Predictive but not emotional value of Pavlovian stimuli leads to pavlovian-to-instrumental transfer

Reward-predictive stimuli augment instrumental reward-seeking in humans, an effect denoted Pavlovian-to-instrumental transfer (PIT), but the role of differential reward value of these stimuli and of emotional conditioned responses in PIT remains unknown. Fifty one participants experienced a Pavlovian phase that associated two stimuli with either 10p (CS10) or 50p (CS50). Next, participants underwent instrumental training for two responses reinforced with either 10p or 50p. Finally, the transfer phase continued as had instrumental training, now in the presence of the Pavlovian stimuli. Participants were dichotomised as aware/unaware according to their expectancy awareness of the CS → outcome associations. Only aware participants demonstrated PIT (increased choice and number of responses on the 10p and 50p response key in the presence of CS10 and CS50 respectively), yet both aware and unaware groups rated the 50p stimulus as more pleasant than the 10p stimulus. These findings suggest that expectancy of reward is necessary for PIT; however, emotional conditioned responses appear not sufficient to influence PIT. Future research should attempt to manipulate emotional conditioned responses in a PIT context, to test the sufficiency of reward expectancy in PIT

Single-response appetitive Pavlovian to instrumental transfer is suppressed by aversive counter-conditioning

Environmental stimuli, when paired with reward, can influence behaviour in maladaptive ways, for example, by encouraging overeating or addiction. Such behaviour can be sensitive to reward value manipulations, under circumscribed conditions, but whether reward-seeking is also sensitive to stimulus value manipulations remains unclear. Thus, the current experiment investigated whether reducing the hedonic value of a reward-paired stimulus would reduce reward-seeking behaviour. In total, 36 participants successfully completed a single-response Pavlovian-instrumental transfer (PIT) task with a counter-conditioning procedure. The Pavlovian phase associated three conditioned stimuli (CSs) with money at 100%, 50%, or 0% contingency. Counter-conditioning then followed for the experimental group, who saw the 100% CS paired with unpleasant pictures, while the control group saw only neutral images. Instrumental training required participants to learn a button-pressing response to win money. The transfer phase contrasted instrumental responding during baseline and CS presentation. Both experimental and control groups liked the 100% CS more than the other CSs after Pavlovian training, but counter-conditioning reduced this 100% CS liking. In transfer, the experimental group showed an abolition of appetitive PIT, while the control group showed maintenance of appetitive PIT. However, this group difference was only evident in response vigour, not response initiation. In summary, CS hedonic value influences cue-potentiated instrumental responding. More specifically, hedonic value of a reward-paired cue influences the vigour of instrumental responses, but not the decision to initiate a response. These data may have relevance to smoking cessation policies, where the introduction of health warnings may be viewed as a real-world example of counter conditioning

Binge drinking is associated with attenuated frontal and parietal activation during successful response inhibition in fearful context

Binge drinking is associated with increased impulsivity and altered emotional processing. The current study investigated, in a group of university students who differed in their level of binge drinking, whether the ability to inhibit a pre-potent response and to delay gratification is disrupted in the presence of emotional context. We further tested whether functional connectivity within intrinsic resting-state networks was associated with alcohol use. Higher incidence of binge drinking was associated with enhanced activation of the lateral occipital cortex, angular gyrus, the left frontal pole during successful response inhibition irrespective of emotional context. This observation suggests a compensatory mechanism. However, higher binge drinking attenuated frontal and parietal activation during successful response inhibition within a fearful context, indicating the selective emotional facilitation of inhibitory control. Similarly, higher binge drinking was associated with attenuated frontopolar activation when choosing a delayed reward over an immediate reward within the fearful, relative to the neutral, context. Resting-state functional data analysis revealed that binge drinking decreased coupling between right supramarginal gyrus and Ventral Attention Network, indicating alcohol-associated disruption of functional connectivity within brain substrates directing attention. Together, our results suggest that binge drinking makes response inhibition more effortful, yet emotional (more arousing) contexts may mitigate this; disrupted functional connectivity between regions underlying adaptive attentional control, is a likely mechanism underlying these response inhibition effects associated with binge drinking

The impact of yohimbine-induced arousal on facets of behavioural impulsivity

Rationale State-dependent changes in physiological arousal may influence impulsive behaviours. Objectives To examine the relationship between arousal and impulsivity, we assessed the effects of yohimbine (an α2-adrenergic receptor antagonist, which increases physiological arousal via noradrenaline release) on performance on established laboratory-based impulsivity measures in healthy volunteers. Methods Forty-three participants received a single dose of either yohimbine hydrochloride or placebo before completing a battery of impulsivity measures. Blood pressure and heart rate were monitored throughout the study. Results Participants in the yohimbine group showed higher blood pressure and better response inhibition in the Stop Signal Task, relative to the placebo group. Additionally, individual changes in blood pressure were associated with performance on Delay Discounting and Information Sampling tasks: raised blood pressure following drug ingestion was associated with more far-sighted decisions in the Delay Discounting Task (lower temporal impulsivity) yet reduced information gathering in the Information Sampling Task (increased reflection impulsivity). Conclusions These results support the notion that impulsive behaviour is dependent upon state physiological arousal; however, distinct facets of impulsivity are differentially affected by physiological changes

Goal-driven attentional capture by appetitive and aversive smoking-related cues in nicotine dependent smokers

BACKGROUND: Conventionally, involuntary attentional capture by tobacco cues in smokers are seen as an implicit bias, operating independently of current search goals. Prominent attention research, however, has suggested that search goals can induce an involuntary attentional capture. In the current investigation, we tested whether appetitive and aversive smoking images affected attention through such a mechanism and whether there were group differences based on nicotine dependence. METHODS: We instructed non-smokers (NS), occasional smokers (OS; low dependence), and nicotine-dependent smokers (NDS; moderate-high dependence), to hold search goals for either an aversive or appetitive smoking category, or a category of non-smoking images. These images were presented in a stream of briefly appearing filler images, while task-irrelevant distractors were presented outside the stream. Distractors could be aversive or appetitive smoking images or a category of non-smoking images. Therefore, in some conditions, the distractors matched the current category being searched for, while in others it was incongruent. RESULTS: Task-irrelevant smoking distractors reduced target detection, compared to the non-smoking distractors, only when they were congruent with the specific category being searched for. There was no effect of either aversive or appetitive smoking distractors on performance when participants were searching for the non-smoking targets. Distractor interference did not differ between smokers and non-smokers. CONCLUSIONS: The results support a goal-driven mechanism underpinning involuntary attentional capture by smoking cues. These findings can be used to inform models of addiction and attention, and the display of health warnings. KEYWORDS

Prehabilitation in alcohol dependence as a treatment model for sustainable outcomes. A narrative review of literature on the risks associated with detoxification, from animal models to human translational research

In this review paper we discuss how the overarching concept of pre-habilitation is applicable to alcohol dependence. Central to pre-habilitation are the concepts of expected harm, risks and proactive planning to eliminate the harm or cope with the risks. We review the evidence from animal models, psychological experimental studies, as well as pharmacological studies, on the potential risks and harms associated with medically assisted alcohol detoxification and the current treatment paradigm for alcohol dependence. Animal models provide an approximation mostly of the physical aspect of alcohol withdrawal and detoxification process and make predictions about the development of the phenomena in humans. Despite their limitations, these models provide good evidence that withdrawal from chronic ethanol use induces cognitive impairment, which is worsened by repeated bouts of withdrawal and that these impairments are dependent on the duration of alcohol withdrawal. Initial clinical observations with alcohol dependent patients confirmed increased incidence of seizures. In recent years, accumulating evidence suggest that patients who have had repeated episodes of withdrawal also show changes in their affect, increased craving as well as significant deterioration of cognitive abilities, when compared to patients with fewer withdrawals. Alcohol dependence is associated with tolerance and withdrawal, with neuroadaptations in GABA-A and glutamatergic N-methyl-D-aspartate (NMDA) receptors playing key roles. It is suggested that dysregulation of the NMDA receptor system underpins alcohol related memory impairments. Finally we discuss the Structured Preparation for Alcohol Detoxification (SPADe) as an example of how pre-habilitation has been applied in clinical practice. We discuss the importance of partial control over drinking as an interim step towards abstinence and early introduction of lifestyle changes for both the patient and the immediate environment prior detoxification and while the patient is still drinking