Roles of "Wanting" and "Liking" in Motivating Behavior: Gambling, Food, and Drug Addictions

Automatic attentional capture by food items in a visuospatial attention task - A study with event-related brain potentials

The incentive sensitization theory suggests that repeated exposure to rewarding substances or food shapes neural circuits to create an attentional bias towards these stimuli. There is ongoing debate about whether attentional capture by such stimuli is an early automatic process or a later stage in the processing cascade. Event-related brain potentials (ERPs) provide a means to pinpoint the timing and location of attentional capture. ERPs were recorded from 28 normal weight healthy women as they attended to the left or right hemifield of a visual display while fixating a central point. Stimuli comprised bars presented left and right of the fixation point simultaneously with the task being to respond to slightly smaller bars on the attended side by button press. The bars appeared superimposed on task-irrelevant distractor stimuli (either food pictures or pictures of non-food objects). The bilateral stimuli elicited a positivity that was largest as posterior sites contralateral to the attended hemifield between 75 and 250 ms. Critically, this contralateral attention effect was enhanced by food distractors on the attended side and diminished by food distractors on the unattended side, demonstrating signs of attention capture by food stimuli as early as 80 ms poststimulus.

A roadmap for transformative translational research on gambling disorder in the UK

The UK has one of the highest rates of recreational gambling in the world. Some vulnerable individuals progressively lose control over gambling and develop at-risk gambling or gambling disorder (GD), characterised by the compulsive pursuit of gambling. GD destroys lives and incurs massive costs to societies, yet only a few treatments are available. Failure to develop a wider range of interventions is in part due to a lack of funding that has slowed progress in the translational research necessary to understand the individual vulnerability to switch from controlled to compulsive gambling. Current preclinical models of GD do not operationalise the key clinical features of the human condition. The so-called "gambling tasks" for non-human mammals almost exclusively assess probabilistic decision-making, which is not real-world gambling. While they have provided insights into the psychological and neural mechanisms involved in the processing of gains and losses, these tasks have failed to capture those underlying real-world gambling and its compulsive manifestation in humans. Here, we highlight the strengths and weaknesses of current gambling-like behaviour tasks and suggest how their translational validity may be improved. We then propose a theoretical framework, the incentive habit theory of GD, which may prove useful for the operationalisation of the biobehavioural mechanisms of GD in preclinical models. We conclude with a list of recommendations for the development of next-generation preclinical models of GD and discuss how modern techniques in animal behavioural experimentation can be deployed in the context of GD preclinical research to bolster the translational pipeline.

Blunted neural response to real-life social reward anticipation in internet gaming disorder: An event-related potential study

Recent research indicates that individuals with Internet gaming disorder (IGD) exhibit impaired social reward processing, evidenced by reduced neural sensitivity to real-life social reward. The aim of the present study is to further investigate the impaired processing of social reward anticipation and reward consumption in individuals with IGD, and explore the relationship between these two components. Using a social incentive delay task with game-related and real-life versions, combined with event-related potential (ERP) technology, we examined 25 individuals with IGD and 25 matched healthy game players. The results showed that, at the behavioral level, individuals with IGD showed significantly slower reaction times to real-life target stimuli compared with game-related target stimuli, which is not observed in healthy controls. At the neural level, the Cue-P3 elicited by real-life incentive cues in individuals with IGD was significantly smaller than that elicited by game-related incentive cues. However, these effects were no longer significant after adding depression and anxiety scores as covariates. There was no significant difference in reward positivity (RewP) elicited between the two types of reward consumption. Furthermore, individuals with IGD showed a positive correlation between Cue-P3 elicited by game-related social incentive cue and RewP elicited by game-related social reward. However, this effect was not observed in the healthy controls. In conclusion, the present study suggests that the blunted allocation of motivated neural attention resources to real-life social incentive cues in individuals with IGD may be the key mechanism underlying their impaired social reward processing. This impairment may be influenced by the higher levels of depression and anxiety symptoms commonly observed in individuals with IGD.

Conditioning- and reward-related dendritic and presynaptic plasticity of nucleus accumbens neurons in male and female sign-tracker rats

For a subset of individuals known as sign-trackers, discrete Pavlovian cues associated with rewarding stimuli can acquire incentive properties and exert control over behaviour. Because responsiveness to cues is a feature of various neuropsychiatric conditions, rodent models of sign-tracking may prove useful for exploring the neurobiology of individual variation in psychiatric vulnerabilities. Converging evidence points towards the involvement of dopaminergic neurotransmission in the nucleus accumbens core (NAc) in the development of sign-tracking, yet whether this phenotype is associated with specific accumbal postsynaptic properties is unknown. Here, we examined dendritic spine structural organisation, as well as presynaptic and postsynaptic markers of activity, in the NAc core of male and female rats following a Pavlovian-conditioned approach procedure. In contrast to our prediction that cue re-exposure would increase spine density, experiencing the discrete lever-cue without reward delivery resulted in lower spine density than control rats for which the lever was unpaired with reward during training; this effect was tempered in the most robust sign-trackers. Interestingly, this same behavioural test (lever presentation without reward) resulted in increased levels of a marker of presynaptic activity (synaptophysin), and this effect was greatest in female rats. Whilst some behavioural differences were observed in females during initial Pavlovian training, final conditioning scores did not differ from males and were unaffected by the oestrous cycle. This work provides novel insights into how conditioning impacts the neuronal plasticity of the NAc core, whilst highlighting the importance of studying the behaviour and neurobiology of both male and female rats.

The gut-brain axis in appetite, satiety, food intake, and eating behavior: Insights from animal models and human studies

The gut-brain axis plays a pivotal role in the finely tuned orchestration of food intake, where both homeostatic and hedonic processes collaboratively control our dietary decisions. This interplay involves the transmission of mechanical and chemical signals from the gastrointestinal tract to the appetite centers in the brain, conveying information on meal arrival, quantity, and chemical composition. These signals are processed in the brain eventually leading to the sensation of satiety and the termination of a meal. However, the regulation of food intake and appetite extends beyond the realms of pure physiological need. Hedonic mechanisms, including sensory perception (i.e., through sight, smell, and taste), habitual behaviors, and psychological factors, exert profound influences on food intake. Drawing from studies in animal models and human research, this comprehensive review summarizes the physiological mechanisms that underlie the gut-brain axis and its interplay with the reward network in the regulation of appetite and satiety. The recent advancements in neuroimaging techniques, with a focus on human studies that enable investigation of the neural mechanisms underpinning appetite regulation are discussed. Furthermore, this review explores therapeutic/pharmacological strategies that hold the potential for controlling food intake.

Mindfulness and mechanisms of attention in a neutral and palatable food context

Introduction

Mindfulness has been associated with benefits on cognitive processes, including attention. However, the exact relationship between mindfulness, components of attention, and the role of reward context has not yet been fully elucidated, which is relevant, especially in the context of addiction. In the current study, we specifically evaluated the relationship between dispositional mindfulness and the balance between voluntary (top-down), and stimulus-driven (bottom-up) attention. In addition, we explored whether the relationship was mediated by asymmetry of frontal brain activity, an index of approach tendencies, and varies as a function of reward context.

Methods

In total, 95 participants (30 male, 65 female) with a mean age of 25.87 (SD = 7.38) participated. Resting-state electrophysiological activity was recorded using EEG, and participants were assessed on dispositional mindfulness, and performed the visuospatial cueing (VSC) task, which indexed voluntary- and stimulus-driven attention in a neutral and palatable food (reward) context. In the endogenous VSC task, a central cue signals the likely location of a subsequent target. The validity effect represents the benefit of valid cueing relative to the costs of invalid cueing in terms of response time.

Results and discussion

Dispositional mindfulness was associated with a reduced validity effect, plausibly reflecting a combination of reduced voluntary attention and increased stimulus-driven attention, irrespective of condition. The relationship between dispositional mindfulness and visuospatial attention could not be explained by asymmetry of frontal brain activity.

Wanting-liking dissociation and altered dopaminergic functioning: Similarities between internet gaming disorder and tobacco use disorder

Background

Although internet gaming disorder (IGD) has been included in the DSM-5 for approximately 10 years, debate remains regarding its existence and classification.

Methods

The current research incorporated three approaches. First, implicit association tests were used to examine for potential dissociation between wanting and liking in IGD. Second, brain features in wanting and liking circuits were tested and compared with tobacco use disorder (TUD) when performing a cue-craving task to explore the neural features of wanting and liking. Third, dopaminergic systems were investigated in IGD and TUD using neuromelanin-sensitive MRI.

Results

The implicit association test results supported a wanting-liking dissociation in IGD participants. Functional MRI data suggested neural correlates underlying wanting-liking dissociation in IGD and TUD participants, with positive correlations suggesting greater dissociation with increasing addiction severity. Neuromelanin results suggest dopaminergic differences in IGD and TUD relative to healthy control participants.

Conclusions

A wanting-liking dissociation in IGD participants suggests gaming motivations in IGD relating to incentive sensitization rather than hedonic responses. The neuromelanin-sensitive MRI results suggest dopaminergic involvement in IGD and TUD. The findings suggest similar brain-behaviour mechanisms for IGD and TUD based on an incentive-sensitization model for addiction, having implications for potential therapeutic strategies and policy-based interventions.

Mindfulness and inhibitory control: Insights from the stop signal task with neutral and reward-associated stimuli

Mindfulness has been linked to enhanced inhibitory control, yet the dynamics of this relationship, especially in reward situations, are not well understood. Our cross-sectional study aimed to explore the relationship between trait mindfulness and a performance measure of inhibitory control as a function of reward context operationalized by stimuli characteristics, and temporal inhibitory demands. Thirty-six individuals aged 19 to 41 filled out the Mindful Attention Awareness Scale (MAAS) and performed a stop signal task (SST), that included both neutral (stone images) and reward-related (money images) stimuli. The SST encompassed four conditions: neutral go/neutral stop, neutral go/reward stop, reward go/neutral stop, and reward go/reward stop, requiring participants to suppress reactions either during or after encountering reward-related stimuli. The relevant index of inhibitory control is the stop signal reaction time (SSRT), a performance measure of inhibitory control. Our findings showed no notable variation in the relationship between the MAAS score and SSRT across the different conditions. However, there was an overall significant effect of MAAS score on SSRT, irrespective of condition. Results may reflect the benefit of mindfulness on inhibitory control after generalized reward exposure.

Acute MK-801 increases measures of both sign-tracking and goal-tracking in male Sprague-Dawley rats

Sign-tracking is a Pavlovian conditioned approach behavior thought to be important in understanding cue-driven relapse to drug use, and strategies for reducing sign-tracking may have some benefit in preventing relapse. A previous study successfully employed the NMDA receptor antagonist MK-801 in preventing the development of sign-tracking (but not goal-tracking) in a conditioned approach task. In this study, we focused on whether MK-801 would have similar effects on previously established sign-tracking behavior. MK-801 was administered after training in a standard sign-/goal-tracking task using a retractable lever as a conditioned stimulus and a sucrose pellet as unconditioned stimulus. It was found that MK-801 increased measures of both sign- and goal-tracking in subjects who had previously learned the task. The NMDA receptor appears to play a complex role in governing behavior related to sign-tracking.

Neurocognitive factors predicting BMI changes from adolescence to young adulthood

OBJECTIVE

The objective of this study was to assess whether inhibitory task performance in adolescence could be prospectively related to weight gain in young adulthood. We proposed that this association would differ according to the BMI group in adolescence.

METHODS

A total of 318 adolescents performed the anti-saccade task, and 530 completed the Stroop test. Accuracy and reaction time were assessed for each incentive type (neutral, loss, and reward) in the anti-saccade task and for each trial type (control and incongruent trials) in the Stroop test. Changes in the BMI z score (∆BMI z score) from adolescence to young adulthood were calculated.

RESULTS

The relationship between the BMI z score and the anti-saccade task accuracy showed an effect on the ∆BMI z score (β = -0.002, p < 0.05). The neutral and loss accuracies were related to ∆BMI z score in the groups with overweight (all β = -0.004, p = 0.05) and obesity (β = -0.006 and β = -0.005, p < 0.01). The interaction between adolescents' BMI z score with control (β = -0.312, p < 0.001) and incongruent (β = -0.384, p < 0.001) trial reaction times showed an effect on the ∆BMI z score. Control (β = 0.730, p = 0.036) and incongruent (β = 0.535, p = 0.033) trial reaction times were related to ∆BMI z score in the group with overweight.

CONCLUSIONS

Our findings support the hypothesis that cognitive vulnerability could predict the BMI gain from adolescence to young adulthood.

Linking drug and food addiction: an overview of the shared neural circuits and behavioral phenotype

Despite a lack of agreement on its definition and inclusion as a specific diagnosable disturbance, the food addiction construct is supported by several neurobiological and behavioral clinical and preclinical findings. Recognizing food addiction is critical to understanding how and why it manifests. In this overview, we focused on those as follows: 1. the hyperpalatable food effects in food addiction development; 2. specific brain regions involved in both food and drug addiction; and 3. animal models highlighting commonalities between substance use disorders and food addiction. Although results collected through animal studies emerged from protocols differing in several ways, they clearly highlight commonalities in behavioral manifestations and neurobiological alterations between substance use disorders and food addiction characteristics. To develop improved food addiction models, this heterogeneity should be acknowledged and embraced so that research can systematically investigate the role of specific variables in the development of the different behavioral features of addiction-like behavior in preclinical models.

Altered motivation states for physical activity and 'appetite' for movement as compensatory mechanisms limiting the efficacy of exercise training for weight loss

Weight loss is a major motive for engaging in exercise, despite substantial evidence that exercise training results in compensatory responses that inhibit significant weight loss. According to the Laws of Thermodynamics and the CICO (Calories in, Calories out) model, increased exercise-induced energy expenditure (EE), in the absence of any compensatory increase in energy intake, should result in an energy deficit leading to reductions of body mass. However, the expected negative energy balance is met with both volitional and non-volitional (metabolic and behavioral) compensatory responses. A commonly reported compensatory response to exercise is increased food intake (i.e., Calories in) due to increased hunger, increased desire for certain foods, and/or changes in health beliefs. On the other side of the CICO model, exercise training can instigate compensatory reductions in EE that resist the maintenance of an energy deficit. This may be due to decreases in non-exercise activity thermogenesis (NEAT), increases in sedentary behavior, or alterations in sleep. Related to this EE compensation, the motivational states associated with the desire to be active tend to be overlooked when considering compensatory changes in non-exercise activity. For example, exercise-induced alterations in the wanting of physical activity could be a mechanism promoting compensatory reductions in EE. Thus, one's desires, urges or cravings for movement-also known as "motivation states" or "appetence for activity"-are thought to be proximal instigators of movement. Motivation states for activity may be influenced by genetic, metabolic, and psychological drives for activity (and inactivity), and such states are susceptible to fatigue-or reward-induced responses, which may account for reductions in NEAT in response to exercise training. Further, although the current data are limited, recent investigations have demonstrated that motivation states for physical activity are dampened by exercise and increase after periods of sedentarism. Collectively, this evidence points to additional compensatory mechanisms, associated with motivational states, by which impositions in exercise-induced changes in energy balance may be met with resistance, thus resulting in attenuated weight loss.

Electrophysiological signature of the interplay between habits and inhibition in response to smoking-related cues in individuals with a smoking habit: An event-related potential study

The rigid, stimulus-bound nature of drug seeking that characterizes substance use disorder (SUD) has been related to a dysregulation of motivational and early attentional reflexive and inhibitory reflective systems. However, the mechanisms by which these systems are engaged by drug-paired conditioned stimuli (CSs) when they promote the enactment of seeking habits in individuals with a SUD have not been elucidated. The present study aimed behaviourally and electrophysiologically to characterize the nature of the interaction between the reflexive and reflective systems recruited by CSs in individuals with a smoking habit. We measured the behavioural performance and associated event-related potentials (ERPs) of 20 individuals with a smoking habit and 20 controls, who never smoked regularly, in a modified Go/NoGo task during which smoking-related CSs, appetitive and neutral pictures, presented either in first or third-person visual perspective were displayed 250 ms before the Go/NoGo cue. We show that smoking-related cues selectively influence early incentive motivation-related attention bias (N2 after picture onset), motor readiness and behavioural inhibition (Go-P3, NoGo-P3 and Pc) of individuals with a smoking habit only when presented from a first-person visual perspective. These data together identify the neural signature of the aberrant engagement of the reflexive and reflective systems during the recruitment of an incentive habit by CSs presented as if they had been response-produced, that is, as conditioned reinforcers.

Disrupted waiting behavior in ADHD: exploring the impact of reward availability and predictive cues

Altered motivational processing is purported to contribute to ADHD symptoms. A stronger preference for immediate over delayed reward is well documented in ADHD. However, little attention has been paid to children's capacity to withhold responding until a "better" reward becomes available, and their actions while waiting. Using a novel computer task, we examine the ability of children with and without ADHD to wait to collect a large reward in the presence of a small available reward. The effects of a reward-predicting cue on response times and response choices are also explored. Data from 136 children (6-12 years), 90 with ADHD and 46 typically developing (TD) children, are included. The children could collect a small immediately available reward or wait to access a larger reward after a variable delay, its imminent availability sometimes signaled by a cue. Subsequent probe trials explored the effects of longer waiting times and disruption of the cue-reward association. As expected, children with ADHD collected the small immediately available reward more often than TD children. Importantly, they were more likely to terminate waiting once commenced, collecting the small reward or attempting to collect the large reward early. The cue decreased their response time but disrupted their waiting when it no longer consistently predicted reward. Children with ADHD were more likely to abandon efforts to wait, especially when wait times were extended and when expected rewards failed to appear. Behavioral interventions for ADHD should take into account reduced waiting capacity that extends beyond children's preference for immediate reward.

Pavlovian-to-Instrumental Transfer across Mental Disorders: A Review

A mechanism known as Pavlovian-to-instrumental transfer (PIT) describes a phenomenon by which the values of environmental cues acquired through Pavlovian conditioning can motivate instrumental behavior. PIT may be one basic mechanism of action control that can characterize mental disorders on a dimensional level beyond current classification systems. Therefore, we review human PIT studies investigating subclinical and clinical mental syndromes. The literature prevails an inhomogeneous picture concerning PIT. While enhanced PIT effects seem to be present in non-substance-related disorders, overweight people, and most studies with AUD patients, no altered PIT effects were reported in tobacco use disorder and obesity. Regarding AUD and relapsing alcohol-dependent patients, there is mixed evidence of enhanced or no PIT effects. Additionally, there is evidence for aberrant corticostriatal activation and genetic risk, e.g., in association with high-risk alcohol consumption and relapse after alcohol detoxification. In patients with anorexia nervosa, stronger PIT effects elicited by low caloric stimuli were associated with increased disease severity. In patients with depression, enhanced aversive PIT effects and a loss of action-specificity associated with poorer treatment outcomes were reported. Schizophrenic patients showed disrupted specific but intact general PIT effects. Patients with chronic back pain showed reduced PIT effects. We provide possible reasons to understand heterogeneity in PIT effects within and across mental disorders. Further, we strengthen the importance of reliable experimental tasks and provide test-retest data of a PIT task showing moderate to good reliability. Finally, we point toward stress as a possible underlying factor that may explain stronger PIT effects in mental disorders, as there is some evidence that stress per se interacts with the impact of environmental cues on behavior by selectively increasing cue-triggered wanting. To conclude, we discuss the results of the literature review in the light of Research Domain Criteria, suggesting future studies that comprehensively assess PIT across psychopathological dimensions.

Orbitofrontal neural dissociation of healthy and unhealthy food reward sensitivity in normal-weight binge eaters

OBJECTIVE

The orbitofrontal cortex (OFC) has been repeatedly found to play an important role in food reward processing and binge eating (BE) episodes. However, most studies have focused mainly on reward-related neural alterations in clinical binge eating patients, with little consideration of preclinical individuals with BE that are more likely to develop from non-clinical individuals to clinical patients in the future. This study aimed to examine whether preclinical binge eaters exhibited OFC-related resting-state functional connectivity (rsFC) in the context of food reward.

METHOD

Binge eaters (BE group, n = 28) and healthy controls (HCs, n = 28) matched for age and body mass index (BMI) underwent rs-fMRI scans and completed self-reported assessment of BE symptoms. Food reward sensitivity was measured using the modified food incentive delay task. Analysis of covariance was used to assess the between-group differences in the medial and lateral OFC (a priori selected regions of interest) connectivity patterns in the context of food reward, while controlling for age, sex, and BMI.

RESULTS

Lower unhealthy food (UF) reward sensitivity was significantly associated with stronger inverse OFC-putamen connectivity for HCs, while the BE group showed no association between UF reward sensitivity and the OFC-putamen connectivity. Higher healthy food (HF) reward sensitivity in the BE group was significantly correlated with stronger positive OFC-middle frontal gyrus and OFC-inferior parietal gyrus connectivity, while the opposite was found for HCs.

CONCLUSIONS

Binge eaters showed less functional synchrony within reward regions contributing to the UF reward sensitivity, but enhanced neural interactions between reward and inhibitory control regions correlated with the HF reward sensitivity. These novel findings may demonstrate the potential orbitofrontal neural dissociation of unhealthy and healthy food reward sensitivity in normal-weight binge eaters.

Seeing attractive faces challenges inhibitory control, especially when mindful

Previous studies have suggested positive effects of mindfulness on inhibitory control (stopping behaviour). However, scarce previous studies suggest the relationship may depend on context. We provide first evidence that inhibitory control is challenged when perceiving attractive faces, especially when being mindful. Specifically, we investigated the relationship between mindfulness and inhibitory control and the moderating role of a social reward context (being exposed to attractive opposite sex faces). Participants (n = 50) between 18–43 years old (M = 25, SD = 5.4) filled out questionnaires assessing standard demographic variables and dispositional mindfulness. Subsequently, they performed a Go/No-go task with a neutral condition and attractive faces condition. Results showed that inhibitory control was challenged in the attractive condition relative to the neutral condition, p = 0.019. Dispositional mindfulness was negatively correlated with inhibitory performance, but only in the attractive faces condition (r = -0.32, p = 0.024). Results did not support a moderating role of gender. Finally, though post-hoc, higher mindfulness was associated with reduced perceived attractiveness of presented faces (r = -0.33, p = 0.019). However, the relationship between mindfulness and reduced inhibitory control could not be explained by mindfulness associated reduced attractiveness. Taken together, results show that mindfulness challenges inhibitory control when perceiving attractive faces. This implies that mindfulness interventions aimed at enhancing inhibitory control, may not render the desired effect in a context of being exposed to attractive faces. Though certainly plausible, it remains an open question whether results generalize to other reward contexts as well.

Individual differences in selective attentional bias for healthy and unhealthy food-related stimuli and social identity as a vegan/vegetarian dissociate "healthy" and "unhealthy" orthorexia nervosa

Previous work identified the operation of an attentional bias (AB) towards healthy food related stimuli among those with increasing tendencies towards orthorexia nervosa (ON) using a modified Stroop task. The current work aimed to replicate and extend our understanding of this effect by incorporating alternative measures of AB (i.e., the dot probe task) and ON (i.e., the Teruel Orthorexia Scale [ToS]) in a sample of self-defined vegans/vegetarians. The theoretical assertion of the ToS is the conceptual broadening of orthorexia with differentiable dimensions - one characterised as a "healthy" preoccupation with healthy food/eating patterns (HeOr) and the other by a more underlying pathology (OrNe). This study also aimed to examine the pattern of responding across these two dimensions according to factors known to predict ON. Eighty-six participants (mean age = 33.0 years; 20 males, 66 females) completed measures of obsessive compulsivity, perfectionism, state/trait anxiety and ToS as well as a dot probe designed to measure AB for healthy and unhealthy-related food stimuli, threat ratings of each of words utilised and perceived identity centrality as a vegan/vegetarianism. Results showed a dissociation of predicted determinants for "healthy" ON (HeOr) and pathological ON (OrNe). HeOr was predicted by increasing identity centrality whereas OrNe was predicted by increased OCD and perfectionism, and increased interference for healthy-related food words (in particular slowed disengagement) and not unhealthy related food words. Threat-related ratings of unhealthy food words was shown to be common across both dimensions. This pattern highlights cognitive and individual differences-based correlates of pathological and non-pathological ON.

Exposure to Depression Memes on Social Media Increases Depressive Mood and It Is Moderated by Self-Regulation: Evidence From Self-Report and Resting EEG Assessments

This study aimed to investigate the effects of depression memes, spread mainly on social media, on depressive mood, and the moderating role of self-regulation based on self-report and electrophysiological (resting EEG frontal alpha asymmetry) assessments. We conducted a semi-online crossover study; first, we collected brain activity data from healthy young adults (n = 32) who were subsequently provided a link to the online experiment. Each participant participated in both the neutral and meme conditions. We also evaluated their level of depressive mood immediately before and after exposure to the stimuli. We further conducted a series of linear mixed effects model analyses and found that depression memes contributed to an increase in depressive symptoms. Specifically, lack of emotional clarity, difficulties in goal-directed behaviors in emotional distress, and impulse control difficulties were linked to greater depressive mood in the case of exposure to depression memes compared with neutral images. However, time interactions were insignificant. These results mainly indicate the centrality of behavioral problems during times of emotional distress caused by depression memes. Lastly, although frontal alpha asymmetry did not predict a change in depressive mood or significantly differ across conditions, lower inhibitory control may result in increased processing of depression memes as negative stimuli. This result is consistent with our self-report results (e.g., impulsivity) as well as other related studies in the literature. However, further research is needed to verify these frontal alpha asymmetry results.

Task-Dependent Effective Connectivity of the Reward Network During Food Cue-Reactivity: A Dynamic Causal Modeling Investigation

Neural reactivity to food cues may play a central role in overeating and excess weight gain. Functional magnetic resonance imaging (fMRI) studies have implicated regions of the reward network in dysfunctional food cue-reactivity, but neural interactions underlying observed patterns of signal change remain poorly understood. Fifty overweight and obese participants with self-reported cue-induced food craving viewed food and neutral cues during fMRI scanning. Regions of the reward network with significantly greater food versus neutral cue-reactivity were used to specify plausible models of task-related neural interactions underlying the observed blood oxygenation level-dependent (BOLD) signal, and a bi-hemispheric winning model was identified in a dynamic causal modeling (DCM) framework. Neuro-behavioral correlations are investigated with group factor analysis (GFA) and Pearson's correlation tests. The ventral tegmental area (VTA), amygdalae, and orbitofrontal cortices (OFC) showed significant food cue-reactivity. DCM suggests these activations are produced by largely reciprocal dynamic signaling between these regions, with food cues causing regional disinhibition and an apparent shifting of activity to the right amygdala. Intrinsic self-inhibition in the VTA and right amygdala is negatively correlated with measures of food craving and hunger and right-amygdalar disinhibition by food cues is associated with the intensity of cue-induced food craving, but no robust cross-unit latent factors were identified between the neural group and behavioral or demographic variable groups. Our results suggest a rich array of dynamic signals drive reward network cue-reactivity, with the amygdalae mediating much of the dynamic signaling between the VTA and OFCs. Neuro-behavioral correlations suggest particularly crucial roles for the VTA, right amygdala, and the right OFC-amygdala connection but the more robust GFA identified no cross-unit factors, so these correlations should be interpreted with caution. This investigation provides novel insights into dynamic circuit mechanisms with etiologic relevance to obesity, suggesting pathways in biomarker development and intervention.

Comprehensive Preclinical Assessment of Sensory, Functional, Motivational-Affective, and Neurochemical Outcomes in Neuropathic Pain: The Case of the Sigma-1 Receptor

Chronic pain remains a major health problem and is currently facing slow drug innovation. New drug treatments should address not only the sensory-discriminative but also functional and motivational-affective components of chronic pain. In a mouse model of neuropathic pain induced by partial sciatic nerve ligation (PSNL), we analyzed sensory and functional-like outcomes by hindpaw mechanical stimulation and automated gait analysis (CatWalk). We characterized over time a reward-seeking task based on diminished motivation for natural reinforcers (anhedonic-like behavior). To differentiate the appetitive ("wanting") and consummatory ("liking") aspects of motivational behavior, we quantified the latency and number of approaches to eat white chocolate, as well as the eating duration and amount consumed. We explored a putative chronic pain-induced dysregulation of monoamine function by measuring monoamine levels in the nucleus accumbens (NAc), a well-known brain reward area. Finally, we investigated the role of sigma-1 receptor (σ₁R) modulation, a nonopioid target, in these multiple dimensions by genetic deletion and pharmacological dose-response studies. After 6 weeks, PSNL increased the approach latency and reduced the consumption of white chocolate in 20-25% of the mice, while around 50-60% had one or the other parameter affected independently. After 10 weeks, sham-operated mice also displayed anhedonic-like behavior. PSNL was associated with reduced extracellular baseline dopamine and increased norepinephrine in the NAc and with a suppression of increased dopamine and serotonin efflux in response to the rewarding stimulus. Genetic and pharmacological blockade of σ₁R relieved these multiple alterations in nerve-injured mice. We comprehensively describe sensory, functional, and depression-like impairment of key components of motivated behavior associated with nerve injury. We provide a neurochemical substrate for the depressed mesocorticolimbic reward processing in chronic pain, with a potentially increased translational value. Our results also highlight σ₁R for the therapeutic intervention of neuropathic pain.

Identifying Player Types to Tailor Game-Based Learning Design to Learners: Cross-sectional Survey using Q Methodology

BACKGROUND

Game-based learning appears to be a promising instructional method because of its engaging properties and positive effects on motivation and learning. There are numerous options to design game-based learning; however, there is little data-informed knowledge to guide the choice of the most effective game-based learning design for a given educational context. The effectiveness of game-based learning appears to be dependent on the degree to which players like the game. Hence, individual differences in game preferences should be taken into account when selecting a specific game-based learning design.

OBJECTIVE

We aimed to identify patterns in students' perceptions of play and games-player types and their most important characteristics.

METHODS

We used Q methodology to identify patterns in opinions on game preferences. We recruited undergraduate medical and dental students to participate in our study and asked participants to sort and rank 49 statements on game preferences. These statements were derived from a prior focus group study and literature on game preferences. We used by-person factor analysis and varimax rotation to identify common viewpoints. Both factors and participants' comments were used to interpret and describe patterns in game preferences.

RESULTS

From participants' (n=102) responses, we identified 5 distinct patterns in game preferences: the social achiever, the explorer, the socializer, the competitor, and the troll. These patterns revolved around 2 salient themes: sociability and achievement. The 5 patterns differed regarding cheating, playing alone, story-telling, and the complexity of winning.

CONCLUSIONS

The patterns were clearly interpretable, distinct, and showed that medical and dental students ranged widely in how they perceive play. Such patterns may suggest that it is important to take students' game preferences into account when designing game-based learning and demonstrate that not every game-based learning-strategy fits all students. To the best of our knowledge, this study is the first to use a scientifically sound approach to identify player types. This can help future researchers and educators select effective game-based learning game elements purposefully and in a student-centered way.

Cultural variability in appraisal patterns for nine positive emotions

Emotions result from evaluations of events, referred to as appraisals. Specific configurations of appraisals have been shown to characterize different emotions, with some variation occurring across cultures. However, appraisal research to date has focused primarily on negative emotions, though recent efforts have started to also examine the appraisal profiles of positive emotions. Cross-cultural work on the appraisals of positive emotions has, however, been scarce. Here, we examine the appraisal profiles of nine positive emotions in the US and China. Using 13 commonly employed appraisal dimensions, we investigated the evaluations of events eliciting amusement, awe, compassion, desire, gratitude, interest, love, pride, and relief. Eighty participants from China and the US recalled events from their own life involving each of these emotions and provided Likert-scale appraisal ratings for each emotional event. Consistent with previous research, we find distinct appraisal patters for each positive emotion. We also, for the first time, demonstrate cultural variations in appraisals of positive emotions. Our study extends existing research by highlighting differences in appraisals of positive emotions across cultures.

Gut peptide regulation of food intake - evidence for the modulation of hedonic feeding

The number of people living with obesity has tripled worldwide since 1975 with serious implications for public health, as obesity is linked to a significantly higher chance of early death from associated comorbidities (metabolic syndrome, type 2 diabetes, cardiovascular disease and cancer). As obesity is a consequence of food intake exceeding the demands of energy expenditure, efforts are being made to better understand the homeostatic and hedonic mechanisms governing food intake. Gastrointestinal peptides are secreted from enteroendocrine cells in response to nutrient and energy intake, and modulate food intake either via afferent nerves, including the vagus nerve, or directly within the central nervous system, predominantly gaining access at circumventricular organs. Enteroendocrine hormones modulate homeostatic control centres at hypothalamic nuclei and the dorso-vagal complex. Additional roles of these peptides in modulating hedonic food intake and/or preference via the neural systems of reward are starting to be elucidated, with both peripheral and central peptide sources potentially contributing to central receptor activation. Pharmacological interventions and gastric bypass surgery for the treatment of type 2 diabetes and obesity elevate enteroendocrine hormone levels and also alter food preference. Hence, understanding of the hedonic mechanisms mediated by gut peptide action could advance development of potential therapeutic strategies for the treatment of obesity and its comorbidities.

The effect of unexpected rewards on decision making in cuttlefish

Despite numerous studies demonstrating the cognitive ability of cephalopods, there is currently no study showing an emotion-like behavior in this group of animals. To examine whether cuttlefish have different internal states, we developed a behavioral paradigm to assess if prior surprised events are able to alter the choice made by cuttlefish. By presenting unexpected food rewards to cuttlefish before the test, we investigated whether the reaction time of choosing between two shrimps, an intuitive response toward the prey without previous learning, at three different levels of discriminative tests (easy, difficult, and ambiguous), are different compared to the one without an unexpected reward. This behavioral paradigm serves to demonstrate whether cuttlefish are aware of ambiguous situations, and their choice outcome and reaction time are dependent of their internal states. The results show that the response latency was significantly shortened in the difficult and ambiguous tests when choosing from two shrimps that are either moderately different in size or similar sizes, respectively, when cuttlefish have received unexpected rewards before the test. These results were compared with tests during which the cuttlefish did not receive any reward in advance. Furthermore, this shortening of latency did not result in a difference in choice outcome during the difficult and ambiguous tests. Interestingly, even when cuttlefish have obtained the expected food rewards or simply made tentacular strike without prey capture each time before test, these prior experiences were sufficient to shorten the response latency in the difficult and ambiguous tests. However, different from the result of unexpected rewards, food consumption alone or prey capture failure did affect the choice outcome during the simple and difficult tests. Taken together, our findings suggest that pre-test treatments of unexpected and expected rewards or simply unsuccessful visual attack seem to induce cuttlefish to adopt different foraging behaviors. This context dependent decision making suggests that cuttlefish’s foraging strategies are influenced by the previously surprised event and their internal states. It also shows a speed-accuracy tradeoff in difficult and ambiguous situations when foraging for prey. This observation may lead to a future investigation of the presence of emotional state in cephalopods.

Dispositional Mindfulness and Inhibitory Control after Perceiving Neutral, Food and Money Related Stimuli

Previous studies have shown that dispositional mindfulness is positively associated with cognitive performance, including the ability to stop behavioral actions (formally called inhibitory control). However, some studies suggest that the relationship may be context dependent. The current study addressed previous limitations and focused on the role of reward context regarding the relationship between mindfulness and inhibitory control. Seventy-five participants (31 men, 44 women) between 18-50 years old (M = 30, SD = 9) were included in the final sample. Participants filled out a self-report measure of mindfulness and performed a stop signal task with three conditions that varied in terms of reward context. In the neutral condition, go stimuli (stimuli to which a response was required) were letters; in the food and money condition, these were pictures of food and money, respectively. Results showed that inhibitory control was reduced in the money condition relative to the neutral condition (p = 0.012). Mindfulness was positively correlated with inhibitory control, but only in the money condition (p = 0.001). However, results might differ when inhibitory control is required while perceiving a learned reward-related stimulus. The latter represents an open question for future research.

The relationship between reward context and inhibitory control, does it depend on BMI, maladaptive eating, and negative affect?

BACKGROUND

Recent studies suggest that higher Body Mass Index (BMI) is associated with reduced inhibitory control in contexts of palatable food. However, due to limitations of previous studies, it remained the question whether this reduction is specific to food contexts, and whether it generalizes to other contexts of reward, such as money. This main question was addressed in the current study. In addition, we explored the effect of maladaptive eating and stress regarding inhibitory control across the contexts that differed in terms of reward.

METHODS

In total, 46 participants between 19 and 50 years old (39% males and 61% females) with an average BMI of 23.5 (SD = 3.9) participated. Participants filled out questionnaires and performed a go/no-go task (indexing inhibitory control) with three conditions (neutral, food, and money condition).

RESULTS

Relatively high (above median) BMI was associated with challenged inhibitory control in the food relative to the neutral context, but not in the money relative to neutral context. Explorative analyses suggested that maladaptive eating and stress were associated with reduced inhibitory control in the food context. Only rumination was associated with reduced inhibitory control in the money context.

CONCLUSIONS

The effects of BMI, maladaptive eating behavior, and stress on inhibitory control were specific to the food context, and did not generalize to a non-intrinsic reward condition, operationalized with money pictures. Our results imply that (research on) interventions directed at improving inhibitory control in relation to overweight and obesity, should consider food-reward context.

Value-based cognition and drug dependency

Value-based decision-making is thought to play an important role in drug dependency. Achieving elevated levels of euphoria or ameliorating dysphoria/pain may motivate goal-directed drug consumption in both drug-naïve and long-time users. In other words, drugs become viewed as the preferred means of attaining a desired internal state. The bias towards choosing drugs may affect one's cognition. Observed biases in learning, attention and memory systems within the brain gradually focus one's cognitive functions towards drugs and related cues to the exclusion of other stimuli. In this narrative review, the effects of drug use on learning, attention and memory are discussed with a particular focus on changes across brain-wide functional networks and the subsequent impact on behaviour. These cognitive changes are then incorporated into the cycle of addiction, an established model outlining the transition from casual drug use to chronic dependency. If drug use results in the elevated salience of drugs and their cues, the studies highlighted in this review strongly suggest that this salience biases cognitive systems towards the motivated pursuit of addictive drugs. This bias is observed throughout the cycle of addiction, possibly contributing to the persistent hold that addictive drugs have over the dependent. Taken together, the excessive valuation of drugs as the preferred means of achieving a desired internal state affects more than just decision-making, but also learning, attentional and mnemonic systems. This eventually narrows the focus of one's thoughts towards the pursuit and consumption of addictive drugs.

The benefits of giving: Effects of prosocial behavior on recovery from stress

Individuals regularly face stress, and the manner in which they cope with that stress is a crucial component in predicting stress recovery. While many engage in self-rewarding behaviors to feel better, these behaviors can come with a cost. The current study tested the effect of engaging in a different behavior after experiencing stress-prosocial behavior. Given the health benefits associated with giving to others, it is plausible that engaging in prosocial behavior is more successful in reducing the psychological and physiological responses to stress. To test this, participants underwent the Trier Social Stress Test and then either sent a gift card to a person of their choosing, received a gift card for themselves, or selected the more aesthetically pleasing gift card. Measures of self-reported mood, heart rate, blood pressure, salivary alpha-amylase, and cortisol were collected throughout the session. While the manipulation did not elicit differences in psychological or hormonal measures, the giving group showed a significantly greater downregulation of their heart rate, diastolic blood pressure, and mean arterial pressure while recovering from the stressor. Additionally, those in the giving group who evidenced greater prosocial sentiment showed a larger reduction in diastolic blood pressure and mean arterial pressure. A follow-up study suggested that these behaviors may be engaging different reward components, as those who gave a gift card reported greater "liking" while those who received a gift card reported greater "wanting". Overall, the findings show that engaging in prosocial behavior following a stressor can help to downregulate physiological stress responses.

Inhibitory Performance in Smokers Relative to Nonsmokers When Exposed to Neutral, Smoking- and Money-Related Pictures

INTRODUCTION

Smoking is associated with significant negative health consequences. It has been suggested that deficient inhibitory control may be implicated in (nicotine) addiction, but its exact role has not yet been elucidated. In the current study, our aim was to investigate the role of inhibitory control in relation to nicotine addiction in contexts that differ in terms of reward.

METHODS

Participants filled out questionnaires and performed a go/no-go task with three conditions. In one condition, the stimuli were neutral color squares, and in the reward conditions, these were smoking-related pictures and money-related pictures, respectively. In total, 43 non-abstinent individuals that smoke and 35 individuals that do not smoke were included in the sample.

RESULTS

The main results showed that individuals that smoke, relative to individuals that do not smoke, had reduced inhibitory control in both reward contexts, relative to a neutral context. The reductions in inhibitory control were mirrored by speeded responses.

CONCLUSIONS

Individuals that smoke seem to present with reduced inhibitory control, which is most pronounced in contexts of reward. Consistent with incentive sensitization theory, the reduced inhibitory control may be (at least partly) due to the heightened approach bias to reward-related stimuli as indicated by the speeded responses.

Peri-adolescent exposure to (meth)amphetamine in animal models

Experimentation with psychoactive drugs is often initiated in the peri-adolescent period, but knowledge of differences in the outcomes of peri-adolescent- vs adult-initiated exposure is incomplete. We consider the existing animal research in this area for (meth)amphetamines. Established for a number of phenotypes, is lower sensitivity of peri-adolescents than adults to acute effects of (meth)amphetamines, including neurotoxic effects of binge-level exposure. More variable are data for long-term consequences of peri-adolescent exposure on motivational and cognitive traits. Moreover, investigations often exclude an adult-initiated exposure group critical for answering questions about outcomes unique to peri-adolescent initiation. Despite this, it is clear from the animal research that (meth)amphetamine exposure during the peri-adolescent period, whether self- or other-administered, impacts brain motivational circuitry and cognitive function, and alters adult sensitivity to other drugs and natural rewards. Such consequences occurring in humans have the potential to predispose toward unfortunate and potentially disastrous family, social and livelihood outcomes.

Eating behavior as a new frontier in memory research

The study of memory is commonly associated with neuroscience, aging, education, and eyewitness testimony. Here we discuss how eating behavior is also heavily intertwined-and yet considerably understudied in its relation to memory processes. Both are influenced by similar neuroendocrine signals (e.g., leptin and ghrelin) and are dependent on hippocampal functions. While learning processes have long been implicated in influencing eating behavior, recent research has shown how memory of recent eating modulates future consumption. In humans, obesity is associated with impaired memory performance, and in rodents, dietary-induced obesity causes rapid decrements to memory. Lesions to the hippocampus disrupt memory but also induce obesity, highlighting a cyclic relationship between obesity and memory impairment. Enhancing memory of eating has been shown to reduce future eating and yet, little is known about what influences memory of eating or how memory of eating differs from memory for other behaviors. We discuss recent advancements in these areas and highlight fruitful research pursuits afforded by combining the study of memory with the study of eating behavior.

Reward processing as a common diathesis for chronic pain and depression

Pain disorders and psychiatric illness are strongly comorbid, particularly in the context of Major Depressive Disorder (MDD). While these disorders account for a significant amount of global disability, the mechanisms of their overlap remain unclear. Understanding these mechanisms is of vital importance to developing prevention strategies and interventions that target both disorders. Of note, brain reward processing may be relevant to explaining how the comorbidity arises, given pain disorders and MDD can result in maladaptive reward responsivity that limits reward learning, appetitive approach behaviours and consummatory response. In this review, we discuss this research and explore the possibility of reward processing deficits as a common diathesis to explain the manifestation of pain disorders and MDD. Specifically, we hypothesize that contextual physical or psychological events (e.g. surgery, divorce) in the presence of a reward impairment diathesis worsens symptoms and results in a negative feedback loop that increases the chronicity and probability of developing the other disorder. We also highlight the implications for treatment and provide a framework for future research.

The self-serving benefits of being a good host: A role for our micro-inhabitants in shaping opioids' function

Opioids are highly efficacious in their ability to relieve pain, but they are liable for abuse, dependence, and addiction. Risk factors to develop opioid use disorders (OUD) include chronic stress, socio-environment, and preexisting major depressive disorders (MDD) and posttraumatic stress disorders (PTSD). Additionally, opioids reduce gut motility, induce loss of gut barrier function, and alter the composition of the trillions of microbes hosted in the gastrointestinal tract, known as the gut microbiota. The microbiota are significant contributors to the reciprocal communication between the central nervous system (CNS) and the gut, termed the gut-brain axis. They have strong influences on their host behaviors, including the ability to cope with stress, sociability, affect, mood, and anxiety. Thus, they are implicated in the etiology of MDD and PTSD. Here we review the latest studies demonstrating that intestinal flora can, directly and indirectly, by affecting sociability levels, responses to stress, and mental state, alter the responses to opioids. It suggests that microbiota can potentially be used to increase the resilience to develop analgesic tolerance and OUD.

Sex differences in vulnerability to addiction

This article reviews evidence for sex differences in vulnerability to addiction with an emphasis on the neural mechanisms underlying these differences. Sex differences in the way that the gonadal hormone, estradiol, interacts with the ascending telencephalic dopamine system results in sex differences in motivated behaviors, including drug-seeking. In rodents, repeated psychostimulant exposure enhances incentive sensitization to a greater extent in females than males. Estradiol increases females' motivation to attain psychostimulants and enhances the value of drug related cues, which ultimately increases their susceptibility towards spontaneous relapse. This, along with females' dampened ability to alter decisions regarding risky behaviors, enhances their vulnerability for escalation of drug use. In males, recent evidence suggests that estradiol may be protective against susceptibility towards drug-preference. Sex differences in the actions of estradiol are reviewed to provide a foundation for understanding how future research might enhance understanding of the mechanisms of sex differences in addiction-related behaviors, which are dependent on estradiol receptor (ER) subtype and the region of the brain they are acting in. A comprehensive review of the distribution of ERα, ERβ, and GPER1 throughout the rodent brain are provided along with a discussion of the possible ways in which these patterns differentially regulate drug-taking between the sexes. The article concludes with a brief discussion of the actions of gonadal hormones on the circuitry of the stress system, including the hypothalamic pituitary adrenal axis and regulation of corticotropin-releasing factor. Sex differences in the stress system can also contribute to females' enhanced vulnerability towards addiction.

Positive Affect: Nature and brain bases of liking and wanting

The positive affect of rewards is an important contributor to well-being. Reward involves components of pleasure 'liking', motivation 'wanting', and learning. 'Liking' refers to the hedonic impact of positive events, with underlying mechanisms that include hedonic hotspots in limbic brain structures that amplify 'liking' reactions. 'Wanting' refers to incentive salience, a motivational process that makes reward cues attractive and able to trigger craving for their reward, mediated by larger dopamine-related mesocorticolimbic networks. Under normal conditions, 'liking' and 'wanting' cohere. However, 'liking' and 'wanting' can be dissociated by alterations in neural signaling, either induced in animal neuroscience laboratories or arising spontaneously in addictions and other affective disorders, which can be detrimental to positive well-being.

Ovarian Hormones and Reward Processes in Palatable Food Intake and Binge Eating

Ovarian hormones are associated with risk for binge eating in women. Recent animal and human studies suggest that food-related reward processing may be one set of neurobiological factors that contribute to these relationships, but additional studies are needed to confirm and extend findings.

Reduced Motivation in Perinatal Fluoxetine-Treated Mice: A Hypodopaminergic Phenotype

Early life is a sensitive period, in which enhanced neural plasticity allows the developing brain to adapt to its environment. This plasticity can also be a risk factor in which maladaptive development can lead to long-lasting behavioral deficits. Here, we test how early-life exposure to the selective-serotonin-reuptake-inhibitor (SSRI), fluoxetine, affects motivation, and dopaminergic signaling in adulthood. We show for the first time that mice exposed to fluoxetine in the early postnatal period exhibit a reduction in effort-related motivation. These mice also show blunted responses to amphetamine and reduced dopaminergic activation in a sucrose reward task. Interestingly, we find that the reduction in motivation can be rescued in the adult by administering bupropion, a dopamine-norepinephrine reuptake inhibitor used as an antidepressant and a smoke cessation aid but not by fluoxetine. Taken together, our studies highlight the effects of early postnatal exposure of fluoxetine on motivation and demonstrate the involvement of the dopaminergic system in this process.SIGNIFICANCE STATEMENT The developmental period is characterized by enhanced plasticity. During this period, environmental factors have the potential to lead to enduring behavioral changes. Here, we show that exposure to the SSRI fluoxetine during a restricted period in early life leads to a reduction in adult motivation. We further show that this reduction is associated with decreased dopaminergic responsivity. Finally, we show that motivational deficits induced by early-life fluoxetine exposure can be rescued by adult administration of bupropion but not by fluoxetine.

Insights into the Neurobiology of Craving in Opioid Use Disorder

Purpose of review

Opioids remain the most potent form of pain relief currently available, yet have a high abuse liability. Here we discuss underlying neurobiological changes in Opioid Use Disorder (OUD) that likely contribute to drug craving, which in turn drives continued drug use and relapse.

Recent findings

Craving has emerged as a strong indicator in drug-seeking and relapse. Studies have demonstrated a number of allostatic changes in circuitry that facilitate learning of drug-stimuli relationships, thereby augmenting cue-triggered drug use and relapse.

Summary

This review will focus on key neurobiological changes in underlying circuitry observed during the initial and continued exposure to opioids that result in an increase in neural-reactivity to drug-related intrinsic and extrinsic drug cues, and to enhanced learning of drug-context correlations. This sensitized learning state may be an indication of the underlying framework that drives craving and ultimately, motivates increased salience of drug cues and drives drug-seeking.

Dance on the Brain: Enhancing Intra- and Inter-Brain Synchrony

Dance has traditionally been viewed from a Eurocentric perspective as a mode of self-expression that involves the human body moving through space, performed for the purposes of art, and viewed by an audience. In this Hypothesis and Theory article, we synthesize findings from anthropology, sociology, psychology, dance pedagogy, and neuroscience to propose The Synchronicity Hypothesis of Dance, which states that humans dance to enhance both intra- and inter-brain synchrony. We outline a neurocentric definition of dance, which suggests that dance involves neurobehavioral processes in seven distinct areas including sensory, motor, cognitive, social, emotional, rhythmic, and creative. We explore The Synchronicity Hypothesis of Dance through several avenues. First, we examine evolutionary theories of dance, which suggest that dance drives interpersonal coordination. Second, we examine fundamental movement patterns, which emerge throughout development and are omnipresent across cultures of the world. Third, we examine how each of the seven neurobehaviors increases intra- and inter-brain synchrony. Fourth, we examine the neuroimaging literature on dance to identify the brain regions most involved in and affected by dance. The findings presented here support our hypothesis that we engage in dance for the purpose of intrinsic reward, which as a result of dance-induced increases in neural synchrony, leads to enhanced interpersonal coordination. This hypothesis suggests that dance may be helpful to repattern oscillatory activity, leading to clinical improvements in autism spectrum disorder and other disorders with oscillatory activity impairments. Finally, we offer suggestions for future directions and discuss the idea that our consciousness can be redefined not just as an individual process but as a shared experience that we can positively influence by dancing together.

Striatal activation to monetary reward is associated with alcohol reward sensitivity

One well-known phenotypic risk factor for the development of alcohol use disorder is sensitivity to the rewarding effects of alcohol. In the present study, we examined whether individuals who are sensitive to alcohol reward are also sensitive to nondrug rewards, thereby reflecting a broader individual difference risk factor. Specifically, we tested the hypothesis that subjective response to acute rewarding effects of alcohol would be related to neural activation during monetary reward receipt relative to loss (in the absence of alcohol). Community-recruited healthy young social drinkers (N = 58) completed four laboratory sessions in which they received alcohol (0.8 g/kg) and placebo in alternating order under double-blind conditions, providing self-report measures of subjective response to alcohol at regular intervals. At a separate visit 1-3 weeks later, they completed a reward-guessing game, the 'Doors' task, during fMRI in a drug-free state. Participants who reported greater motivation (i.e., wanting) to consume more alcohol after a single moderate dose of alcohol also exhibited greater neural activation in the bilateral ventral caudate and the nucleus accumbens during reward receipt relative to loss. Striatal activation was not related to other subjective ratings including alcohol-induced sedation, stimulation, or pleasure (i.e., feeling, liking). Our study is the first to show that measures of alcohol reward are related to neural indices of monetary reward in humans. These results support growing evidence that individual differences in responses to drug and nondrug reward are linked and together form a risk profile for drug use or abuse, particularly in young adults.

Attentional bias and disengagement as a function of Body Mass Index in conditions that differ in anticipated reward

BACKGROUND AND AIMS

Previous studies suggest that attentional bias and disengagement may vary as a function of Body Mass Index (BMI), most notably in a palatable food related context. Though this could indeed represent a food context specific effect, it could also represent a general reward related context effect. In addition, though mindfulness and stress have both been reported to affect attention, it is not yet clear whether these moderate the relationship between BMI and attention as a function of reward context. In the current study we addressed these questions. It was hypothesized that BMI would be positively associated with bias in a food context and money context relative to a neutral context. The inverse was expected for disengagement. It was expected that mindfulness would decrease these relationships and for stress the inverse was expected.

METHODS

In the current online study, eighty-seven participants (24 males and 63 females; age: M = 30.1, SD = 8.3; BMI: M = 24.2, SD = 4.67), filled out questionnaires and completed a visuospatial cueing task measuring attention and disengagement of attention in a neutral, food-related, and money-related condition.

RESULTS

There was no association between BMI and attentional bias. Higher BMI was associated with faster responses to money pictures presented opposite to a cued location as compared to money pictures that did not follow a predictive cue. Our results do not support a clear moderating role of mindfulness and stress.

DISCUSSION AND CONCLUSION

Our results imply faster processing and associated quicker responding to unanticipated reward-related stimuli in individuals with overweight or obesity.

Subjectivity as an Emergent Property of Information Processing by Neuronal Networks

Here, we examine subjectivity and consciousness as emergent properties of the computational complexity of information processing by the brain, rather than metaphysical phenomena. While Psychology concentrates on the emergent properties and Neurobiology examines the properties of the biological substrate, Neurophysiology and Cognitive Neuroscience link the two levels by investigating the mechanisms and processes by which the functions of the brain emerge from the anatomical, cellular and network properties of the nervous system. Our purpose here is not to locate the neural structures that sustain subjectivity or other psychic functions; rather, we examine the operating modes of neurons and neural circuits: they reveal an intrinsically relational quality; sensory elaboration itself proves to be relational and self-centred, necessarily associated with the vital, hedonic, emotional relevance of each experience and external cue, and intrinsically oriented to a behavioral interaction with the latter. The hippocampus adds to this self-centred relational perspective the capability of transforming the identification and the spatial location of objects into a contextualized representation of reality. Since the hippocampus is strongly interconnected with the archaic structures that evaluate vital and hedonic relevance and generate emotional responses, the contextualized information, emotionally colored, is transformed into a comprehensive individual experience. This way, a subjective, self-centred, affectively colored perspective arises in animals due to the intrinsic properties of neuronal circuits in the brain. We conclude that neuronal network processing is strongly characterized per se by a relational and self-centred (subjective) and emotionally colored, motivationally oriented (personal) perspective. The properties and features of neural processing discussed here constitute well-established knowledge in the neuroscientific community. Yet, from a layman’s perception, subjectivity still mysteriously arises in our brain due to the action of consciousness, and in epistemological and philosophical debates, the question often arises as to how consciousness may add the subjective and personal perspective to neural elaboration. The answer appears to be simple: it does not; subjectivity is already there, present ab initio in neuronal processing and not added a posteriori by some other “consciousness” function of unclear neural basis.

Adolescent Exposure to WIN 55212-2 Render the Nigrostriatal Dopaminergic Pathway Activated During Adulthood

BACKGROUND

During adolescence, neuronal circuits exhibit plasticity in response to physiological changes and to adapt to environmental events. Nigrostriatal dopaminergic pathways are in constant flux during development. Evidence suggests a relationship between early use of cannabinoids and psychiatric disorders characterized by altered dopaminergic systems, such as schizophrenia and addiction. However, the impact of adolescent exposure to cannabinoids on nigrostriatal dopaminergic pathways in adulthood remains unclear. The aim of this research was to determine the effects of repeated activation of cannabinoid receptors during adolescence on dopaminergic activity of nigrostriatal pathways and the mechanisms underlying this impact during adulthood.

METHODS

Male Sprague-Dawley rats were treated with 1.2 mg/kg WIN 55212-2 daily from postnatal day 40 to 65. Then no-net flux microdialysis of dopamine in the dorsolateral striatum, electrophysiological recording of dopaminergic neuronal activity, and microdialysis measures of gamma-aminobutyric acid (GABA) and glutamate in substantia nigra par compacta were carried out during adulthood (postnatal days 72-78).

RESULTS

Repeated activation of cannabinoid receptors during adolescence increased the release of dopamine in dorsolateral striatum accompanied by increased population activity of dopamine neurons and decreased extracellular GABA levels in substantia nigra par compacta in adulthood. Furthermore, perfusion of bicuculline, a GABAa antagonist, into the ventral pallidum reversed the increased dopamine neuron population activity in substantia nigra par compacta induced by adolescent cannabinoid exposure.

CONCLUSIONS

These results suggest that adolescent exposure to cannabinoid agonists produces disinhibition of nigrostriatal dopamine transmission during adulthood mediated by decreased GABAergic input from the ventral pallidum.

Habitual Behavior Is Goal-Driven

We address the relation between goal-driven and habitual behaviors. Whereas in recent years the two have been juxtaposed, we suggest that habitual behavior is in fact goal-driven. To support this view, we show that habitual behavior is sensitive to changes in goal properties (reward contingencies), namely goal value and its expectancy of attainment. Whereas adjustment to these properties may be slower for habitual (or overlearned) than for nonhabitual behavior, this is likely due to the routinized (or automatic) nature of such behavior, characterized as it is by reduced attention to its consequences. Furthermore, we show that habitual behavior’s prolonged persistence despite its manifest detachment from the original goal likely stems from its attachment to a different goal. Thus, there is no need to postulate purposeless behavior. The view that habitual behavior is goal-driven offers an integrative account of a considerable body of evidence and is consistent with a functional account of psychological processes.

Sexual cues alter working memory performance and brain processing in men with compulsive sexual behavior

Pornography has been repeatedly at the centre of public attention and has been controversially discussed for a long time. However, little is known about the connection between pornographic stimuli and individual (neuronal) processing of attention and memory. Here, the impact and neural underpinnings of pornographic pictures on working memory processes in a sample of subjects with compulsive sexual behaviour was investigated. Therefore, whilst using functional magnetic resonance imaging (fMRI), a letter n-back task with neutral or pornographic pictures in the background was employed in 38 patients and 31 healthy controls. On the behavioural level, patients were slowed down by pornographic material depending on their pornography consumption in the last week, which was reflected by a higher activation in the lingual gyrus. In addition, the lingual gyrus showed a higher functional connectivity to the insula during processing of pornographic stimuli in the patient group. In contrast, healthy subjects showed faster responses when confronted with pornographic pictures only with high cognitive load. Also, patients showed a better memory for pornographic pictures in a surprise recognition task compared to controls, speaking for a higher relevance of pornographic material in the patient group. These findings are in line with the incentive salience theory of addiction, especially the higher functional connectivity to the salience network with the insula as a key hub and the higher lingual activity during processing of pornographic pictures depending on recent pornography consumption.

Homeostatic regulation of reward via synaptic insertion of calcium-permeable AMPA receptors in nucleus accumbens

The incentive effects of food and related cues are determined by stimulus properties and the internal state of the organism. Enhanced hedonic reactivity and incentive motivation in energy deficient subjects have been demonstrated in animal models and humans. Defining the neurobiological underpinnings of these state-based modulatory effects could illuminate fundamental mechanisms of adaptive behavior, as well as provide insight into maladaptive consequences of weight loss dieting and the relationship between disturbed eating behavior and substance abuse. This article summarizes research of our laboratory aimed at identifying neuroadaptations induced by chronic food restriction (FR) that increase the reward magnitude of drugs and associated cues. The main findings are that FR decreases basal dopamine (DA) transmission, upregulates signaling downstream of the D1 DA receptor (D1R), and triggers synaptic incorporation of calcium-permeable AMPA receptors (CP-AMPARs) in the nucleus accumbens (NAc). Selective antagonism of CP-AMPARs decreases excitatory postsynaptic currents in NAc medium spiny neurons of FR rats and blocks the enhanced rewarding effects of d-amphetamine and a D1R, but not a D2R, agonist. These results suggest that FR drives CP-AMPARs into the synaptic membrane of D1R-expressing MSNs, possibly as a homeostatic response to reward loss. FR subjects also display diminished aversion for contexts associated with LiCl treatment and centrally infused cocaine. An encompassing, though speculative, hypothesis is that NAc synaptic incorporation of CP-AMPARs in response to food scarcity and other forms of sustained reward loss adaptively increases incentive effects of reward stimuli and, at the same time, diminishes responsiveness to aversive stimuli that have potential to interfere with goal pursuit.

Effects of hM4Di activation in CamKII basolateral amygdala neurons and CNO treatment on sensory-specific vs. general PIT: refining PIT circuits and considerations for using CNO

BACKGROUND

Pavlovian stimuli can influence instrumental behaviors via phenomena such as Pavlovian-to-instrumental transfer (PIT). PIT arises via dissociable processes as sensory-specific PIT (SS-PIT) and general PIT. The basolateral amygdala (BLA) mediates SS-PIT, but not general PIT. However, the specific BLA neuronal populations involved are unknown.

AIMS

To determine the contribution of glutamatergic BLA neurons to the expression of SS-PIT and to the recall of sensory-specific properties of stimulus-outcome associations.

METHODS

BLA neurons were transduced with virus containing either GFP or hM4Di, driven by the CamKII promoter. Rats were then tested for SS and general PIT and subsequently for expression of Pavlovian outcome devaluation effects and conditioned taste aversion following injections of vehicle or clozapine-N-oxide (CNO, the hM4Di agonist).

RESULTS

CNO selectively blocked SS-PIT in the hM4Di-expressing group, but not controls, without altering expression of Pavlovian outcome devaluation or sensory-specific taste aversion in either group. Unexpectedly, CNO disrupted general PIT in both groups.

CONCLUSIONS

CamKII BLA neurons mediate the expression of SS-PIT by enabling Pavlovian stimuli to trigger recall of the correct action-outcome associations rather than by mediating recall of the sensory-specific properties of the stimulus-outcome association. Separately, our data demonstrate that CNO alone is sufficient to disrupt affective, but not sensory-specific processes, an effect that was not due to generalized motor disruption. This non-specific effect on general PIT may be related to CNO-induced shifts in internal state. Together, these data identify BLA CamKII neurons as critical for the expression of SS-PIT and reveal important considerations for using CNO to study general affective motivation.