Conditioned cues for smoking elicit preparatory responses in healthy smokers

Effectiveness of residential versus outpatient therapy for smoking cessation: The START randomized clinical trial

BACKGROUND AND AIMS

Tobacco smoking represents a major cause for preventable death and morbidity. Results from non-randomized studies suggest that smoking cessation therapy in a residential setting might be a new viable way to facilitate smoking abstinence. We aimed to test the effects of residential multicomponent group therapy for smoking cessation compared with outpatient group therapy.

DESIGN

Prospective parallel-group open-label randomized superiority trial, with assessments at baseline, 6 and 12 months.

SETTING

Recruitment throughout Germany via media advertisements.

PARTICIPANTS

Adult smokers (≥10 cigarettes/day) randomly assigned to residential (n = 157) or outpatient (n = 158) therapy. 51.8% female; mean age 53.2 years; mean years of smoking 34.4.

INTERVENTION AND COMPARATOR

Residential 9-day smoking cessation group therapy comprising six daily therapy sessions and supportive interventions for cessation and daily structure embedded in the routines of a somatic rehabilitation center, compared with weekly outpatient smoking cessation group therapy (3-7 weeks) provided in routine care courses close to the participants' places of residence, both including at least 9 h of behavioral therapy.

MEASUREMENTS

Co-primary outcomes were self-reported continuous 6- and 12-month abstinence (hierarchically ordered). Primary analyses were conducted in the therapy-uptake population including participants who started therapy with sensitivity analyses in the intention-to-treat population of all randomized participants.

FINDINGS

Intervention uptake rates were 87.3% (n = 137) in the residential and 60.1% (n = 95) in the outpatient group. In the therapy-uptake population, abstinence rates were 46.7% in the residential versus 26.3% in the outpatient group at 6 months (odds ratio [OR] = 2.46, 95% confidence interval [CI] = 1.39-4.33, P = 0.0019) and 39.4% versus 24.2% at 12 months (OR = 2.04, 95% CI = 1.14-3.64, P = 0.017). Biochemically validated abstinence rates at 12 months were 33.1% in the residential versus 17.4% in the outpatient group (OR = 2.35, 95% CI = 1.22-4.51, P = 0.011). In the intention-to-treat population, self-reported and biochemically validated abstinence rates at 12 months were 34.4% in the residential versus 14.6% in the outpatient group (OR = 3.08, 95% CI = 1.77-5.34, P < 0.0001) and 28.6% versus 10.3% (OR = 3.48, 95% CI = 1.85-6.52, P = 0.0001), respectively.

CONCLUSIONS

Residential therapy exclusively for smoking cessation is feasible and effective and could be a beneficial new treatment for smokers.

Psychometric properties of the German Penn Alcohol Craving Scale

Craving for alcohol is an important diagnostic criterion in alcohol use disorder (AUD) and an established predictor of future relapse. The 5-item Penn Alcohol Craving Scale (PACS) is one of the most widely used questionnaires to quantify craving and has been translated into different languages. It is assumed that the PACS constitutes one factor, although theoretical considerations suggest an additional second factor. We conducted stability and factor analyses (principal component and confirmatory factor analyses) of the German PACS (PACS-G) in samples of patients with AUD from the following three German study sites: Erlangen, N = 188 (mean age: 47.1 years, 43.5% female); Mannheim, N = 440 (45.5 years, 28.6% female); Hannover, N = 107 (48.1 years, 48.6% female). In our samples, the 2-factor solution of the PACS-G version is more stable than the internationally assumed 1-factor solution. The resulting two PACS-G subscores 'difficulty to resist' (items 4 and 5) and 'thoughts about alcohol' (items 1, 2, and 3) have an internal consistency (Cronbach's alpha) of 0.80 ≤ α ≤ 0.90, m = 0.86 and 0.86 ≤ α ≤ 0.91, m = 0.89 with an overlap of R2 = 62%. We found good convergent validity assessed via the Craving Automatized Scale-Alcohol and the Obsessive-Compulsive Drinking Scale, but also correlations with depression and anxiety assessed via the Beck's Depression and Anxiety Inventories. This study is the first to provide evidence for a 2-factor solution ('difficulty to resist' and 'thoughts about alcohol') underlying the PACS-G version.

Can you learn to starve yourself? Inducing food avoidance in the laboratory

The restriction of energy intake is a central and persistent symptom of anorexia nervosa. Recent models of the disorder suggest that food restrictions are learned avoidance behaviours, which are acquired and maintained by classical and operant conditioning. The present study aims to test this learning model of food restriction. It investigates whether introducing negative consequences for the intake of tasty high-calorie food and introducing positive consequences for its avoidance can create food avoidance, increase fear of food, and decrease eating desires in healthy individuals. 104 women were randomly assigned to an experimental or control condition and completed an appetitive conditioning and avoidance learning task. While the experimental condition received money after avoiding the tasty high-calorie food item and heard an aversive sound after not avoiding food intake, the control condition never received these consequences. In the extinction phase, reward and punishment discontinued for both conditions. We measured avoidance frequency, mouse movements, fear, eating desires and stimulus liking. Participants in the experimental condition avoided the food more often than controls and showed increased fear, reduced eating desires and less liking for cues associated with food intake. These results support the notion that food avoidance behaviours, reduced eating desires and fear of food can be learned via classical and operant conditioning. Conditioning paradigms might be a useful tool to study the development and maintenance of food restriction in anorexia nervosa.

VR for Studying the Neuroscience of Emotional Responses

Emotions are frequently considered as the driving force of behavior, and psychopathology is often characterized by aberrant emotional responding. Emotional states are reflected on a cognitive-verbal, physiological-humoral, and motor-behavioral level but to date, human research lacks an experimental protocol for a comprehensive and ecologically valid characterization of such emotional states. Virtual reality (VR) might help to overcome this situation by allowing researchers to study mental processes and behavior in highly controlled but reality-like laboratory settings. In this chapter, we first elucidate the role of presence and immersion as requirements for eliciting emotional states in a virtual environment and discuss different VR methods for emotion induction. We then consider the organization of emotional states on a valence continuum (i.e., from negative to positive) and on this basis discuss the use of VR to study threat processing and avoidance as well as reward processing and approach behavior. Although the potential of VR has not been fully realized in laboratory and clinical settings yet, this technological tool can open up new avenues to better understand the neurobiological mechanisms of emotional responding in healthy and pathological conditions.

The incentive amplifying effects of nicotine: Roles in alcohol seeking and consumption

Nicotine has a unique profile among drugs of abuse. To the noninitiated user, nicotine has powerful aversive effects and its relatively weak euphorigenic effects undergo rapid tolerance. Despite this, nicotine is commonly abused despite negative heath consequences, and nicotine users have enormous difficulty quitting. Further, nicotine is one of the most commonly co-abused substances, in that it is often taken in combination with other drugs. One explanation of this polydrug use is that nicotine has multiple appetitive and consummatory conditioning effects. For example, nicotine is a reinforcement enhancer in that it can potently increase the incentive value of other stimuli, including those surrounding drugs of abuse such as alcohol. In addition, nicotine also has a unique profile of neurobiological effects that alter regulation of alcohol intake and interoception. This review discusses the psychological and biological mechanisms surrounding nicotine's appetitive conditioning and consummatory effects, particularly its interactions with alcohol.

Stationäre Behandlung exklusiv zur Raucherentwöhnung – Konzept einer intensivierten verhaltenstherapeutischen Gruppentherapie

Zielsetzung Angesichts hoher Morbidität und Mortalität durch Tabakabhängigkeit besteht ein dringender Bedarf an effektiven Angeboten zur Raucherentwöhnung. Die leitliniengemäß durchgeführten ambulanten Therapien sind in ihrer langfristigen Wirksamkeit jedoch limitiert. Im Folgenden wird ein erstmalig in Deutschland entwickeltes wissenschaftliches stationäres Therapiekonzept ausschließlich zur stationären Raucherentwöhnung beschrieben und die Evidenz für die langfristige Effektivität dieser intensivierten Therapieform zur Raucherentwöhnung diskutiert.

Methodik Es handelt es sich um ein multimodales neuntägiges verhaltenstherapeutisches Therapiekonzept für den stationären Einsatz. Die Entwöhnung wird als Gruppentherapie leitliniengemäß von einem mobil einsetzbaren Team geschulter Raucherentwöhner:innen durchgeführt, ergänzt durch Angebote zur Förderung der Gruppenkohäsion, Tagesstrukturierung, zum Bewegungstraining, Ernährungsmanagement, Ressourcenaufbau, Expositionstraining rückfallkritischer Situationen und zur achtsamkeitsbasierten Stressbewältigung.

Schlussfolgerungen Eine stationäre Raucherentwöhnungstherapie ist als vielversprechende Ergänzung bzw. Alternative zur ambulanten Entwöhnung umsetzbar. Die intrinsische Abstinenzmotivation soll in einem geschützten Rahmen bei professioneller Betreuung und Unterstützung in der Gruppe gestärkt werden mit Fokus auf den Transfer der Kompetenzen in den Alltag. Erste Studienergebnisse weisen auf eine hohe langfristige Entwöhnungsquote hin. Eine wissenschaftliche Überprüfung der (Kosten-)Effektivität anhand randomisiert-kontrollierter Studien steht noch aus.

Virtual reality: a powerful technology to provide novel insight into treatment mechanisms of addiction

Due to its high ecological validity, virtual reality (VR) technology has emerged as a powerful tool for mental health research. Despite the wide use of VR simulations in research on mental illnesses, the study of addictive processes through the use of VR environments is still at its dawn. In a systematic literature search, we identified 38 reports of research projects using highly immersive head-mounted displays, goggles, or CAVE technologies to provide insight into treatment mechanisms of addictive behaviors. So far, VR research has mainly addressed the roles of craving, psychophysiology, affective states, cognition, and brain activity in addiction. The computer-generated VR environments offer very realistic, dynamic, interactive, and complex real-life simulations requesting active participation. They create a high sense of immersion in users by combining stereoscopic three-dimensional visual, auditory, olfactory, and tactile perceptions, tracking systems responding to user movements, and social interactions. VR is an emerging tool to study how proximal multi-sensorial cues, contextual environmental cues, as well as their interaction (complex cues) modulate addictive behaviors. VR allows for experimental designs under highly standardized, strictly controlled, predictable, and repeatable conditions. Moreover, VR simulations can be personalized. They are currently refined for psychotherapeutic interventions. Embodiment, eye-tracking, and neurobiological factors represent novel future directions. The progress of VR applications has bred auspicious ways to advance the understanding of treatment mechanisms underlying addictions, which researchers have only recently begun to exploit. VR methods promise to yield significant achievements to the addiction field. These are necessary to develop more efficacious and efficient preventive and therapeutic strategies.

Nicotine Enhances Goal-Tracking in Ethanol and Food Pavlovian Conditioned Approach Paradigms

Rationale

Nicotine promotes alcohol intake through pharmacological and behavioral interactions. As an example of the latter, nicotine can facilitate approach toward food- and alcohol-associated stimuli ("sign-tracking") in lever-Pavlovian conditioned approach (PavCA) paradigms. However, we recently reported that nicotine can also enhance approach toward locations of reward delivery ("goal-tracking") triggered by ethanol-predictive stimuli when the location of ethanol delivery is non-static (i.e., a retractable sipper bottle).

Objective

To determine whether the non-static nature of the reward location could have biased the development of goal-tracking in our previous study (Loney et al., 2019); we assessed the effect of nicotine in a lever-PavCA paradigm wherein the location of ethanol delivery was static (i.e., a stationary liquid receptacle). Then, to determine whether nicotine's enhancement of goal-tracking is unique to ethanol-predictive stimuli, we assessed the effect of systemic nicotine on approach triggered by food-predictive stimuli in a lever-PavCA paradigm.

Methods

Long-Evans rats were used in two PavCA experiments wherein a lever predicted the receipt of ethanol (15% vol/vol; experiment 1) or food (experiment 2) into a stationary receptacle. Prior to testing, rats were administered nicotine (0.4 mg/kg subcutaneously) or saline systemically.

Results

In both experiments, nicotine increased measures of goal-tracking, but not sign-tracking.

Conclusion

Nicotine can facilitate approach to reward locations without facilitating approach to reward-predictive stimuli. As such, conceptualization of the mechanisms by which nicotine affects behavior must be expanded to explain an enhancement of goal-tracking by nicotine.

Smoke signals: A study of the neurophysiological reaction of smokers and non-smokers to smoking cues inserted into antismoking public service announcements

Tobacco addiction is one of the biggest health emergencies in the world, Antismoking Public Service Announcements (PSAs) represent the main public tool against smoking; however, smoking-related cues (SCs) often included in PSAs can trigger ambiguous cerebral reactions that could impact the persuasiveness and efficacy of the antismoking message. This study aimed to investigate the electroencephalographic (EEG) response in adult smokers and non-smokers during the exposure to SCs presented in antismoking PSAs video, in order to identify eventual neurophysiological features of SCs' 'boomerang effect' elicited in smokers. EEG frontal Alpha asymmetry and frontal Theta were analyzed in 92 adults (30 no smokers, 31 low smokers, 31 high smokers) from EEG recorded during the vision of 3 antismoking PSAs, statistical analysis was conducted using ANOVA. Main results showed a significant interaction between smoking cue condition (Pre and Post) and smoking habit (in particular for female heavy smokers) for the frontal Alpha asymmetry. Since the relative higher right frontal Alpha activity is associated with approach towards a stimulus, it is suggested that the relative left frontal Alpha increase in response to SCs might reflect an appetitive approach in response to it. In the light of the Incentive Sensitization Theory, this pattern can be interpreted as a neurophysiological signal in response to SCs that could undermine the message's effectiveness contributing to the maintenance of the addiction.

Affective startle modulation and psychopathology: Implications for appetitive and defensive brain systems

Startle reflex potentiation versus startle attenuation to unpleasant versus pleasant stimuli likely reflect priming of the defensive versus appetitive motivational systems, respectively. This review summarizes and systemizes the literature on affective startle modulation related to psychopathologies with the aim to reveal underlying mechanisms across psychopathologies. We found evidence for psychopathologies characterized by increased startle potentiation to unpleasant stimuli (anxiety disorders), decreased startle potentiation to unpleasant stimuli (psychopathy), decreased startle attenuation to pleasant stimuli (ADHD), as well as a general hyporeactivity to affective stimuli (depression). Increased versus decreased startle responses to disorder-specific stimuli characterize specific phobia and drug dependence. No psychopathology is characterized by increased startle attenuation to standard pleasant stimuli or a general hyperreactivity to affective stimuli. This review indicates that the defensive and the appetitive systems operate independently mostly in accordance with the motivational priming hypothesis and that affective startle modulation is a highly valuable paradigm to unraveling dysfunctions of the defensive and appetitive systems in psychopathologies as requested by the Research Domain Criteria initiative.

Where There is Smoke There is Fear-Impaired Contextual Inhibition of Conditioned Fear in Smokers

The odds-ratio of smoking is elevated in populations with neuropsychiatric diseases, in particular in the highly prevalent diagnoses of post-traumatic stress and anxiety disorders. Yet, the association between smoking and a key dimensional phenotype of these disorders-maladaptive deficits in fear learning and fear inhibition-is unclear. We therefore investigated acquisition and memory of fear and fear inhibition in healthy smoking and non-smoking participants (N=349, 22% smokers). We employed a well validated paradigm of context-dependent fear and safety learning (day 1) including a memory retrieval on day 2. During fear learning, a geometrical shape was associated with an aversive electrical stimulation (classical fear conditioning, in danger context) and fear responses were extinguished within another context (extinction learning, in safe context). On day 2, the conditioned stimuli were presented again in both contexts, without any aversive stimulation. Autonomic physiological measurements of skin conductance responses as well as subjective evaluations of fear and expectancy of the aversive stimulation were acquired. We found that impairment of fear inhibition (extinction) in the safe context during learning (day 1) was associated with the amount of pack-years in smokers. During retrieval of fear memories (day 2), smokers showed an impairment of contextual (safety context-related) fear inhibition as compared with non-smokers. These effects were found in physiological as well as subjective measures of fear. We provide initial evidence that smokers as compared with non-smokers show an impairment of fear inhibition. We propose that smokers have a deficit in integrating contextual signs of safety, which is a hallmark of post-traumatic stress and anxiety disorders.

Effect of Selective Inhibition of Reactivated Nicotine-Associated Memories With Propranolol on Nicotine Craving

IMPORTANCE

A relapse into nicotine addiction during abstinence often occurs after the reactivation of nicotine reward memories, either by acute exposure to nicotine (a smoking episode) or by smoking-associated conditioned stimuli (CS). Preclinical studies suggest that drug reward memories can undergo memory reconsolidation after being reactivated, during which they can be weakened or erased by pharmacological or behavioral manipulations. However, translational clinical studies using CS-induced memory retrieval-reconsolidation procedures to decrease drug craving reported inconsistent results.

OBJECTIVE

To develop and test an unconditioned stimulus (UCS)-induced retrieval-reconsolidation procedure to decrease nicotine craving among people who smoke.

DESIGN, SETTING, AND PARTICIPANTS

A translational rat study and human study in an academic outpatient medical center among 96 male smokers (aged 18- 45 years) to determine the association of propranolol administration within the time window of memory reconsolidation (after retrieval of the nicotine-associated memories by nicotine UCS exposure) with relapse to nicotine-conditioned place preference (CPP) and operant nicotine seeking in rats, and measures of preference to nicotine-associated CS and nicotine craving among people who smoke.

INTERVENTION

The study rats were injected noncontingently with the UCS (nicotine 0.15 mg/kg, subcutaneous) in their home cage, and the human study participants administered a dose of propranolol (40 mg, per os; Zhongnuo Pharma).

MAIN OUTCOMES AND MEASURES

Nicotine CPP and operant nicotine seeking in rats, and preference and craving ratings for newly learned and preexisting real-life nicotine-associated CS among people who smoke.

RESULTS

Sixty-nine male smokers completed the experiment and were included for statistical analysis: 24 in the group that received placebo plus 1 hour plus UCS, 23 who received propranolol plus 1 hour plus UCS, and 22 who received UCS plus 6 hours plus propranolol. In rat relapse models, propranolol injections administered immediately after nicotine UCS-induced memory retrieval inhibited subsequent nicotine CPP and operant nicotine seeking after short (CPP, d = 1.72, 95% CI, 0.63-2.77; operant seeking, d = 1.61, 95% CI, 0.59-2.60) or prolonged abstinence (CPP, d = 1.46, 95% CI, 0.42-2.47; operant seeking: d = 1.69, 95% CI, 0.66-2.69), as well as nicotine priming-induced reinstatement of nicotine CPP (d = 1.28, 95% CI, 0.27-2.26) and operant nicotine seeking (d = 1.61, 95% CI, 0.59-2.60) after extinction. Among the smokers, oral propranolol administered prior to nicotine UCS-induced memory retrieval decreased subsequent nicotine preference induced by newly learned nicotine CS (CS1, Cohen d = 0.61, 95% CI, 0.02-1.19 and CS2, d = 0.69, 95% CI, 0.10-1.28, respectively), preexisting nicotine CS (d = 0.57, 95% CI, -0.02 to 1.15), and nicotine priming (CS1, d = 0.82, 95% CI, 0.22-1.41 and CS2, d = 0.78, 95% CI, 0.18-1.37, respectively; preexisting nicotine CS, d = 0.92, 95% CI, 0.31-1.52), as well as nicotine craving induced by the preexisting nicotine CS (d = 0.64, 95% CI, 0.05-1.22), and nicotine priming (d = 1.15, 95% CI, 0.52-1.76).

CONCLUSIONS AND RELEVANCE

In rat-to-human translational study, a novel UCS-induced memory retrieval-reconsolidation interference procedure inhibited nicotine craving induced by exposure to diverse nicotine-associated CS and nicotine itself. This procedure should be studied further in clinical trials.

Acquisition of Conditioned Responses to a Novel Alcohol-Paired Cue in Social Drinkers

OBJECTIVE

This study examined the acquisition of conditioning between novel stimuli and single doses of alcohol in social drinkers. Environmental stimuli present during the consumption of alcohol or other drugs come to elicit conditioned responses that subsequently increase drug seeking. However, relatively few studies have examined the process of acquisition of these conditioned drug responses in human subjects.

METHOD

We used a procedure previously developed to study acquisition of conditioned responses to a methamphetamine-associated cue. In the present study we applied the paradigm to alcohol, pairing de novo neutral cues with alcohol in social drinkers (N = 36). We obtained measures of self-report, behavioral preference, emotional reactivity (assessed using facial electromyography), and attention to specific cues paired with administration of 0.6 g/kg 95% absolute alcohol or placebo.

RESULTS

After conditioning, participants showed an increase in attention toward the alcohol-paired cue, and this increase was associated with ratings of liking the alcohol-containing beverage during the conditioning sessions. In contrast to our previous findings with methamphetamine, the alcohol-paired cue did not elicit changes in emotional reactivity (measured by facial electromyography) or behavioral preference.

CONCLUSIONS

This study extends our previous findings with a stimulant drug to alcohol and highlights possible similarities and differences in conditioning with different classes of drugs. Conditioning with alcohol was less robust than with methamphetamine, but in both cases the conditioning that did occur was related to positive subjective drug response.

When smokers quit: exposure to nicotine and carcinogens persists from thirdhand smoke pollution

BACKGROUND

Over a 6-month period, we examined tobacco smoke pollutants (also known as thirdhand smoke, THS) that remained in the homes of former smokers and the exposure to these pollutants.

METHODS

90 smokers completed study measures at baseline (BL). Measures were repeated among verified quitters 1 week (W1), 1 month (M1), 3 months (M3) and 6 months (M6) following cessation. Measures were analysed for THS pollutants on household surfaces, fingers and in dust (ie, nicotine, tobacco-specific nitrosamines) and for urinary markers of exposure (ie, cotinine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL)).

RESULTS

We observed significant short-term reduction of nicotine on surfaces (BL: 22.2 μg/m², W1: 10.8 μg/m²) and on fingers of non-smoking residents (BL: 29.1 ng/wipe, W1: 9.1 ng/wipe) without further significant changes. Concentrations of nicotine and nicotine-derived nitrosamine ketone (NNK) in dust did not change and remained near BL levels after cessation. Dust nicotine and NNK loadings significantly increased immediately following cessation (nicotine BL: 5.0 μg/m², W1: 9.3 μg/m²; NNK BL: 11.6 ng/m², W1: 36.3 ng/m²) before returning to and remaining at near BL levels. Cotinine and NNAL showed significant initial declines (cotinine BL: 4.6 ng/mL, W1: 1.3 ng/mL; NNAL BL: 10.0 pg/mL, W1: 4.2 pg/mL) without further significant changes.

CONCLUSIONS

Homes of smokers remained polluted with THS for up to 6 months after cessation. Residents continued to be exposed to THS toxicants that accumulated in settled house dust and on surfaces before smoking cessation. Further research is needed to better understand the consequences of continued THS exposure after cessation and the efforts necessary to remove THS.

Acquisition of Conditioning between Methamphetamine and Cues in Healthy Humans

Environmental stimuli repeatedly paired with drugs of abuse can elicit conditioned responses that are thought to promote future drug seeking. We recently showed that healthy volunteers acquired conditioned responses to auditory and visual stimuli after just two pairings with methamphetamine (MA, 20 mg, oral). This study extended these findings by systematically varying the number of drug-stimuli pairings. We expected that more pairings would result in stronger conditioning. Three groups of healthy adults were randomly assigned to receive 1, 2 or 4 pairings (Groups P1, P2 and P4, Ns = 13, 16, 16, respectively) of an auditory-visual stimulus with MA, and another stimulus with placebo (PBO). Drug-cue pairings were administered in an alternating, counterbalanced order, under double-blind conditions, during 4 hr sessions. MA produced prototypic subjective effects (mood, ratings of drug effects) and alterations in physiology (heart rate, blood pressure). Although subjects did not exhibit increased behavioral preference for, or emotional reactivity to, the MA-paired cue after conditioning, they did exhibit an increase in attentional bias (initial gaze) toward the drug-paired stimulus. Further, subjects who had four pairings reported "liking" the MA-paired cue more than the PBO cue after conditioning. Thus, the number of drug-stimulus pairings, varying from one to four, had only modest effects on the strength of conditioned responses. Further studies investigating the parameters under which drug conditioning occurs will help to identify risk factors for developing drug abuse, and provide new treatment strategies.

Extinction of Conditioned Responses to Methamphetamine-Associated Stimuli in Healthy Humans

RATIONALE

Contextual stimuli present during drug experiences become associated with the drug through Pavlovian conditioning and are thought to sustain drug-seeking behavior. Thus, extinction of conditioned responses is an important target for treatment. To date, acquisition and extinction to drug-paired cues have been studied in animal models or drug-dependent individuals, but rarely in non-drug users.

OBJECTIVE

We have recently developed a procedure to study acquisition of conditioned responses after single doses of methamphetamine (MA) in healthy volunteers. Here, we examined extinction of these responses and their persistence after conditioning.

METHODS

Healthy adults (18-35 years; N = 20) received two pairings of audio-visual stimuli with MA (20 mg oral) or placebo. Responses to stimuli were assessed before and after conditioning, using three tasks: behavioral preference, attentional bias, and subjective "liking."

RESULTS

Subjects exhibited behavioral preference for the drug-paired stimuli at the first post-conditioning test, but this declined rapidly on subsequent extinction tests. They also exhibited a bias to initially look towards the drug-paired stimuli at the first post-test session, but not thereafter. Subjects who experienced more positive subjective drug effects during conditioning exhibited a smaller decline in preference during the extinction phase. Further, longer inter-session intervals during the extinction phase were associated with less extinction of the behavioral preference measure.

CONCLUSIONS

Conditioned responses after two pairings with MA extinguish quickly, and are influenced by both subjective drug effects and the extinction interval. Characterizing and refining this conditioning procedure will aid in understanding the acquisition and extinction processes of drug-related conditioned responses in humans.

Altered Appetitive Conditioning and Neural Connectivity in Subjects With Compulsive Sexual Behavior

INTRODUCTION

There has been growing interest in a better understanding of the etiology of compulsive sexual behavior (CSB). It is assumed that facilitated appetitive conditioning might be an important mechanism for the development and maintenance of CSB, but no study thus far has investigated these processes.

AIM

To explore group differences in neural activity associated with appetitive conditioning and connectivity in subjects with CSB and a healthy control group.

METHODS

Two groups (20 subjects with CSB and 20 controls) were exposed to an appetitive conditioning paradigm during a functional magnetic resonance imaging experiment, in which a neutral stimulus (CS+) predicted visual sexual stimuli and a second stimulus (CS-) did not.

MAIN OUTCOME MEASURES

Blood oxygen level-dependent responses and psychophysiologic interaction.

RESULTS

As a main result, we found increased amygdala activity during appetitive conditioning for the CS+ vs the CS- and decreased coupling between the ventral striatum and prefrontal cortex in the CSB vs control group.

CONCLUSION

The findings show that neural correlates of appetitive conditioning and neural connectivity are altered in patients with CSB. The increased amygdala activation might reflect facilitated conditioning processes in patients with CSB. In addition, the observed decreased coupling could be interpreted as a marker for impaired emotion regulation success in this group.

Conditioned cortical reactivity to cues predicting cigarette-related or pleasant images

Through Pavlovian conditioning, reward-associated neutral stimuli can acquire incentive salience and motivate complex behaviors. In smokers, cigarette-associated cues may induce cravings and trigger smoking. Understanding the brain mechanisms underlying conditioned responses to cigarette-associated relative to other inherently pleasant stimuli might contribute to the development of more effective smoking cessation treatments that emphasize the rehabilitation of reward circuitry. Here we measured brain responses to geometric patterns (the conditioned stimuli, CSs) predicting cigarette-related, intrinsically pleasant and neutral images (the unconditioned stimuli, USs) using event-related potentials (ERPs) in 29 never-smokers, 20 nicotine-deprived smokers, and 19 non-deprived smokers. Results showed that during US presentation, cigarette-related and pleasant images prompted higher cortical positivity than neutral images over centro-parietal sensors between 400 and 800ms post-US onset (late positive potential, LPP). The LPP evoked by pleasant images was significantly larger than the LPP evoked by cigarette images. During CS presentation, ERPs evoked by geometric patterns predicting pleasant and cigarette-related images had significantly larger amplitude than ERPs evoked by CSs predicting neutral images. These effects were maximal over right parietal sites between 220 and 240ms post-CS onset and over occipital and frontal sites between 308 and 344ms post-CS onset. Smoking status did not modulate these effects. Our results show that stimuli with no intrinsic reward value (e.g., geometric patterns) may acquire rewarding properties through repeated pairings with established reward cues (i.e., cigarette-related, intrinsically pleasant).

Emotion regulation in heavy smokers: experiential, expressive and physiological consequences of cognitive reappraisal

Emotion regulation dysfunctions are assumed to contribute to the development of tobacco addiction and relapses among smokers attempting to quit. To further examine this hypothesis, the present study compared heavy smokers with non-smokers (NS) in a reappraisal task. Specifically, we investigated whether non-deprived smokers (NDS) and deprived smokers (DS) differ from non-smokers in cognitive emotion regulation and whether there is an association between the outcome of emotion regulation and the cigarette craving. Sixty-five participants (23 non-smokers, 22 NDS, and 20 DS) were instructed to down-regulate emotions by reappraising negative or positive pictorial scenarios. Self-ratings of valence, arousal, and cigarette craving as well as facial electromyography and electroencephalograph activities were measured. Ratings, facial electromyography, and electroencephalograph data indicated that both NDS and DS performed comparably to nonsmokers in regulating emotional responses via reappraisal, irrespective of the valence of pictorial stimuli. Interestingly, changes in cigarette craving were positively associated with regulation of emotional arousal irrespective of emotional valence. These results suggest that heavy smokers are capable to regulate emotion via deliberate reappraisal and smokers’ cigarette craving is associated with emotional arousal rather than emotional valence. This study provides preliminary support for the therapeutic use of reappraisal to replace maladaptive emotion-regulation strategies in nicotine addicts.

Acquisition of responses to a methamphetamine-associated cue in healthy humans: self-report, behavioral, and psychophysiological measures

Drug-associated cues elicit conditioned responses in human drug users, and are thought to facilitate a drug-seeking behavior. Yet, little is known about how these associations are acquired, or about the specificity of the conditioned response modalities. In this study, healthy, nondependent volunteers (N=90) completed a conditioning paradigm in which they received a moderate dose of methamphetamine paired with one stimulus and placebo with another stimulus, each on two separate occasions. Their responses to these cues were measured with a behavioral preference, self-reported 'liking', emotional reactivity, and attentional bias measures, both before and after the conditioning. Following the conditioning procedure, subjects exhibited a behavioral preference, positive emotional reactivity, and attentional bias toward the methamphetamine-associated cue, compared with the placebo stimulus. In addition, subjects who reported greater positive subjective drug effects during the conditioning displayed a more robust conditioning. This work demonstrates that healthy nondependent volunteers readily acquire conditioned responses to neutral stimuli paired with a drug. The procedure has significant value to study individual variation in acquisition of conditioned responses as a possible risk factor for drug taking, and to study the neural basis of conditioned drug responses.

Clarifying the neural basis for incentive salience of tobacco cues in smokers

In functional magnetic resonance imaging (fMRI) studies, smoking cues have been found to elicit increases in brain activity in regions associated with processing rewarding and emotional stimuli. However, most smoking cue studies to date have reported effects relative to neutral control stimuli with no incentive properties, making it unclear whether the observed activation pertains to value in general or the value of cigarettes in particular. The current fMRI study sought to clarify the neural activity reflecting tobacco-specific incentive value versus domain-general incentive value by examining smoking cues, neutral cues, and a third set of cues, monetary cues, which served as an active control condition. Participants were 42 male daily smokers. Compared to neutral cues, significantly greater activation was found in the left ventral striatum in response to tobacco and money cues. Monetary cues also elicited significantly increased activation in the right inferior frontal gyrus and cuneus compared to the other two cue types. Overall, the results suggest that the salience of monetary cues was the highest and, as a result, might have reduced the incentive salience of tobacco cues.

Pain-relief learning in flies, rats, and man: basic research and applied perspectives

Memories relating to a painful, negative event are adaptive and can be stored for a lifetime to support preemptive avoidance, escape, or attack behavior. However, under unfavorable circumstances such memories can become overwhelmingly powerful. They may trigger excessively negative psychological states and uncontrollable avoidance of locations, objects, or social interactions. It is therefore obvious that any process to counteract such effects will be of value. In this context, we stress from a basic-research perspective that painful, negative events are "Janus-faced" in the sense that there are actually two aspects about them that are worth remembering: What made them happen and what made them cease. We review published findings from fruit flies, rats, and man showing that both aspects, respectively related to the onset and the offset of the negative event, induce distinct and oppositely valenced memories: Stimuli experienced before an electric shock acquire negative valence as they signal upcoming punishment, whereas stimuli experienced after an electric shock acquire positive valence because of their association with the relieving cessation of pain. We discuss how memories for such punishment- and relief-learning are organized, how this organization fits into the threat-imminence model of defensive behavior, and what perspectives these considerations offer for applied psychology in the context of trauma, panic, and nonsuicidal self-injury.

Effects of blockade of α4β2 and α7 nicotinic acetylcholine receptors on cue-induced reinstatement of nicotine-seeking behaviour in rats

Exposure to environmental stimuli conditioned to nicotine consumption critically contributes to the high relapse rates of tobacco smoking. Our previous work demonstrated that non-selective blockade of nicotinic acetylcholine receptors (nAChRs) reversed the cue-induced reinstatement of nicotine seeking, indicating a role for cholinergic neurotransmission in the mediation of the conditioned incentive properties of nicotine cues. The present study further examined the relative roles of the two major nAChR subtypes, α4β2 and α7, in the cue-induced reinstatement of nicotine seeking. Male Sprague-Dawley rats were trained to intravenously self-administer nicotine (0.03 mg/kg/infusion, free base) on a fixed-ratio 5 schedule of reinforcement. A nicotine-conditioned cue was established by associating a sensory stimulus with each nicotine infusion. After nicotine-maintained responding was extinguished by withholding the nicotine infusion and its paired cue, reinstatement test sessions were conducted with re-presentation of the cue but without the availability of nicotine. Thirty minutes before the tests, the rats were administered the α4β2-selective antagonist dihydro-β-erythroidine (DHβE) and α7-selective antagonist methyllycaconitine (MLA). Pretreatment with MLA, but not DHβE, significantly reduced the magnitude of the cue-induced reinstatement of responses on the active, previously nicotine-reinforced lever. In different sets of rats, MLA altered neither nicotine self-administration nor cue-induced reinstatement of food seeking. These results demonstrate that activation of α7 nAChRs participates in the mediation of the conditioned incentive properties of nicotine cues and suggest that α7 nAChRs may be a promising target for the development of medications for the prevention of cue-induced smoking relapse.

Neural responses to smoking stimuli are influenced by smokers' attitudes towards their own smoking behaviour

An important feature of addiction is the high drug craving that may promote the continuation of consumption. Environmental stimuli classically conditioned to drug-intake have a strong motivational power for addicts and can elicit craving. However, addicts differ in the attitudes towards their own consumption behavior: some are content with drug taking (consonant users) whereas others are discontent (dissonant users). Such differences may be important for clinical practice because the experience of dissonance might enhance the likelihood to consider treatment. This fMRI study investigated in smokers whether these different attitudes influence subjective and neural responses to smoking stimuli. Based on self-characterization, smokers were divided into consonant and dissonant smokers. These two groups were presented smoking stimuli and neutral stimuli. Former studies have suggested differences in the impact of smoking stimuli depending on the temporal stage of the smoking ritual they are associated with. Therefore, we used stimuli associated with the beginning (BEGIN-smoking-stimuli) and stimuli associated with the terminal stage (END-smoking-stimuli) of the smoking ritual as distinct stimulus categories. Stimulus ratings did not differ between both groups. Brain data showed that BEGIN-smoking-stimuli led to enhanced mesolimbic responses (amygdala, hippocampus, insula) in dissonant compared to consonant smokers. In response to END-smoking-stimuli, dissonant smokers showed reduced mesocortical responses (orbitofrontal cortex, subcallosal cortex) compared to consonant smokers. These results suggest that smoking stimuli with a high incentive value (BEGIN-smoking-stimuli) are more appetitive for dissonant than consonant smokers at least on the neural level. To the contrary, smoking stimuli with low incentive value (END-smoking-stimuli) seem to be less appetitive for dissonant smokers than consonant smokers. These differences might be one reason why dissonant smokers experience difficulties in translating their attitudes into an actual behavior change.

Appraisal frames of pleasant and unpleasant pictures alter emotional responses as reflected in self-report and facial electromyographic activity

Emotional pictures elicit responses across experiential, behavioral and physiological systems. The magnitude of these responses can be modulated by altering one's interpretation of emotional stimuli. Previous studies have indicated that appraisal frames affect subsequent interpretations of upcoming stimuli so as to alter self-reported emotions, ERP activity and autonomic responses. No studies to date have examined the effect of appraisal frames on expressive behaviors as measured by facial EMG. This study aims to test the hypothesis that appraisal frames can alter both emotional experience and facial expression and attempts to examine their effect on the temporal unfolding of facial expressions. Participants (N=20) were exposed to 125 pairs of appraisal frames (neutral or negative/positive) followed by neutral, unpleasant, or pleasant pictures reflecting five conditions: unpleasant-negative, unpleasant-neutral, pleasant-positive, pleasant-neutral and neutral-neutral. Results indicate that the unpleasant-negative compared to the unpleasant-neutral condition led to greater self-reported unpleasantness and arousal, as well as greater corrugator activity, and the pleasant-positive compared to the pleasant-neutral condition led to greater self-reported pleasantness and zygomaticus activity; modulation of facial responses became evident 0.5-1.0s after stimulus onset. These results suggest that appraisal frames effectively alter both emotional experience and facial expressions.

Electrophysiological correlates of associative learning in smokers: a higher-order conditioning experiment

BACKGROUND

Classical conditioning has been suggested to play an important role in the development, maintenance, and relapse of tobacco smoking. Several studies have shown that initially neutral stimuli that are directly paired with smoking are able to elicit conditioned responses. However, there have been few human studies that demonstrate the contribution of higher-order conditioning to smoking addiction, although it is assumed that higher-order conditioning predominates learning in the outside world. In the present study a higher-order conditioning task was designed in which brain responses of smokers and non-smokers were conditioned by pairing smoking-related and neutral stimuli (CS1smoke and CS1neutral) with two geometrical figures (CS2smoke and CS2neutral). ERPs were recorded to all CSs.

RESULTS

Data showed that the geometrical figure that was paired with smoking stimuli elicited significantly larger P2 and P3 waves than the geometrical figure that was paired with neutral stimuli. During the first half of the experiment this effect was only present in smokers whereas non-smokers displayed no significant differences between both stimuli, indicating that neutral cues paired with motivationally relevant smoking-related stimuli gain more motivational significance even though they were never paired directly with smoking. These conclusions are underscored by self-reported evidence of enhanced second-order conditioning in smokers.

CONCLUSIONS

It can be concluded that smokers show associative learning for higher-order smoking-related stimuli. The present study directly shows the contribution of higher-order conditioning to smoking addiction and is the first to reveal its electrophysiological correlates. Although results are preliminary, they may help in understanding the etiology of smoking addiction and its persistence.

Motivation to quit smoking and startle modulation in female smokers: context specificity of smoking cue reactivity

RATIONALE

Cue reactivity and startle reflex modulation paradigms have been used in addiction research to determine the affective motivational state of craving induced by viewing drug-related cues. However, recent studies suggest that cue reactivity and startle reflex modulation in people with addictions can be suppressed, or even reversed, depending on context.

OBJECTIVE

The present study looked at the contextual specificity of smoking cue startle modulation by examining individuals with low and high motivation to quit smoking.

MATERIALS AND METHODS

Emotional modulation of the startle reflex was examined in 32 female smokers exposed to affective stimuli and tobacco cues. The sample was divided into high and low motivation to quit smoking groups using the Processes of Change Questionnaire.

RESULTS

The tobacco cues produced a greater startle magnitude in the group with high motivation to quit smoking than the group with low motivation, which was independent of craving level.

CONCLUSION

Motivation to be abstinent is a relevant contextual factor accounting for variance in cue reactivity in individual smokers.