Impulsive Personality Predicts Dopamine-Dependent Changes in Frontostriatal Activity during Component Processes of Working Memory

University of Cambridge, Cambridge, England, United Kingdom
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.34). 06/2007; 27(20):5506-14. DOI: 10.1523/JNEUROSCI.0601-07.2007
Source: PubMed


Dopaminergic drugs affect a variety of cognitive processes, but the direction and extent of effects vary across individuals and tasks. Paradoxical effects are observed, by which the same drug causes cognitive enhancing as well as adverse effects. Here, we demonstrate that individual differences in impulsive personality account for the contrasting effects of dopaminergic drugs on working memory and associated frontostriatal activity. We observed that the dopamine D2 receptor agonist bromocriptine improved the flexible updating (switching) of relevant information in working memory in high-impulsive subjects, but not in low-impulsive subjects. These behavioral effects in high-impulsive subjects accompanied dissociable effects on frontostriatal activity. Bromocriptine modulated the striatum during switching but not during distraction from relevant information in working memory. Conversely, the lateral frontal cortex was modulated by bromocriptine during distraction but not during switching. The present results provide a key link between dopamine D2 receptor function, impulsivity, and frontostriatal activity during component processes of working memory.

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Available from: Emily G Jacobs, Aug 13, 2014
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    • "This pharmacological fMRI study addresses the functional architecture of the human striatum and dopaminergic influences on striatal information processing (Cools et al. 2007; Dalley et al. 2007; Belin et al. 2008). We manipulated the connectivity between motivational, cognitive, and motor portions of the striatum with dopaminergic drugs, and we exploited interindividual differences in mesostriatal dopamine systems to explain trait-dependent effects of the dopaminergic manipulations. "
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    ABSTRACT: Interactions between motivational, cognitive, and motor regions of the striatum are crucial for implementing behavioral control. Work with experimental animals indicates that such interactions are sensitive to modulation by dopamine. Using systematic pharmacological manipulation of dopamine D2-receptors and resting-state functional imaging, we defined the functional architecture of the human striatum and quantified the effects of dopaminergic drugs on intrinsic effective connectivity between striatal subregions. We found that dopamine modulates interactions between motivational and cognitive regions, as well cognitive and motor regions of the striatum. Stimulation and blockade of the dopamine D2-receptor had opposite (increasing and decreasing) effects on the efficacy of those interactions. Furthermore, trait impulsivity was specifically associated with dopaminergic modulation of ventral-to-dorsal striatal connectivity. Individuals with high trait impulsivity exhibited greater drug-induced increases (after stimulation) and decreases (after blockade) of ventral-to-dorsal striatal connectivity than those with low trait impulsivity. These observations establish a key link between dopamine, intrinsic effective connectivity between striatal subregions, and trait impulsivity.
    Full-text · Article · Oct 2015 · Cerebral Cortex
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    • "; Braver and Cohen , 2000 ; Cohen et al . , 2002 ; Dreisbach , 2006 ) . More precisely , it has been suggested that positive affect modulates cognitive control and cognitive flexibility by increasing the neurotransmitter dopamine in specific brain regions , namely in the striatum and the prefrontal cortex ( Ashby et al . , 1999 ) . More recently , Cools et al . ( 2001 , 2007 ) and Cools ( 2008 ) provided a refined version of this account by showing that the neural structure in which dopamine levels are sensitive to positive affect are indeed involved in the modulation of cognitive control . They reported evidence that increased dopamine in the striatum increased cognitive flexibility , while increased dopam"
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    ABSTRACT: The temporal relationship between our conscious intentions to act and the action itself has been widely investigated. Previous research consistently shows that the motor intention enters awareness a few hundred milliseconds before movement onset. As research in other domains has shown that most behavior is affected by the emotional state people are in, it is remarkable that the role of emotional states on intention awareness has never been investigated. Here we tested the hypothesis that positive and negative affects have opposite effects on the temporal relationship between the conscious intention to act and the action itself. A mood induction procedure that combined guided imagery and music listening was employed to induce positive, negative, or neutral affective states. After each mood induction session, participants were asked to execute voluntary self-paced movements and to report when they formed the intention to act. Exposure to pleasant material, as compared to exposure to unpleasant material, enhanced positive affect and dampened negative affect. Importantly, in the positive affect condition participants reported their intention to act earlier in time with respect to action onset, as compared to when they were in the negative or in the neutral affect conditions. Conversely the reported time of the intention to act when participants experienced negative affect did not differ significantly from the neutral condition. These findings suggest that the temporal relationship between the conscious intention to act and the action itself is malleable to changes in affective states and may indicate that positive affect enhances intentional awareness.
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    • "For this reason, and following many other studies, we here focused on drug effects on the relative measure (i.e., face vs. scene, referred to as distracter cost) which controls for such non-specific effects. A second caveat of the present study is that we failed to replicate previous research showing that dopaminergic drug effects were most pronounced in high-impulsive subjects (Cools et al. 2007). We were not able to replicate this finding here, probably because our sample sizes for the low-and highimpulsive groups were too small. "
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    ABSTRACT: Dopamine has long been implicated in the online maintenance of information across short delays. Specifically, dopamine has been proposed to modulate the strength of working memory representations in the face of intervening distracters. This hypothesis has not been tested in humans. We fill this gap using pharmacological neuroimaging. Healthy young subjects were scanned after intake of the dopamine receptor agonist bromocriptine or placebo (in a within-subject, counterbalanced, and double-blind design). During scanning, subjects performed a delayed match-to-sample task with face stimuli. A face or scene distracter was presented during the delay period (between the cue and the probe). Bromocriptine altered distracter-resistance, such that it impaired performance after face relative to scene distraction. Individual differences in the drug effect on distracter-resistance correlated negatively with drug effects on delay period signal in the prefrontal cortex, as well as on functional connectivity between the prefrontal cortex and the fusiform face area. These results provide evidence for the hypothesis that dopaminergic modulation of the prefrontal cortex alters resistance of working memory representations to distraction. Moreover, we show that the effects of dopamine on the distracter-resistance of these representations are accompanied by modulation of the functional strength of connections between the prefrontal cortex and stimulus-specific posterior cortex.
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