased functional brain activation elicited by such alcohol-associated cues predicted an increased relapse risk, while high brain activity elicited by affectively positive stimuli may represent a protective factor and was correlated with a decreased prospective relapse risk. These findings are discussed with respect to psychotherapeutic and pharmacological treatment options.

Alcohol-associated cues may act as conditioned stimuli that activate the brain reward system and motivate alcohol intake in alcoholics. Alcohol-associated visual stimuli were presented during functional magnetic resonance imaging. An activation of the ventral putamen was observed in alcoholics but not in control subjects. Patients with a strong activation of the ventral putamen relapsed during the next three months. This observation supports the hypothesis that alcohol use affects areas involved in brain reward circuits and that their stimulus-induced activation may be associated with an increased risk for relapse.

The objective of this study was to develop new standardized alcohol-associated cues and assess their effects on brain activation with functional magnetic resonance imaging (fMRI). Pictures of alcoholic and neutral beverages and affectively neutral pictures were presented to 44 abstinent alcoholics and 37 age-matched healthy control subjects. We assessed the skin conductance response, and the elicited arousal and valence. Alcoholics and control subjects did not differ in arousal, valence or skin conductance response evoked by alcohol-associated and affectively neutral stimuli, while nonalcoholic beverages were rated as more unpleasant and arousing by alcoholics compared with control subjects. In the fMRI pilot study, alcohol and abstract pictures were presented to six abstinent alcoholics and induced a significant activation of brain areas associated with visual emotional processes such as the fusiform gyrus, parts of the brain reward system (basal ganglia and orbitofrontal gyrus) and further brain regions in the frontal and parietal cortices associated with the attention network. These observations suggest that standardized pictures of alcoholic beverages can be used to assess brain circuits involved in the processing and evaluation of alcohol cues.