Article

Incentive motivation is associated with striatal dopamine asymmetry

Department of Psychology & Brain and Behavior Center, University of Haifa, Mount Carmel 31905, Israel.
Biological Psychology (Impact Factor: 3.47). 02/2008; 77(1):98-101. DOI: 10.1016/j.biopsycho.2007.08.001
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ABSTRACT Dopamine plays an important role in modulating incentive motivation, expressed behaviorally as approach behavior. EEG studies report association between approach behavior and asymmetric pattern of activation in anterior cortical regions (as measured by the inverse of EEG alpha power). Therefore, individual differences in incentive motivation may reflect asymmetries in dopaminergic systems. We examined this hypothesis by studying the relationship between self-reported degree of incentive motivation, and asymmetry of D2 receptor availability in healthy volunteers. Nineteen healthy participants were studied with positron emission tomography (PET) and [11C]raclopride to assess the availability of dopamine D2 receptors in left and right striatum. Incentive motivation was assessed by the Achievement scale of the Multidimensional Personality Questionnaire. The Achievement score was negatively correlated with the Asymmetry Index ([R-L]/[R+L]) of D2 receptor availability (r=-.721, p=.001), suggesting that greater positive incentive motivation is associated with higher receptor availability in the left relative to the right hemisphere.

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    • "A study in healthy subjects revealed that R VST DA preferentially responded to unexpected monetary rewards relative to L VST (Martin-Soelch et al. 2011). Another study in healthy controls showed that incentive motivation correlated with resting D2 receptor availability in the left putamen; an interpretation of these data is that greater endogenous right putamen DA (relative to left putamen) predicts higher drive (Tomer et al. 2008). In Parkinson's disease patients, right hemisphere DA deficits corresponded with reduced novelty seeking, relative to controls (Tomer and Aharon-Peretz 2004), also suggesting lateralized striatal DA function. "
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    ABSTRACT: Although striatal dopamine (DA) is important in alcohol abuse, the nature of DA release during actual alcohol drinking is unclear, since drinking includes self-administration of both conditioned flavor stimuli (CS) of the alcoholic beverage and subsequent intoxication, the unconditioned stimulus (US). Here, we used a novel self-administration analog to distinguish nucleus accumbens (NAcc) DA responses specific to the CS and US. Right-handed male heavy drinkers (n = 26) received three positron emission tomography (PET) scans with the D-2/D-3 radioligand [C-11]raclopride (RAC) and performed a pseudo self-administration task that separately administered a flavor CS of either a habitually consumed beer or the appetitive control GatoradeA (R), concomitant with the US of ethanol intoxication (0.06 g/dL intravenous (IV) administration) or IV saline. Scan conditions were Gatorade flavor + saline (Gat&Sal), Gatorade flavor + ethanol (Gat&Eth), and beer flavor + ethanol (Beer&Eth). Ethanol (US) reduced RAC binding (inferring DA release) in the left (L) NAcc [Gat&Sal > Gat&Eth]. Beer flavor (CS) increased DA in the right (R) NAcc [Gat&Eth > Beer&Eth]. The combination of beer flavor and ethanol (CS + US), [Gat&Sal > Beer&Eth], induced DA release in bilateral NAcc. Self-reported intoxication during scanning correlated with L NAcc DA release. Relative to saline, infusion of ethanol increased alcoholic drink wanting. Our findings suggest lateralized DA function in the NAcc, with L NAcc DA release most reflecting intoxication, R NAcc DA release most reflecting the flavor CS, and the conjoint CS + US producing a bilateral NAcc response.
    Psychopharmacology 08/2014; 232(5). DOI:10.1007/s00213-014-3720-1 · 3.99 Impact Factor
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    • "Nonetheless, several studies suggest that endogenous DA asymmetry can be correlated with affective behaviors as well. For example, human baseline asymmetry in D2 receptor availability in the left relative to the right striatum was associated with greater positive incentive motivation (Tomer et al., 2008; Martin-Soelch et al., 2011). Moreover, human subjects with higher D2 binding in the left hemisphere were sensitive to learning from positive reinforcement whereas those with higher D2 binding in the right hemisphere were sensitive to learning from negative reinforcement (Tomer et al., 2014). "
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    ABSTRACT: The mesostriatal dopaminergic system, which comprises the mesolimbic and the nigrostriatal pathways, plays a major role in neural processing underlying motor and limbic functions. Multiple reports suggest that these processes are influenced by hemispheric differences in striatal dopamine (DA) levels, DA turnover and its receptor activity. Here, we review studies which measured the concentration of DA and its metabolites to examine the relationship between DA imbalance and animal behavior under different conditions. Specifically, we assess evidence in support of endogenous, inter-hemispheric DA imbalance; determine whether the known anatomy provides a suitable substrate for this imbalance; examine the relationship between DA imbalance and animal behavior; and characterize the symmetry of the observed inter-hemispheric laterality in the nigrostriatal and the mesolimbic DA systems. We conclude that many studies provide supporting evidence for the occurrence of experience-dependent endogenous DA imbalance which is controlled by a dedicated regulatory/compensatory mechanism. Additionally, it seems that the link between DA imbalance and animal behavior is better characterized in the nigrostriatal than in the mesolimbic system. Nonetheless, a variety of brain and behavioral manipulations demonstrate that the nigrostriatal system displays symmetrical laterality whereas the mesolimbic system displays asymmetrical laterality which supports hemispheric specialization in rodents. The reciprocity of the relationship between DA imbalance and animal behavior (i.e., the capacity of animal training to alter DA imbalance for prolonged time periods) remains controversial, however, if confirmed, it may provide a valuable non-invasive therapeutic means for treating abnormal DA imbalance.
    Frontiers in Systems Neuroscience 06/2014; 8:110. DOI:10.3389/fnsys.2014.00110
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    • "Using functional magnetic resonance imaging (fMRI) others have found location-specific increases of blood flow in left as compared to right dorsolateral prefrontal cortex during approachrelated goal pursuit, and that this increase was positively correlated to trait approach-motivation (Berkman and Lieberman, 2010). Moreover, an [11C]raclopride positron emission tomography (PET) study found that relative leftward directed asymmetries in striatal dopaminergic activity were associated with higher level of approach motivation (Tomer et al., 2008). These data not only indicate that hemispheric asymmetries are present on the subcortical level, but also suggest reciprocal cortico–striatal–thalamo–cortical interactions. "
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    ABSTRACT: According to the frontal cortical asymmetry model of motivational direction, anger and aggression are associated with approach motivation and a dominant left frontal hemisphere. Functional interhemispheric connectivity has been proposed as a possible mechanism that could explain the frontal cortical asymmetry of anger and aggression. Reciprocal interactions between the cerebral hemispheres are primarily established by the corpus callosum which is the largest white matter bundle of the human brain. Experimental brain research has now provided evidence for callosal involvement in approach-motivation. In line with the frontal cortical asymmetry model of motivational direction, differences in the direction of interhemispheric signal transfer are proposed to contribute to anger and aggression. It is concluded that the human corpus callosum provides a possible neuroanatomical correlate for frontal cortical asymmetries and that interhemispheric signal transfer plays a role in the emergence of approach-related motivation and behaviour.
    Neuroscience & Biobehavioral Reviews 07/2013; 37(10). DOI:10.1016/j.neubiorev.2013.07.013 · 10.28 Impact Factor
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