Chronic effects of cannabis use on the human reward system: An fMRI study
ABSTRACT Cannabis is one of the most used drugs of abuse. It affects the brain reward system in animals, and has proven rewarding and addictive potential in humans. We used functional MRI to measure brain activity during reward anticipation in a monetary reward task. Long-term cannabis users were compared to healthy controls. An additional control group consisting of nicotine users was included. Cannabis users showed attenuated brain activity during reward anticipation in the nucleus accumbens compared to non-smoking controls, but not compared to smoking controls. Cannabis users showed decreased reward anticipation activity in the caudate nucleus, compared to both non-smoking and smoking controls. These data suggest that nicotine may be responsible for attenuated reward anticipation activity in the accumbens, but that differences in the caudate are associated with the use of cannabis. Our findings imply that chronic cannabis use as well as nicotine, may cause an altered brain response to rewarding stimuli.
- SourceAvailable from: Pascal Pas
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- "For optimal reward cues, functional MRI data showed significant brain activation for high (vs. low) reward cues (see also Van Hell et al. 2010), especially in the ventral striatum and ventral pallidum, which are output channels of the striatal dopamine system (Heimer and Van Hoesen 2006). However, although there was a significant increase in the effort people invested in the task for high versus low reward cues, no significant differences in brain activation were found for suboptimal reward cues. "
ABSTRACT: Reward cues have been found to increase the investment of effort in tasks even when cues are presented suboptimally (i.e. very briefly), making them hard to con-sciously detect. Such effort responses to suboptimal reward cues are assumed to rely mainly on the mesolimbic dopa-mine system, including the ventral striatum. To provide further support for this assumption, we performed two studies investigating whether these effort responses vary with individual differences in markers of striatal dopami-nergic functioning. Study 1 investigated the relation between physical effort responses and resting state eye-blink rate. Study 2 examined cognitive effort responses in relation to individually averaged error-related negativity. In both stud-ies effort responses correlated with the markers only for suboptimal, but not for optimal reward cues. These findings provide further support for the idea that effort responses to suboptimal reward cues are mainly linked to the mesolimbic dopamine system, while responses to optimal reward cues also depend on higher-level cortical functions.Motivation and Emotion 09/2014; 38(6). DOI:10.1007/s11031-014-9434-1 · 1.55 Impact Factor
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- "The main effects of task were in line with those reported in earlier work. Activation during Reward Anticipation (contrast Anticipation Reward versus Anticipation Neutral ) was found in the ventral striatum, putamen, thalamus, anterior cingulate cortex, mid-cingulate cortex, insula and several frontal, temporal and parietal areas (Bjork et al., 2010, 2004; Carter et al., 2009; Dillon et al., 2008; Ernst et al., 2004; Figee et al., 2011; Galvan et al., 2005; Hermans et al., 2010; Hommer et al., 2003; Knutson et al., 2001a,b; Knutson et al., 2003; Ossewaarde et al., 2011; Van Hell et al., 2010). Reward Outcome activity (contrast Feedback Reward versus Feedback Correct Neutral) was mainly found in the orbitofrontal cortex, caudate, posterior cingulate gyrus and bilateral parahippocampal gyri. "
ABSTRACT: Typical adolescent behaviour such as increased risk-taking and novelty-seeking is probably related to developmental changes in the brain reward system. This functional MRI study investigated how brain activation related to two components of reward processing (Reward Anticipation and Reward Outcome) changes with age in a sample of 39 children, adolescents and young adults aged 10-25. Our data revealed age-related changes in brain activity during both components of reward processing. Activation related to Reward Anticipation increased with age, while activation related to Reward Outcome decreased in various regions of the reward network. This shift from outcome to anticipation was confirmed by subsequent analyses showing positive correlations between age and the difference in activation between Reward Anticipation and Reward Outcome. The shift was predominantly present in striatal regions and was accompanied by a significant effect of age on behaviour, with older participants showing more response speeding on potentially rewarding trials than younger participants. This study provides evidence for functional changes in the reward system which may underlie typical adolescent behaviour.09/2013; 6C:113-124. DOI:10.1016/j.dcn.2013.08.004
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- "Moreover, responses in this region to food-related stimuli have been shown to be increased when participants are in a state of hunger (LaBar et al., 2001). Increased ventral striatal BOLD responses to drug-related cues have been associated with craving and drug withdrawal (Kilts et al., 2001, 2004; Rolls and McCabe, 2007; Wrase et al., 2007), although opposite effects have also been observed for non-drug related reward cues (Wrase et al., 2007; van Hell et al., 2010). Based on behavioral findings described above, we expected to find a more generally increased reward sensitivity in women in the premenstrual phase, and therefore predicted that ventral striatal activation during anticipation of monetary rewards would be enhanced in the premenstrual phase. "
ABSTRACT: The premenstrual phase of the menstrual cycle is associated with marked changes in normal and abnormal motivated behaviors. Animal studies suggest that such effects may result from actions of gonadal hormones on the mesolimbic dopamine (DA) system. We therefore investigated premenstrual changes in reward-related neural activity in terminal regions of the DA system in humans. Twenty-eight healthy young women underwent functional magnetic resonance imaging on 2 days during the menstrual cycle, once during the late follicular phase and once during the premenstrual phase, in counterbalanced order. Using a modified version of the monetary incentive delay task, we assessed responsiveness of the ventral striatum to reward anticipation. Our results show enhanced ventral striatal responses during the premenstrual as compared to the follicular phase. Moreover, this effect was most pronounced in women reporting more premenstrual symptoms. These findings provide support for the notion that changes in functioning of mesolimbic incentive processing circuits may underlie premenstrual changes in motivated behaviors. Notably, increases in reward-cue responsiveness have previously been associated with DA withdrawal states. Our findings therefore suggest that the sharp decline of gonadal hormone levels in the premenstrual phase may trigger a similar withdrawal-like state.Social Cognitive and Affective Neuroscience 10/2011; 6(5):612-20. DOI:10.1093/scan/nsq071 · 5.88 Impact Factor