Search

Aims: This study used a behavioral approach‐avoidance task including images of alcoholic beverages to test whether low sensitivity to alcohol (LS) is a phenotypical marker of a dispositional propensity to attribute bottom‐up incentive value to naturally conditioned alcohol cues. Design, setting and participants: Experimental study with a measured individual difference variable at a university psychology laboratory in Missouri, MO, USA. Participants were 178 emerging adults (aged 18–20 years) varying in self‐reported sensitivity to alcohol's acute effects. Measurements Participants completed the alcohol approach‐avoidance task while behavior (response time; RT) and the electroencephalogram (EEG) were recorded. Stimulus‐locked event‐related potentials (ERPs) provided indices of integrated (top‐down and bottom‐up) stimulus incentive value (P3 amplitude) and conflict between top‐down task demands and bottom‐up response propensities (N450 amplitude). Findings Linear mixed models showed faster RT for 'alcohol‐approach' relative to 'alcohol‐avoid' trials for lower‐sensitivity (LS) [meanD ± standard errorD (MD ± SED) = 29.51 ± 9.74 ms, t(328) = 3.03, P = 0.003] but not higher‐sensitivity (HS) individuals (MD ± SED = 2.27 ± 9.33 ms, t(328) = 0.243, P = 0.808). There was enhanced N450 amplitude (response conflict) for alcohol‐avoid relative to alcohol‐approach trials for LS participants (MD ± SED = 0.811 ± 0.198 μV, Z = 4.108, P < 0.001) and enhanced N450 amplitude for alcohol‐approach relative to alcohol‐avoid for HS participants (MD ± SED = 0.419 ± 0.188 μV, Z = 2.235, P = 0.025). There was also enhanced P3 amplitude for alcohol‐approach relative to alcohol‐avoid for LS (MD ± SED = 0.825 ± 0.204 μV, Z = 4.045, P < 0.001) but not HS (MD ± SED = 0.013 ± 0.194 μV, Z = 0.068, P = 0.946). Conclusions: Findings from a human laboratory study appear to support the notion that low sensitivity to alcohol indexes a propensity to attribute bottom–up incentive value to naturally conditioned alcohol cues. [ABSTRACT FROM AUTHOR]

Addiction researchers are interested in the ability of neural signals, like the P3 component of the ERP, to index individual differences in liability factors like motivational reactivity to alcohol/drug cues. The reliability of these measures directly impacts their ability to index individual differences, yet little attention has been paid to their psychometric properties. The present study fills this gap by examining within‐session internal consistency reliability (ICR) and between‐session test–retest reliability (TRR) of the P3 amplitude elicited by images of alcoholic beverages (Alcohol Cue P3) and non‐alcoholic drinks (NADrink Cue P3) as well as the difference between them, which isolates alcohol cue‐specific reactivity in the P3 (ACR‐P3). Analyses drew on data from a large sample of alcohol‐experienced emerging adults (session 1 N = 211, 55% female, aged 18–20 yr; session 2 N = 98, 66% female, aged 19–21 yr). Evaluated against domain‐general thresholds, ICR was excellent (M ± SD; r= 0.902 ± 0.030) and TRR was fair (r = 0.706 ± 0.020) for Alcohol Cue P3 and NADrink Cue P3, whereas for ACR‐P3, ICR and TRR were poor (r = 0.370 ± 0.071; r = 0.201 ± 0.042). These findings indicate that individual differences in the P3 elicited by cues for ingested liquid rewards are highly reliable and substantially stable over 8–10 months. Individual differences in alcohol cue‐specific P3 reactivity were less reliable and less stable. The conditions under which alcohol/drug cue‐specific reactivity in neural signals is adequately reliable and stable remain to be discovered. P3/LPP responses to alcohol/drug cues are increasingly used as measures of individual differences in incentive salience attribution propensity, but limited attention has been paid to their psychometric properties. We provide evidence that alcohol and non‐alcohol reward cue‐elicited P3 responses, but not the difference between them, capture highly reliable and stable between‐person variation. More work is needed to obtain psychometrically sound measures of addiction‐specific between‐person variation in the alcohol/drug cue‐elicited P3/LPP. [ABSTRACT FROM AUTHOR]

Mood disorders, depressive episodes, and other negative mood disturbances are highly prevalent forms of mental illness that can lead to suicide, especially in the absence of psychotherapy and/or pharmacotherapy. Current pharmacotherapeutic options for mood disorders are unimpressive in clinical practice, promoting only minor improvement in affective symptoms while resulting in often intolerable cognitive and somatic side effects, leading to poor patient adherence to drug regimens. Currently, commonly-prescribed antidepressants manipulate the same neurotransmitter systems (dopamine, norepinephrine, and serotonin) targeted by earlier generations of these drugs (e.g., monoamine oxidase inhibitors, monoamine and indoleamine reuptake inhibitors, tricyclic antidepressants) only with improved system specificity. However, there exists a clear need to explore alternative neurochemical systems for use in the pharmacotherapy of mood disorders. One such system is the endogenous cannabinoid system, whose role in mood modulation is explored in this review. [ABSTRACT FROM AUTHOR]

We previously reported that, in male, Long Evans rats, instrumental lever pressing that had been reinforced during limited training under a variable interval (VI) schedule by oral self-administration of a 10% sucrose/10% ethanol (10S10E) solution was insensitive to devaluation of 10S10E. In contrast, lever pressing that had been reinforced under a variable ratio (VR) schedule, or by self-administration of 10% sucrose (10S) alone, was sensitive to outcome devaluation. The relative insensitivity to outcome devaluation indicated that seeking of 10S10E by the VI-trained rats had become an instrumental habit. In the present study we employed an alternative operational definition of an instrumental habit and compared the effect of reversing the action-outcome contingency on lever press performance by rats trained under the same experimental conditions. Male Long Evans rats received daily operant training, in which lever presses were reinforced by 10S10E or 10S, under VI or VR schedules. After nine sessions of VI or VR training, rats were tested over four sessions in which the instrumental contingency was changed so that a lever press would prevent reinforcer delivery for 120 s. We found that rats that had been trained to lever press for 10S10E under the VR schedule showed a greater change in lever pressing across testing sessions than those that had received 10S10E reinforcement under the VI schedule. There was no such interaction with reinforcement schedule for rats that had received only 10S reinforcement during training. These findings are consistent with those of our previous study, and provide further evidence that addition of ethanol to sucrose may promote habitual responding in an instrumental task. [ABSTRACT FROM AUTHOR]