Impulsivity, compulsivity, and top-down cognitive control

Impulsivity in patients with acne excoriee

BACKGROUND

Impulsivity is the tendency to make decisions and act quickly without adequate planning and anticipating risks. Impulsivity is among the core symptoms of many psychiatric disorders. In addition, impulsivity can affect the course of various diseases shaped by behaviors.

AIMS

This study aimed to evaluate the relationship between the presence of acne excoriee and different impulsivity dimensions.

STUDY DESIGN

A case-control study.

METHODS

Thirty patients with acne excoriee (AE+) and 30 acne vulgaris patients without excoriated lesions (AE-) enrolled in this study. Impulsivity was evaluated by The Barratt Impulsivity Scale (BIS). In addition, The Beck Anxiety Inventory, The Beck Depression Inventory, and The Skin Picking Scale were applied to assess the clinical characteristics of the participants.

RESULTS

AE+ patients had higher non-planning subscale scores of BIS than AE- patients in this study. In addition, the acne-picking severity score determined by The Skin Picking Scale was positively correlated with non-planning subscale scores of BIS. There was no significant difference between the groups regarding the Beck Depression Inventory and Beck Anxiety Inventory.

CONCLUSIONS

These results indicate that AE patients have a lack of forethought. In other words, it has been shown that impulsive personality traits, which indicate a lack of planning for the future, may be associated with the acne-picking behavior of the patients.

The development of compulsive coping behaviour is associated with a downregulation of Arc in a Locus Coeruleus neuronal ensemble

Some compulsive disorders have been considered to stem from the loss of control over coping strategies, such as displacement. However, the cellular mechanisms involved in the acquisition of coping behaviours and their subsequent compulsive manifestation in vulnerable individuals have not been elucidated. Considering the role of the locus coeruleus (LC) noradrenaline-dependent system in stress and related excessive behaviours, we hypothesised that neuroplastic changes in the LC may be associated with the acquisition of an adjunctive polydipsic water drinking, a prototypical displacement behaviour, and the ensuing development of compulsion in vulnerable individuals. Thus, male Sprague Dawley rats were characterised for their tendency, or not, to develop compulsive polydipsic drinking in a schedule-induced polydipsia (SIP) procedure before their fresh brains were harvested. A new quantification tool for RNAscope assays revealed that the development of compulsive adjunctive behaviour was associated with a low mRNA copy number of the plasticity marker Arc in the LC which appeared to be driven by specific adaptations in an ensemble of tyrosine hydroxylase (TH)+, zif268- neurons. This ensemble was specifically engaged by the expression of compulsive adjunctive behaviour, not by stress, because its functional recruitment was not observed in individuals that no longer had access to the water bottle before sacrifice, while it consistently correlated with the levels of polydipsic water drinking only when it had become compulsive. Together these findings suggest that downregulation of Arc mRNA levels in a population of a TH+/zif268- LC neurons represents a signature of the tendency to develop compulsive coping behaviours.

Blockade of the orexin 1-receptors and 'cocaine- and amphetamine-regulated transcript' in the nucleus accumbens shell alters impulse control in rats

Impulsivity is a multifaceted construct and alterations in impulsiveness are often associated with psychiatric diseases, including drug addiction and binge eating disorder. Impulse control involves several brain regions. The present study assessed the role of the orexigenic, appetite stimulating neuropeptide orexin (OX) and the anorexigenic, appetite reducing neuropeptide cocaine- and amphetamine-regulated transcript (CART) within the nucleus accumbens shell (NAcSh) in impulse control in rats. The animals were ranked for their trait impulsivity based on a screening in the 5-choice serial reaction time task (5-CSRTT). The rats' performances were analysed after bilateral infusions of the OX 1-receptor antagonist SB-334867 (SB) and CART-antibodies (CART-ABs) into the NAcSh. After SB infusions, there was no change in premature responses observed on average. Further analysis revealed a negative linear correlation between the effect of intra-NAcSh SB infusions on premature responses and trait impulsivity. The effect of SB ranged from an increase, no change to a decrease in premature responses in the individual animals with increasing trait impulsivity. Infusions of CART-ABs led to consistently enhanced impulse control with fewer irrelevant actions, independent of trait impulsivity. These data suggest that both OX, especially OX A, and CART in the NAcSh, can be considered endogenous regulators of impulsive action, dependent on underlying impulsivity in the case of OX and independent from trait impulsivity in the case of CART.

Repeated footshock stress induces an escalation of cocaine self-administration in male and female rats: Role of the cannabinoid receptor 1

Stress is a significant contributor to the development and progression of substance use disorders (SUDs) and is problematic as it is unavoidable in daily life. Therefore, it is important to understand the neurobiological mechanisms that underlie the influence of stress on drug use. We have previously developed a model to examine the contribution of stress to drug-related behavior by administering a stressor, electric footshock stress, daily at the time of cocaine self-administration in rats resulting in an escalation of cocaine intake. This stress-induced escalation of cocaine intake involves neurobiological mediators of stress and reward such as cannabinoid signaling. However, all of this work has been conducted in male rats. Here we test the hypothesis that repeated daily stress can produce an escalation of cocaine in both male and female rats. We further hypothesize that cannabinoid receptor 1 (CB1R) signaling is recruited by repeated stress to influence cocaine intake in both male and female rats. Male and female Sprague-Dawley rats self-administered cocaine (0.5 mg/kg/inf, i.v.) during a modified short-access paradigm wherein the 2-hr access was separated into 4-30 min self-administration blocks separated by 4-5 min drug free period. Footshock stress produced a significant escalation of cocaine intake similarly in both male and female rats. Female stress-escalated rats did display greater time-out non-reinforced responding and greater "front-loading" behavior. In males, systemic administration of a CB1R inverse agonist/antagonist Rimonabant only attenuated cocaine intake in rats with a history of combined repeated stress and cocaine self-administration. However, in females, Rimonabant attenuated cocaine intake in the no stress control group but only at the highest dose of Rimonabant (3 mg/kg, i.p.) suggesting that females show a greater sensitivity to CB1R antagonism. However, female rats with a history of stress showed even greater sensitivity to CB1R antagonism as both doses of Rimonabant (1, 3 mg/kg) attenuated cocaine intake in stress-escalated rats similar to males. Altogether these data demonstrate that stress can produce significant changes in cocaine self-administration and suggests that repeated stress at the time of cocaine self-administration recruits CB1Rs to regulate cocaine-taking behavior across sexes.

Impulsivity Predicts Relapse—but Not Dropout—in Outpatients with SUD: a Longitudinal Study

The objective of this study was to compare performance on a comprehensive impulsivity battery of SUD outpatients who dropout versus those who do not dropout and of abstainers versus relapsers at 3 and 12 months of treatment follow-up. Impulsivity was measured at the start of treatment and adherence and relapse at 3 and 12 months. The participants are 115 outpatients with SUD. Motor impulsivity (Affective Go/No Go), attentional impulsivity (Stroop), delay discounting (Monetary Choice Questionnaire; MCQ), and decision making (Iowa Gambling Task; IGT) were assessed. Impulsivity was not associated with dropout. There were no relationships between treatment outcomes and the MCQ and IGT. Stroop and affective Go-No Go were associated with relapse at 3 and 12 months. Affective motor disinhibition and cognitive disinhibition predict relapse in outpatients. No cognitive aspect of impulsiveness is related to dropout.

Previous experience with delays affects delay discounting in animal model of ADHD

BACKGROUND

ADHD is a disorder where a common symptom is impulsive behaviour, a broad term associated with making sub-optimal choices. One frequently used method to investigate impulsive behaviour is delay discounting, which involves choosing between a small, immediate reinforcer and a delayed, larger one. Choosing the small immediate reinforcer is by itself, however, not sufficient for terming the choice impulsive, as all organisms eventually switch to choosing the small, immediate reinforcer when the delay to the larger reinforcer becomes long. This switch can be termed impulsive only when it occurs more frequently, or at shorter LL delays, than typically observed in normal controls. A poorly understood aspect is how choice is influenced by previous experience with delays. Using an animal model of Attention-Deficit/Hyperactivity Disorder, the Spontaneously Hypertensive Rat, we manipulated the order of exposure to delays in a delay discounting task. Following a preference test, the Ascending group experienced gradually increasing delays between choice and reinforcer while the Descending group were exposed to these delays in reverse order.

RESULTS

The results showed that the Descending group chose the small, immediate reinforcer over the larger delayed to a much larger extent than the Ascending group, and continued to do so even when the delay component was ultimately removed. Strain effects were found in the Ascending group, with SHRs switching to the small, immediate reinforcer earlier than controls as the delay to the larger reinforcer increased.

CONCLUSION

The data suggests that delay discounting is affected by history of exposure to delayed consequences. When reinforcement contingencies are incrementally changed from having no response-reinforcer delay to a long delay, discounting of delayed consequences is gradual. However, a sudden change from no delay to a long delay, without intermediate training, results in a rapid switch to the small, immediate reinforcer option, and this behaviour is somewhat resilient to the shortening and eventual removal of the large reinforcer delay. The implication is that attempting to reduce already existing impulsive behaviour in children with ADHD will require gradual habituation and not sudden changes in reinforcement contingencies.

Core clinical symptoms and suicidal ideation in patients with obsessive-compulsive disorder: A network analysis

INTRODUCTION

Suicidality in obsessive-compulsive disorder (OCD) is underestimated and it is important for clinicians to understand the factors that contribute to suicidal ideation. The present study aimed to estimate a network of the core clinical symptoms of OCD including obsessions, compulsions, and obsessive-compulsive (OC) symptom dimensions, depressive symptoms, and psychological traits, and to examine which symptoms contribute to suicidal ideation in patients with a primary diagnosis of obsessive-compulsive disorder.

METHODS

A total of 444 patients with OCD were assessed with the Yale-Brown Obsessive-Compulsive Scale, the Montgomery-Asberg Depression Rating Scale, and various other measures. Network analysis was conducted to estimate the network of obsessive-compulsive and depressive symptoms, psychological traits including alexithymia and impulsivity, and demographic covariates. Symptoms directly related to suicidal ideation in the network were examined for their relative contribution to suicidal ideation.

RESULTS

Suicidal ideation was directly related to degree of control over compulsive behaviors, distress associated with compulsive behaviors, time spent performing compulsive behaviors, and unacceptable thoughts, along with depressive symptoms and alexithymia. In the network of OC and depressive symptoms the most central symptoms among the former were interference due to compulsive behaviors and interference due to obsessive thoughts, and among the latter were pessimistic thoughts and reported sadness.

CONCLUSION

The findings suggest that along with depressive symptoms and alexithymia, compulsions and unacceptable thoughts dimension may contribute to suicidality, and thus, should be carefully monitored in patients with OCD.

Bank Voles Show More Impulsivity in IntelliCage Learning Tasks than Wood Mice

Impulsivity is a personality trait of healthy individuals, but in extreme forms common in mental disorders. Previous behavioral testing of wild-caught bank voles and wood mice suggested impulsiveness in bank voles. Here, we compared behavioral performance of bank voles and wood mice in tests for response control in the IntelliCage. In the reaction time task, a test similar to the five-choice serial-reaction time task (5CSRTT), bank voles made more premature responses. Impulsivity in the reaction time task was associated with smaller medial habenular nucleus in bank voles. Additional tests revealed reduced behavioral flexibility in the self-paced flexibility task in bank voles, but equal spatial and reversal learning in the chaining/reversal task in both species. Expression of immediate early gene Arc after behavioral testing was low in medial prefrontal cortex, but high in hypothalamic supraoptic and paraventricular nucleus in bank voles. Wood mice showed the opposite pattern. Numbers of Arc-positive cells in the dorsal hippocampus were higher in bank voles than wood mice. Due to continuous behavioral testing (24/7), associations between behavioral performance and Arc were rare. Corticosterone measurements at the end of experiments suggested that IntelliCage testing did not elicit a stress response in these wild rodents. In summary, habenular size differences and altered activation of brain areas after testing might indicate differently balanced activations of cortico-limbic and cortico-hypothalamic circuits in bank voles compared to wood mice. Behavioral performance of bank voles suggest that these rodents could be a natural animal model for investigating impulsive and perseverative behaviors.

ImGo: A Novel Tool for Behavioral Impulsivity Assessment Based on Go/NoGo Tasks

This manuscript aims to present a novel behavioral impulsivity test ImGo, which is suitable for impulsivity assessment in the general population. A series of three studies was conducted to validate its psychometric qualities. In Study 1 we describe the principles of ImGo and verify its test-retest and split-half reliability and its convergent validity with an impulsivity self-report scale and Stop Signal test. In Study 2 we re-analyze the convergent validity of ImGo with a Stop Signal test and examine the potential relationship between ImGo and oculomotor inhibition measured by an Anti-Saccades test. In Study 3 we present a robust research with a large sample size and investigate the discriminant validity of ImGo with tests of other related cognitive and executive processes. Backed by our findings from these studies we can safely claim ImGo is a powerful tool with a good level of reliability (both test-retest and split-half) and validity (convergent and discriminant). Its potential lies in its use in diagnostic and research practice of experts from various countries as the test has already been translated to 9 languages so far. The open-source Hypothesis platform, on which the ImGo test is running, provides the option of both individual and group testing in laboratory conditions as well as remotely through an internet browser.

Optogenetic and pharmacological interventions link hypocretin neurons to impulsivity in mice

Neurons in the lateral hypothalamus expressing the neuropeptide Hypocretin, also known as orexin, are known critical modulators of arousal stability. However, their role in the different components of the arousal construct such as attention and decision making is poorly understood. Here we study Hypocretin neuronal circuit dynamics during stop action impulsivity in a Go/NoGo task in mice. We show that Hypocretin neuronal activity correlates with anticipation of reward. We then assessed the causal role of Hypocretin neuronal activity using optogenetics in a Go/NoGo task. We show that stimulation of Hypocretin neurons during the cue period dramatically increases the number of premature responses. These effects are mimicked by amphetamine, reduced by atomoxetine, a norepinephrine uptake inhibitor, and blocked by a Hypocretin receptor 1 selective antagonist. We conclude that Hypocretin neurons have a key role in the integration of salient stimuli during wakefulness to produce appropriate and timely responses to rewarding and aversive cues.

Assessing the nature of premature responses in the rodent continuous performance test variable intertrial interval schedule using atomoxetine and amphetamine

BACKGROUND

Rodent operant tests that include premature responses (PR) as a measure of impulsivity commonly use variable intertrial interval (vITI) schedules. The rodent continuous performance test (rCPT) is suitable for a vITI schedule.

NEW METHOD

We optimised the analysis for a rCPT vITI schedule with intertrial intervals (ITIs) of 3, 6, and 12 s. Examining the nature of first (FiT) and following touches (FoT) to the blank screen led to a separate quantification of these two behaviours into the first touches level (%FiT) and the following-to-first touches ratio (FoT/FiT).

RESULTS

FiTs occurred more frequently in the 12 s ITIs than at shorter ITIs. Within 12 s ITIs, %FiT was only moderately higher during the last half than the first half, suggesting that long ITIs have a minimal effect on impulsivity, but allow a longer time for its detection. %FiT and the FoT/FiT ratio were uncorrelated. %FiT was negatively correlated with response criterion (C) and uncorrelated with discriminability. Conversely, FoT/FiT ratio was negatively correlated with discriminability, without correlation to C. Atomoxetine decreased %FiT but did not affect FoT/FiT ratio. Amphetamine increased %FiT and decreased the FoT/FiT ratio.

COMPARISON WITH EXISTING METHOD(S)

The results suggest that %FiT is analogous to %PR in related tasks and is a more suitable measure of waiting impulsivity in the rCPT. FoT/FiT ratio is unrelated to %FiT.

CONCLUSIONS

Long ITIs increase the detectability of, but has minimal effect on, waiting impulsivity. %FiT is analogous to %PR in related tasks, while the FoT/FiT ratio is a separate behaviour requiring further characterization.

Neurocognitive Impulsivity in Opiate Users at Different Lengths of Abstinence

The aim of the current study was to examine the effects of length of abstinence on decision making (impulsive choice) and response inhibition (impulsive action) in former opiate users (OU). Participants included 45 OU in early remission [0−12 months of abstinence], 68 OU in sustained remission [>12 months of abstinence], and 68 control participants. Decision making was assessed with the Iowa Gambling Task (IGT), the Cambridge Gambling Task (CGT), and the Monetary Choice Questionnaire (MCQ). Response inhibition was examined with the Stop Signal Task (SST), and the Go/No-Go Task (GNG). Results revealed group differences in decision making under risk (CGT) and ambiguity (IGT), where control participants displayed better decision making compared to OU in early remission. Both groups of former OU were also characterized by higher discounting of delayed rewards (MCQ). Regression analyses revealed minimal effects of length of abstinence on performance on decision-making tasks and no effects on delay discounting. In addition, both OU groups showed reduced action inhibition (GNG) relative to controls and there were no group differences in action cancellation (SST). Length of abstinence had no effect on response inhibition. Overall, our findings suggest that neurocognitive function may not fully recover even with protracted abstinence, which should be addressed by relapse prevention and cognitive remediation programs for OU.

Deleting Snord115 genes in mice remodels monoaminergic systems activity in the brain toward cortico-subcortical imbalances

The neuronal-specific SNORD115 has gathered interest because its deficiency may contribute to the pathophysiology of Prader-Willi syndrome (PWS), possibly by altering post-transcriptional regulation of the gene encoding the serotonin (HTR2C) receptor. Yet, Snord115-KO mice do not resume the main symptoms of PWS, and only subtle-altered A-to-I RNA editing of Htr2c mRNAs was uncovered. Because HTR2C signaling fine-tunes the activity of monoaminergic neurons, we addressed the hypothesis that lack of Snord115 alters monoaminergic systems. We first showed that Snord115 was expressed in both monoaminergic and non-monoaminergic cells of the ventral tegmental area (VTA) and the dorsal raphe nucleus (DRN) harboring cell bodies of dopaminergic and serotonergic neurons, respectively. Measuring the tissue level of monoamines and metabolites, we found very few differences except that the content of homovanillic acid-a metabolite of dopamine-was decreased in the orbitofrontal and prefrontal cortex of Snord115-KO mice. The latter effects were, however, associated with a few changes in monoamine tissue content connectivity across the 12 sampled brain regions. Using in vivo single-cell extracellular recordings, we reported that the firing rate of VTA dopaminergic neurons and DRN serotonergic neurons was significantly increased in Snord115-KO mice. These neural circuit dysfunctions were not, however, associated with apparent defects in binge eating, conditioned place preference to cocaine, cocaine-induced hyperlocomotion or compulsive behavior. Altogether, our multiscale study shows that the absence of Snord115 impacts central monoaminergic circuits to an extent that does not elicit gross behavioral abnormalities.

An addictive disorders severity model: a chained mediation analysis using structural equation modeling

BACKGROUND

The clinical relevance of the degree of severity in addiction disorders supports the need to investigate the variables underlying this aspect of the phenomenon.

OBJECTIVE

This study aimed to explore the relationships between factors that may influence the severity of addiction disorder, with a particular focus on temperamental disinhibition, emotion dysregulation, interpersonal vulnerability, and their interactions.

METHODS

A clinical sample of 502 (77% males and 22% females) was involved. All participants received a DSM-5 clinical diagnosis of "Substance-Related and Addictive Disorders" and were recruited from the Italian National Health System. The collected data were analyzed by implementing a chained mediation model using structural equation modeling.

RESULTS

The statistical appropriateness of the hypothesized latent 4- factors model was confirmed. Specifically, temperamental disinhibition (composed of impulsiveness, compulsiveness, and obsessiveness), emotion dysregulation (composed of affect dysregulation, alexithymia, and dissociation), interpersonal vulnerability (composed of traumatic experiences, preoccupied, avoidant and unresolved attachment), and Addictive Disorders Severity (composed by substance use severity, alcohol use severity, gambling severity, and Internet use severity) were the four factors which have been identified. Furthermore, a total chained mediation model emerged, where emotion dysregulation and interpersonal vulnerability mediated the relationship between temperamental disinhibition and Addictive Disorders Severity.

CONCLUSIONS

Our findings offer a better understanding of the variables associated with addictive disorder severity, providing important indications for therapeutic interventions.

Concurrent measures of impulsive action and choice are partially related and differentially modulated by dopamine D1- and D2-like receptors in a rat model of impulsivity

Impulsivity is a multidimensional construct, but the relationships between its constructs and their respective underlying dopaminergic underpinnings in the general population remain unclear. A cohort of Roman high- (RHA) and low- (RLA) avoidance rats were tested for impulsive action and risky decision-making in the rat gambling task, and then for delay discounting in the delay-discounting task to concurrently measure the relationships among the three constructs of impulsivity using a within-subject design. Then, we evaluated the effects of dopaminergic drugs on the three constructs of impulsivity, considering innate differences in impulsive behaviors at baseline. Risky decision-making and delay-discounting were positively correlated, indicating that both constructs of impulsive choice are related. Impulsive action positively correlated with risky decision-making but not with delay discounting, suggesting partial overlap between impulsive action and impulsive choice. RHAs showed a more impulsive phenotype in the three constructs of impulsivity compared to RLAs, demonstrating the comorbid nature of impulsivity in a population of rats. Amphetamine increased impulsive action and had no effect on risky decision-making regardless of baseline levels of impulsivity, but it decreased delay discounting only in high impulsive RHAs. In contrast, while D₁R and D₃R agonism as well as D_2/3R partial agonism decreased impulsive action regardless of baseline levels of impulsivity, D_2/3R agonism decreased impulsive action exclusively in high impulsive RHAs. Irrespective of baseline levels of impulsivity, risky decision-making was increased by D₁R and D_2/3R agonism but not by D₃R agonism or D_2/3R partial agonism. Finally, while D₁R and D₃R agonism, D_2/3R partial agonism and D₂R blockade increased delay discounting irrespective of baseline levels of impulsivity, D_2/3R agonism decreased it in low impulsive RLAs only. These findings indicate that the acute effects of dopamine drugs were partially overlapping across dimensions of impulsivity, and that only D_2/3R agonism showed baseline-dependent effects on impulsive action and impulsive choice.

Mini-review: The neurobiology of treating substance use disorders with classical psychedelics

The potential of psychedelics to persistently treat substance use disorders is known since the 1960s. However, the biological mechanisms responsible for their therapeutic effects have not yet been fully elucidated. While it is known that serotonergic hallucinogens induce changes in gene expression and neuroplasticity, particularly in prefrontal regions, theories on how specifically this counteracts the alterations that occur in neuronal circuitry throughout the course of addiction are largely unknown. This narrative mini-review endeavors to synthesize well-established knowledge from addiction research with findings and theories regarding the neurobiological effects of psychedelics to give an overview of the potential mechanisms that underlie the treatment of substance use disorders with classical hallucinogenic compounds and point out gaps in the current understanding.

A critical perspective on updating drug memories through the integration of memory editing and brain stimulation

Addiction is a persistent, recurring condition characterized by repeated relapses despite the desire to control drug use or maintain sobriety. The attainment of abstinence is hindered by persistent maladaptive drug-associated memories, which drive drug-seeking and use behavior. This article examines the preliminary evidence supporting the combination of non-invasive brain stimulation (NIBS) techniques and memory editing (or reconsolidation) interventions as add-on forms of treatment for individuals with substance-related disorders (SUD). Studies have shown that NIBS can modestly reduce drug use and craving through improved cognitive control or other undetermined reasons. Memory reconsolidation, a process by which a previously consolidated memory trace can be made labile again, can potentially erase or significantly weaken SUD memories underpinning craving and the propensity for relapse. This approach conveys enthusiasm while also emphasizing the importance of managing boundary conditions and null results for interventions found on fear memory reconsolidation. Recent studies, which align with the state-dependency and activity-selectivity hypotheses, have shown that the combination of NIBS and behavioral interventions holds promise for treating SUD by reducing self-reported and physiological aspects of craving. Effective long-term outcomes for this procedure require better identification of critical memories, a deeper understanding of the brain mechanisms underlying SUD and memory reconsolidation and overcoming any boundary conditions of destabilized memories. This will enable the procedure to be personalized to the unique needs of individual patients.

The translational genetics of ADHD and related phenotypes in model organisms

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent neurodevelopmental disorder resulting from the interaction between genetic and environmental risk factors. It is well known that ADHD co-occurs frequently with other psychiatric disorders due, in part, to shared genetics factors. Although many studies have contributed to delineate the genetic landscape of psychiatric disorders, their specific molecular underpinnings are still not fully understood. The use of animal models can help us to understand the role of specific genes and environmental stimuli-induced epigenetic modifications in the pathogenesis of ADHD and its comorbidities. The aim of this review is to provide an overview on the functional work performed in rodents, zebrafish and fruit fly and highlight the generated insights into the biology of ADHD, with a special focus on genetics and epigenetics. We also describe the behavioral tests that are available to study ADHD-relevant phenotypes and comorbid traits in these models. Furthermore, we have searched for new models to study ADHD and its comorbidities, which can be useful to test potential pharmacological treatments.

Sex differences in addiction-relevant behavioral outcomes in rodents following early life stress

In humans, exposure to early life stress (ELS) is an established risk factor for the development of substance use disorders (SUDs) during later life. Similarly, rodents exposed to ELS involving disrupted mother-infant interactions, such as maternal separation (MS) or adverse caregiving due to scarcity-adversity induced by limited bedding and nesting (LBN) conditions, also exhibit long-term alterations in alcohol and drug consumption. In both humans and rodents, there is a range of addiction-related behaviors that are associated with drug use and even predictive of subsequent SUDs. In rodents, these include increased anxiety-like behavior, impulsivity, and novelty-seeking, altered alcohol and drug intake patterns, as well as disrupted reward-related processes involving consummatory and social behaviors. Importantly, the expression of these behaviors often varies throughout the lifespan. Moreover, preclinical studies suggest that sex differences play a role in how exposure to ELS impacts reward and addiction-related phenotypes as well as underlying brain reward circuitry. Here, addiction-relevant behavioral outcomes and mesolimbic dopamine (DA) dysfunction resulting from ELS in the form of MS and LBN are discussed with a focus on age- and sex-dependent effects. Overall, these findings suggest that ELS may increase susceptibility for later life drug use and SUDs by interfering with the normal maturation of reward-related brain and behavioral function.

Effects of a brief mindfulness meditation practice on Pavlovian-to-instrumental transfer in alcohol use disorder - a pilot study

Introduction

Pavlovian conditioned contextual cues have been suggested to modulate instrumental action and might explain maladaptive behavior such as relapse in participants suffering from alcohol use disorder (AUD). Pavlovian-to-Instrumental transfer (PIT) experimentally assesses the magnitude of this context-dependent effect and studies have shown a larger PIT effect in AUD populations. Taken this into account, a reduction of the influence of cues on behavior seems warranted and one approach that could alter such cue reactivity is mindfulness. Mindfulness-based interventions have been shown to be efficient in the treatment of AUD, but underlying mechanisms are yet to be elucidated. Therefore, we aim at investigating the effect of a brief mindful body scan meditation on the magnitude of the PIT effect in AUD subjects and matched controls.

Methods

Using a randomized within-subjects design, we compared the effect of a short audio guided body scan meditation against a control condition (audio of nature sounds) on PIT in healthy (n = 35) and AUD (n = 27) participants.

Results

We found no differences in PIT effect between healthy and AUD participants as well as between conditions. However, a significant interaction effect points to a decreased PIT effect after body scan meditation in AUD subjects only.

Discussion

These pilot results suggest that AUD might be susceptible to mindfulness-induced changes in PIT, with these findings contributing to entangling the underlying mechanisms of the efficacy of mindfulness-based interventions in AUD. However, further investigation should confirm these preliminary results and the efficacy of mindfulness meditation practice in decreasing the PIT effect.

Impulsivity as a Risk Factor for Addictive Disorder Severity during the COVID-19 Lockdown: Results from a Mixed Quantitative and Qualitative Study

Interindividual differences in personality traits, especially impulsivity traits, are robust risk factors for addictive disorders. However, their impact on addictive disorders during the COVID-19 lockdown remains unknown. This study assessed patients being followed for addictive disorders before the lockdown. We aimed to determine whether impulsivity traits (i.e., negative- and positive urgency) were associated with addictive disorders severity during the lockdowns. We also explored the patients' subjective experiences, focusing on high versus low impulsivity. The quantitative study assessed 44 outpatients consulting for addictive disorders, for impulsivity, emotion regulation, anxiety/depression, and their addictive disorder characteristics, using self-administered questionnaires. In the qualitative study, six patients from the quantitative study were assessed using guided interviews. We observed that higher negative and positive urgencies were associated with addictive disorder severity. The subjective experiences of patients during the lockdowns differed according to their emotion-related impulsivity: high versus low. Low impulsive patients used online technologies more effectively to maintain follow-up, with more positive reappraisal. In contrast, highly impulsive patients reverted more frequently to self-medication with substances and/or behaviors, more social isolation, and found coping with negative emotions more challenging. Overall, the patient's ability to cope with stressful events, like the COVID-19 lockdown, depended on their emotion-related impulsivity.

Analytic Background in the Neuroscience of the Potential Project "Hippocrates"

This paper reviews the principles identified in analytic neuroscience that could be used in the setup of an international project, "Hippocrates" (H-project), named after the author of the endocrine theory of temperaments. The H-project can aim to summarize the findings in functional neurochemistry of consistent behavioural patterns (CBPs) in health (such as temperament traits) and psychopathology (symptoms of psychiatric disorders); to have systematically structured neurochemical investigations; to have an analysis of CBPs that include all ranges of behavioural histories and to have these modules complemented by regional contrasts related to climate, diets and other bio-environmental factors. The review highlights the benefits of constructivism and illustrates the contrast between constructivism and current approaches in terms of analytic and methodological aspects. (1) "Where" the neurochemical biomarkers should be measured: the review expands the range of needed measurements to out-of-brain systems, including environmental factors, and explores the concept of Specialized Extended Phenotype. (2) "What" should be measured but is missing: the review points to the need for measurement of the "Throw & Catch" neurochemical relays; behavioural and neuronal events contributing to the consistency of the CBPs but not documented in measurements. (3) Structuring the H-project's setup: the paper briefly describes a proposed earlier neurochemical framework, Functional Ensemble of Temperament that that accommodates the neurochemical continuum between temperament and symptoms of psychiatric disorders. This framework is in line with documented "Throw & Catch" neurochemical relays and can also be used to organize data about the personal and professional history of an individual.

Dissociable behavioural signatures of co-existing impulsivity and apathy in decision-making

Apathy and impulsivity are expressed in a wide range of neuropsychiatric disorders, and, to a less severe extent, in healthy people too. Although traditionally considered to be opposite extremes of a single motivational spectrum, recent epidemiological questionnaire-based data suggest that both traits can in fact co-exist within the same individual. Here, we sought to investigate the relationship between these constructs in healthy people within a controlled task environment that examines the ability to make a decision under temporal uncertainty and measures the vigour of the response. Sixty participants performed a new version of the Traffic Light Task and completed self-report questionnaire measures of apathy and impulsivity. The task required individuals to make rapid decision-making for time-sensitive reward by squeezing a hand-held dynamometer as quickly as possible after a predictable event occurred (a traffic light turning green). Although apathy and impulsivity were positively correlated in questionnaire assessments, the two traits were associated with distinct behavioural signatures on the task. Impulsivity was expressed as an inflexible tendency to generate rapid anticipatory responses, regardless of cost-benefit information. Apathy, on the other hand, was associated with a blunted effect of reward on response vigour. These findings reveal how apathy and impulsivity are related to distinct dimensions of goal-directed behaviour, explaining how these traits might co-exist in the same individuals.

Negative valence system as a relevant domain in compulsivity: review in a preclinical model of compulsivity

Compulsive behavior is observed in different neuropsychiatric disorders such as Obsessive-Compulsive Disorder (OCD), anxiety, phobia, schizophrenia and addiction. Compulsivity has been proposed as a transdiagnostic symptom, where the Research Domain Criteria (RDoC) strategy could help to understand its neuropsychological basis for a better understanding, and development of therapeutic and preventive strategies. However, research on compulsivity has been focused on the cognitive control domain, and the contribution of an altered negative valence system has been less considered. In this review, we collate the main findings in an animal model of compulsivity, the high drinker (HD) rats selected by Schedule-Induced Polydipsia (SIP) regarding these two research domains. This preclinical model of compulsivity has shown a phenotype characterized by a lack of behavioral inhibition, impulsive decision-making and cognitive inflexibility. Moreover, the results in compulsive HD rats, suggests that there is also a relevant alteration in the emotional dimension, linked to the negative valence system domain, as for example by: the increased perseverative responses in a withdrawal condition, associated with the behavioral construct of frustrative non-reward; and an inhibition or extinction deficit in memory retrieval associated with an alteration in the behavioral response to sustained threat. However, the precise nature of the link between these shared altered domains, cognitive control and negative valence system, remains unknown. These results point towards relevant behavioral aspects of the compulsive phenotype that should be taken into account when studying the vulnerability to compulsivity that could help in the development of a better transdiagnostic assessment, preventive and therapeutic strategies.

Neural Signatures of Error Processing in Depressed Adolescents with Comorbid Non-Suicidal Self-Injury (NSSI)

Non-suicidal self-injury (NSSI), as a highly prevalent psychiatric symptom in adolescents and young adults, is defined as the deliberate destruction of body tissue without suicidal intent. Impulsivity and dysfunctional response inhibition have been suggested to play a central role in adolescents' vulnerability to self-harm. To investigate the potentially distinct neurobiology of NSSI, we used a well-established Go/No Go task in which activation of the inferior frontal gyrus (IFG) and dorsal anterior cingulate cortex (dACC) is interpreted as a neural correlate of processing failed response inhibition. Task-based functional magnetic resonance imaging data were obtained from 14 adolescents with a diagnosis of major depression and a history of NSSI (MD-NSSI), 13 depressed adolescents without NSSI (MD-only), and 14 healthy controls (HC). In line with hypotheses of dysfunctional response inhibition, we observed increased rates of commission errors in MD-NSSI along with significantly reduced error-related activations of the dACC and IFG. Intact response inhibition, as reflected by low commission error rates not different from HC, was observed in MD-only, along with increased activation of the error-processing network. Our findings support the hypothesis of a distinct neurobiological signature of NSSI. Further research on biomarkers of NSSI could focus on behavioral and neural correlates of failed response inhibition.

Behavioral phenotypes revealed during reversal learning are linked with novel genetic loci in diversity outbred mice

Impulsive behavior and impulsivity are heritable phenotypes that are strongly associated with risk for substance use disorders. Identifying the neurogenetic mechanisms that influence impulsivity may also reveal novel biological insights into addiction vulnerability. Our past studies using the BXD and Collaborative Cross (CC) recombinant inbred mouse panels have revealed that behavioral indicators of impulsivity measured in a reversal-learning task are heritable and are genetically correlated with aspects of intravenous cocaine self-administration. Genome-wide linkage studies in the BXD panel revealed a quantitative trait locus (QTL) on chromosome 10, but we expect to identify additional QTL by testing in a population with more genetic diversity. To this end, we turned to Diversity Outbred (DO) mice; 392 DO mice (156 males, 236 females) were phenotyped using the same reversal learning test utilized previously. Our primary indicator of impulsive responding, a measure that isolates the relative difficulty mice have with reaching performance criteria under reversal conditions, revealed a genome-wide significant QTL on chromosome 7 (max LOD score = 8.73, genome-wide corrected p<0.05). A measure of premature responding akin to that implemented in the 5-choice serial reaction time task yielded a suggestive QTL on chromosome 17 (max LOD score = 9.14, genome-wide corrected <0.1). Candidate genes were prioritized (2900076A07Rik, Wdr73 and Zscan2) based upon expression QTL data we collected in DO and CC mice and analyses using publicly available gene expression and phenotype databases. These findings may advance understanding of the genetics that drive impulsive behavior and enhance risk for substance use disorders.

Neural basis of anticipation and premature impulsive action in the frontal cortex

Planning motor actions can improve behavioral performance; however, it can also lead to premature actions. Although the anterior lateral motor cortex (ALM) is known to be important for correct motor planning, it is currently unknown how it contributes to premature impulsive motor output. This was addressed using whole-cell voltage recordings from layer 2/3 pyramidal neurons within the ALM while mice performed a cued sensory association task. Here, a robust voltage response was evoked during the auditory cue, which was greater during incorrect premature behavior than during correct performance in the task. Optogenetically suppressing ALM during the cued sensory association task led to enhanced behavior, with fewer, and more delayed, premature responses and faster correct responses. Taken together, our findings extend the current known roles of the ALM, illustrating that ALM plays an important role in impulsive behavior by encoding and influencing premature motor output.

The Relationship between Emotion Regulation (ER) and Problematic Smartphone Use (PSU): A Systematic Review and Meta-Analyses

Emotion Dysregulation (ED) and Problematic Smartphone Use (PSU) are two rising global issues requiring further understanding on how they are linked. This paper aims to summarize the evidence pertaining to this relationship. Five databases were systematically searched for published literature from inception until 29 March 2021 using appropriate search strategies. Each study was screened for eligibility based on the set criteria, assessed for its quality and its level of evidence was determined. The Comprehensive Meta-Analysis software program (CMA) was employed to run further analyses of the data. Twenty-one studies were included in the systematic review. Nine studies with extractable data for meta-analysis had high across-studies heterogeneity, hence subgroup analyses were performed that confirmed a significant moderate positive correlation between ED and PSU (pooled correlation coefficient, r = 0.416 (four studies, n = 1462) and r = 0.42 (three studies, n = 899), respectively) and a weak positive correlation between "expressive suppression" and PSU (pooled correlation coefficient, r = 0.14 (two studies, n = 608)). Meta-regression analysis showed a stronger correlation between ED and PSU (R2 = 1.0, p = 0.0006) in the younger age group. Further studies to establish and explore the mechanisms that contribute towards the positive link between ED and PSU are required to guide in the planning of targeted interventions in addressing both issues.

The relationships between social media exposure, food craving, cognitive impulsivity and cognitive restraint

BACKGROUND

Young adults are increasingly exposed to social media and their image/video-based activities. They use these platforms to share images, videos and advice in different fields like food and nutrition with: recipe ideas, nutritional opinions or specific diets. Along with the rise of digital technologies, the prevalence of eating disorders in young adults continues to grow. The present study analyzes the psychological and eating processes through which exposure to social media may lead to the development of food craving and problematic eating behaviors.

METHODS

A total of 103 young adult men (n = 15) and women (n = 88) answered questionnaires measuring their impulsivity (Barratt Impulsiveness Scale), eating habits (Three-Factor Eating Questionnaire), food craving (Food Cravings Questionnaire-Trait-reduced), and time exposure to social media.

RESULTS

The results showed two significant serial mediations. We found a correlational link between time exposure to social media and food craving scores. This positive relation is indirectly mediated by cognitive impulsivity. We also found a positive correlation between cognitive impulsivity and food craving scores that was mediated by cognitive restraint.

CONCLUSION

A better understanding of the existing links between social media, food craving and eating behaviors such as cognitive restraint could help researchers and clinicians to better guide young adults in their use and appropriation of social media food contents.

The orphan receptor GPR88 controls impulsivity and is a risk factor for Attention-Deficit/Hyperactivity Disorder

The neural orphan G protein coupled receptor GPR88 is predominant in the striatum and cortex of both rodents and humans, and considered a potential target for brain disorders. Previous studies have shown multiple behavioral phenotypes in Gpr88 knockout mice, and human genetic studies have reported association with psychosis. Here we tested the possibility that GPR88 contributes to Attention Deficit Hyperactivity Disorder (ADHD). In the mouse, we tested Gpr88 knockout mice in three behavioral paradigms, best translatable between rodents and humans, and found higher motor impulsivity and reduced attention together with the reported hyperactivity. Atomoxetine, a typical ADHD drug, reduced impulsivity in mutant mice. Conditional Gpr88 knockout mice in either D1R-type or D2R-type medium spiny neurons revealed distinct implications of the two receptor populations in waiting and stopping impulsivity. Thus, animal data demonstrate that deficient GPR88 activity causally promotes ADHD-like behaviors, and identify circuit mechanisms underlying GPR88-regulated impulsivity. In humans, we performed a family-based genetic study including 567 nuclear families with DSM-IV diagnosis of ADHD. There was a minor association for SNP rs2036212 with diagnosis, treatment response and cognition. A stronger association was found for SNP rs2809817 upon patient stratification, suggesting that the T allele is a risk factor when prenatal stress is involved. Human data therefore identify GPR88 variants associated with the disease, and highlight a potential role of life trajectories to modulate GPR88 function. Overall, animal and human data concur to suggest that GPR88 signaling should be considered a key factor for diagnostic and treatment of ADHD.

Developmental changes in impulse control: Trial-by-trial EMG dissociates the evolution of impulse strength from its subsequent suppression

Goal-oriented behavior can be disrupted by irrelevant information that automatically activates incorrect responses. While behavioral errors reveal response capture in such situations, they are only the tip of the iceberg. Additional subliminal activations of the incorrect responses (partial errors) can be revealed on correctly responded trials thanks to electromyography (EMG). In the current study, for the first time, EMG recorded in children was combined with distributional analyses. This allowed to investigate the properties of incorrect response activations and to highlight developmental changes in impulse control. A sample of 114 children aged 6-14 years was studied. Children performed a Simon task in which the irrelevant stimulus-position automatically activates a response that might be compatible or incompatible with the correct one. On incompatible trials, the automatic response activation must be overcome by controlled response selection. As previously observed in adults, our approach revealed the presence of an automatic EMG activation of the incorrect response elicited by the irrelevant stimulus dimension. Further, it revealed another independent source at the origin of incorrect response activations: the tendency to guess for response alternation. Both sources increased the frequency of early incorrect EMG activations, indicating impulsive responding. In addition, the influence of both sources decreased with increasing age. Thus, development is marked by improved ability to manage distractibility on the one hand and decreased tendency to rely on a guessing strategy on the other.

Inpatient suicide in psychiatric settings: Evaluation of current prevention measures

The risk of suicide in psychiatric hospitals is 50 times higher than in the general population, despite patient safety being a priority for any hospital. However, to date, due to the complexity of assessing suicide risk, there has been no consensus on the suicide prevention measures that should be in place in hospitals. The aim of this work is: To provide an overview of the progress that has been made in the field of inpatient suicide prevention in recent years; discuss the problems that remain; and suggest potential future developments. As new clinical dimensions (notably anhedonia, psychological pain and hopelessness) develop, they should become new therapeutic targets. Team training (like the Gatekeeper Training Program) and the latest advances in suicide risk assessment (such as the Collaborative Assessment and Management of Suicidality) should be implemented in psychiatric wards. Suicide prevention plans (e.g., ASSIP, SAFE-T, etc.) represent easy-to-administer, low-cost interventions. The Mental Health Environment of Care Checklist has been proven effective to reduce suicide risk at hospitals. Furthermore, the types of psychotherapy recommended to reduce suicide risk are cognitive behavioral therapy (CBT) and dialectical behavioral therapy (DBT). There are several pharmacological treatments for suicide risk, such as lithium and clozapine, which have been shown to be effective in the long term, as well as ketamine and esketamine, which are more effective in the short term. Following some encouraging recent results, buprenorphine may also be proposed to patients with a suicide risk. Triple chronotherapy rapidly improves depressive symptoms over 9 weeks. Regarding brain stimulation techniques, rTMS has proven to be effective in alleviating multiple dimensions of suicidality.

The roles of behavioral inhibition/activation systems and impulsivity in problematic smartphone use: A network analysis

Background

Behavioral inhibition/activation systems (BIS/BAS) and impulsivity are associated with problematic smartphone use (PSU). However, no studies to date have explored how the subdomains of BIS/BAS and the dimensions of impulsivity relate to the components of PSU in a joint framework. This study aimed to examine the relationships between the three constructs at a fine-grained level and identify the central nodes and bridge nodes of their relationships using network analysis.

Methods

A regularized partial correlation network of PSU, BIS/BAS, and impulsivity communities was estimated to investigate the connections between variables and determine the expected influence and bridge expected influence for each variable based on data from 325 Chinese adults. PSU, BIS/BAS, and impulsivity were assessed using the Smartphone Application-Based Addiction Scale (SABAS), BIS/BAS scales, and Barratt Impulsiveness Scale-Version 11 (BIS-11), respectively.

Results

In addition to connections within each community, network analysis revealed that there were connections between different communities, especially connections to PSU. I2 "motor impulsivity" was strongly associated with PSU2 "conflict" and PSU6 "relapse"; BASR "BAS-reward responsiveness" was strongly associated with PSU5 "withdrawal." Nodes BASR "BAS-reward responsiveness" and PSU6 "relapse" were the most central variables, while nodes BASR "BAS-reward responsiveness" and I2 "motor impulsivity" were the strongest bridge variables.

Conclusion

The connections between the subdomains of BIS/BAS and the components of PSU and between the dimensions of impulsivity and the components of PSU may be particularly important in the development and maintenance of PSU. The central variables identified here, along with the bridge variables, could be promising and effective targets for the prevention and intervention of PSU.

Risk for bipolar spectrum disorders associated with positive urgency and orbitofrontal cortical grey matter volume

Bipolar spectrum disorders (BSDs) are associated with reward hypersensitivity, impulsivity, and structural abnormalities within the brain's reward system. Using a behavioral high-risk study design based on reward sensitivity, this paper had two primary objectives: 1) investigate whether elevated positive urgency, the tendency to act rashly when experiencing extreme positive affect, is a risk for or correlate of BSDs, and 2) examine the nature of the relationship between positive urgency and grey matter volume in fronto-striatal reward regions, among individuals at differential risk for BSD. Young adults (ages 18-28) screened to be moderately reward sensitive (MReward; N = 42), highly reward sensitive (HReward; N = 48), or highly reward sensitive with a lifetime BSD (HReward + BSD; N = 32) completed a structural MRI scan and the positive urgency subscale of the UPPS-P scale. Positive urgency scores varied with BSD risk (MReward < HReward < HReward + BSD; ps≤0.05), and positive urgency interacted with BSD risk group in predicting lateral OFC volume (p <.001). Specifically, the MReward group showed a negative relationship between positive urgency and lateral OFC volume. By contrast, there was no relationship between positive urgency and lateral OFC grey matter volume among the HReward and HReward + BSD groups. The results suggest that heightened trait positive urgency is a pre-existing vulnerability for BSD that worsens with illness onset, and there is a distinct relationship between positive urgency and lateral OFC volume among individuals at high versus low risk for BSD. These findings have implications for understanding the expression and development of impulsivity in BSDs.

Comparison of the acute effects of Tai chi versus high-intensity interval training on inhibitory control in individuals with substance use disorder

Objective

The purpose of this study is to investigate the effects of a single session of Tai chi (TC) exercise and high-intensity interval training (HIIT) on inhibitory control in individuals with substance use disorder (SUD).

Methods

A total 47 males with methamphetamine dependence were recruited from a compulsory drug rehabilitation center; participation in this study was voluntary. The participants were randomly assigned to the TC group or the HIIT group, and computer-based Go/No-go and Stroop tasks were used to assess inhibitory control in an indoor setting prior to and following exercise. Independent sample t-test was applied for baseline comparison of continuous variables, while analysis of variance was applied to test differences in the effect of each intervention before and after a single session of exercise.

Results

In Go/No-go test, the reaction time of the TC and HIIT groups in the post-test was shorter than that at the baseline, and the response accuracy of the post-test were higher than that of the baseline. In the Stroop task, the reaction time of two groups in the post-test was shorter than that at the baseline; while, greater improvement in response accuracy was observed in HIIT group in the post-test than that of the baseline.

Conclusion

Both TC and HIIT can promote inhibitory control in individuals with SUD. Compared with the TC group, the HIIT group showed greater improvements in response accuracy. These findings demonstrate the potential of TC and HIIT in improving cognition in SUD.

Clinical trial registration

[http://www.chictr.org.cn/], identifier [ChiCTR1900022158].

A Meta-Analysis of fMRI Studies of Youth Cannabis Use: Alterations in Executive Control, Social Cognition/Emotion Processing, and Reward Processing in Cannabis Using Youth

Background: Adolescent cannabis use (CU) is associated with adverse health outcomes and may be increasing in response to changing cannabis laws. Recent imaging studies have identified differences in brain activity between adult CU and controls that are more prominent in early onset users. Whether these differences are present in adolescent CU and relate to age/developmental stage, sex, or cannabis exposure is unknown. Methods: A systematic review and subsequent effect-size seed-based d mapping (SDM) meta-analysis were conducted to examine differences in blood-oxygen-level-dependent (BOLD) response during fMRI studies between CU and non-using typically developing (TD) youth. Supplemental analyses investigated differences in BOLD signal in CU and TD youth as a function of sex, psychiatric comorbidity, and the dose and severity of cannabis exposure. Results: From 1371 citations, 45 fMRI studies were identified for inclusion in the SDM meta-analysis. These studies compared BOLD response contrasts in 1216 CU and 1486 non-using TD participants. In primary meta-analyses stratified by cognitive paradigms, CU (compared to TD) youth showed greater activation in the rostral medial prefrontal cortex (rmPFC) and decreased activation in the dorsal mPFC (dmPFC) and dorsal anterior cingulate cortex (dACC) during executive control and social cognition/emotion processing, respectively. In meta-regression analyses and subgroup meta-analyses, sex, cannabis use disorder (CUD) severity, and psychiatric comorbidity were correlated with brain activation differences between CU and TD youth in mPFC and insular cortical regions. Activation differences in the caudate, thalamus, insula, dmPFC/dACC, and precentral and postcentral gyri varied as a function of the length of abstinence. Conclusions: Using an SDM meta-analytic approach, this report identified differences in neuronal response between CU and TD youth during executive control, emotion processing, and reward processing in cortical and subcortical brain regions that varied as a function of sex, CUD severity, psychiatric comorbidity, and length of abstinence. Whether aberrant brain function in CU youth is attributable to common predispositional factors, cannabis-induced neuroadaptive changes, or both warrants further investigation.

An adaptive paradigm for detecting the individual duration of the preparatory period in the choice reaction time task

According to the sequential stage model, the selection and the execution of a motor response are two distinct independent processes. Here, we propose a new adaptive paradigm for identifying the individual duration of the response preparatory period based on the motor reaction time (RT) data. The results are compared using the paradigm with constant values of the preparatory period. Two groups of participants performed on either an easy (Group 1) or a hard (Group 2) response selection task with two types of stimuli based on the preparatory period parameters: (1) stimuli with a constant preparatory period duration of 0 or 1200 ms and (2) stimuli with adaptive preparatory period durations. Our analysis showed an increase in the duration of the response selection process as a function of increasing task complexity when using both paradigms with constant and adaptive values of the preparatory period duration. We conclude that the adaptive paradigm proposed in the current paper has several important advantages over the constant paradigm in terms of measuring the response accuracy while being equally efficiently in capturing other critical response parameters.

Investigating Temporal Memory Strength and Time-Based Impulse Control Using the DRL Task

Differential reinforcement of low rate (DRL) responding is a schedule-controlled behavior sometimes used in timing research, but also received critics of not providing a pure measure of timing due to the influence of the subject’s motivation or inhibitory control. Nevertheless, we argue that the DRL task provides a unique approach to study how timing and emotion interact with each other. Here, we review evidence showing that male rats prenatally treated with choline supplementation had difficulty in acquiring longer criterion times in the DRL task. This was possibly due to the stronger memory strength of their previously learned shorter criterion times. Female rats, in contrast, performed better than male rats in the same task, but those receiving prenatal choline supplementation were the best performers in this task with longer criterion times because they required less training. Like all female rats, male rats treated with prenatal choline supplementation made very few burst responses, suggesting that the treatment improved male rats’ emotional regulation when facing ‘frustrating’ outcomes. The differential impulse control plus different memory strength of the rats trained in the DRL task revealed the potential interaction of sex hormones and prenatal choline supplementation, a rare combination in a single animal study on timing and time perception. In summary, although the DRL task is certainly not the best timing task, it may be useful in assisting us in better understanding how time perception participates in emotional regulation, especially relevant when the emotion is triggered by a failure in timing.

Distinct brain structural abnormalities in attention-deficit/hyperactivity disorder and substance use disorders: A comparative meta-analysis

As two common mental disorders during the period of adolescence that extend to early adulthood, attention-deficit/hyperactivity disorder (ADHD) and substance use disorders (SUDs) have considerable diagnostic co-occurrence and shared neuropsychological impairments. Our study aimed to identify overlapping and distinct brain structural abnormalities associated with ADHD and SUDs among adolescents and young adults. A systematic literature search on voxel-based morphometry (VBM) studies of ADHD and SUDs was conducted in PubMed and Web of Science. Data were extracted and analyzed to identify brain abnormalities using Seed-based d-Mapping software. Data-driven functional decoding was conducted to identify the psychophysiological functioning associated with brain alterations. 13 and 14 VBM studies for ADHD (619 patients and 483 controls) and SUDs (516 patients and 413 controls), respectively, were included. Patterns of decreased gray matter volume (GMV) were found in the left precentral gyrus, bilateral superior frontal gyri, and left inferior frontal gyrus in the ADHD group compared to the control group. In contrast, individuals with SUDs, relative to controls, were characterized by increased GMV in the left putamen and insula. Comparative analysis indicated larger regional GMV in the right inferior parietal lobule and smaller volumes in the left putamen and left precentral gyrus in the ADHD group than in the SUDs group. Dissociable brain structural abnormalities in adolescents and young adults with ADHD and SUDs potentially implicate different pathogeneses and provide a reference for differential diagnosis and early detection for shared symptomology and comorbidity.

Differential expression of miR-1249-3p and miR-34b-5p between vulnerable and resilient phenotypes of cocaine addiction

Cocaine addiction is a complex brain disorder involving long-term alterations that lead to loss of control over drug seeking. The transition from recreational use to pathological consumption is different in each individual, depending on the interaction between environmental and genetic factors. Epigenetic mechanisms are ideal candidates to study psychiatric disorders triggered by these interactions, maintaining persistent malfunctions in specific brain regions. Here we aim to study brain-region-specific epigenetic signatures following exposure to cocaine in a mouse model of addiction to this drug. Extreme subpopulations of vulnerable and resilient phenotypes were selected to identify miRNA signatures for differential vulnerability to cocaine addiction. We used an operant model of intravenous cocaine self-administration to evaluate addictive-like behaviour in rodents based on the Diagnostic and Statistical Manual of Mental Disorders Fifth Edition criteria to diagnose substance use disorders. After cocaine self-administration, we performed miRNA profiling to compare two extreme subpopulations of mice classified as resilient and vulnerable to cocaine addiction. We found that mmu-miR-34b-5p was downregulated in the nucleus accumbens of vulnerable mice with high motivation for cocaine. On the other hand, mmu-miR-1249-3p was downregulated on vulnerable mice with high levels of motor disinhibition. The elucidation of the epigenetic profile related to vulnerability to cocaine addiction is expected to help find novel biomarkers that could facilitate the interventions to battle this devastating disorder.

Internet addiction among teenagers in a Chinese population: Prevalence, risk factors, and its relationship with obsessive-compulsive symptoms

BACKGROUND AND AIMS

Internet addiction (IA) among teenagers has been reported frequently in China, although research has seldom focused on vocational high school students. This study investigated the prevalence and risk factors among this special adolescent population. Moreover, we illustrate the complex relationship between obsessive-compulsive (OC) symptoms, insomnia, psychological states, and IA.

METHODS

A cross-sectional design was applied to collect information from three different vocational high schools in Hunan Province, China. Socio-demographic characteristics, OC symptoms, insomnia, depression, anxiety, and stress symptoms were compared between the IA and non-IA groups. Then, a structural equation model (SEM) was established to test our hypothesis regarding different paths from OC symptoms to IA.

RESULTS

IA prevalence was 13.4% among 7990 vocational high school students. Individuals with IA were more likely to be male and students with more severe depression, stress, anxiety, and insomnia symptoms (all p < 0.001). SEM verified that OC symptoms were related to IA both directly and indirectly, where the latter relationship was mediated through insomnia or mental disorders.

LIMITATIONS

This study cannot confirm the causal relationships among the variables and should be generalized cautiously to other groups.

CONCLUSIONS

More attention should be paid to Chinese vocational high school students, especially those with more severe OC symptoms, poor mental health, and insomnia. We should consider OC symptoms, insomnia, psychological suffering, and IA together when addressing related problems.

Molecular archaeology of human cognitive traits

The brains and minds of our human ancestors remain inaccessible for experimental exploration. Therefore, we reconstructed human cognitive evolution by projecting nonsynonymous/synonymous rate ratios (ω values) in mammalian phylogeny onto the anatomically modern human (AMH) brain. This atlas retraces human neurogenetic selection and allows imputation of ancestral evolution in task-related functional networks (FNs). Adaptive evolution (high ω values) is associated with excitatory neurons and synaptic function. It shifted from FNs for motor control in anthropoid ancestry (60-41 mya) to attention in ancient hominoids (26-19 mya) and hominids (19-7.4 mya). Selection in FNs for language emerged with an early hominin ancestor (7.4-1.7 mya) and was later accompanied by adaptive evolution in FNs for strategic thinking during recent (0.8 mya-present) speciation of AMHs. This pattern mirrors increasingly complex cognitive demands and suggests that co-selection for language alongside strategic thinking may have separated AMHs from their archaic Denisovan and Neanderthal relatives.

Subjective assessments of research domain criteria constructs in addiction and compulsive disorders: a scoping review protocol

INTRODUCTION

Obsessive-compulsive and related disorders (OCRDs) and disorders due to addictive behaviours (DABs) are prevalent conditions that share behavioural and neurobiological characteristics. The Research Domain Criteria lists a series of constructs whose dysfunctions may be present in both groups of disorders. The present study will describe the research protocol of a scoping review of the literature on self-report scales and questionnaires that tap dysfunctional constructs that underlie OCRDs and DABs.

METHODS AND ANALYSIS

This protocol outlines a scoping review on self-report tools and questionnaires that assess OCRDs and DABs-related constructs. The scoping review will select sources in MEDLINE, EMBASE, PsychINFO and Web of Science databases. Inclusion and exclusion criteria will be designed according to the Population, Concept, Context, Types of source framework. Two reviewers will screen independently titles, abstracts and full texts to determine the eligibility of articles. A methodological framework including six stages steps ((1) identifying a research question; (2) identifying relevant studies; (3) study selection; (4) charting the data; (5) collating, summarising and reporting the result) will be used, and the findings will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews checklist. Information extracted will be collated, and quantitative results will be presented using descriptive statistics such as percentages, tables, charts and flow diagrams as appropriate.

ETHICS AND DISSEMINATION

Ethical approval for conducting this scoping review is not required, as this study will involve secondary analysis of existing literature. The researchers will disseminate the study results via conference presentations and publication in a peer-reviewed journal.

SCOPING REVIEW PROTOCOL REGISTRATION

DOI 10.17605/OSF.IO/UJ7G5.

Sequential delay and probability discounting tasks in mice reveal anchoring effects partially attributable to decision noise

Delay discounting and probability discounting decision making tasks in rodent models have high translational potential. However, it is unclear whether the discounted value of the large reward option is the main contributor to variability in animals' choices in either task, which may limit translation to humans. Male and female mice underwent sessions of delay and probability discounting in sequence to assess how choice behavior adapts over experience with each task. To control for "anchoring" (persistent choices based on the initial delay or probability), mice experienced "Worsening" schedules where the large reward was offered under initially favorable conditions that became less favorable during testing, followed by "Improving" schedules where the large reward was offered under initially unfavorable conditions that improved over a session. During delay discounting, both male and female mice showed elimination of anchoring effects over training. In probability discounting, both sexes of mice continued to show some anchoring even after months of training. One possibility is that "noisy", exploratory choices could contribute to these persistent anchoring effects, rather than constant fluctuations in value discounting. We fit choice behavior in individual animals using models that included both a value-based discounting parameter and a decision noise parameter that captured variability in choices deviating from value maximization. Changes in anchoring behavior over time were tracked by changes in both the value and decision noise parameters in delay discounting, but by the decision noise parameter in probability discounting. Exploratory decision making was also reflected in choice response times that tracked the degree of conflict caused by both uncertainty and temporal cost, but was not linked with differences in locomotor activity reflecting chamber exploration. Thus, variable discounting behavior in mice can result from changes in exploration of the decision options rather than changes in reward valuation.

Distinct neural activation patterns of age in subcomponents of inhibitory control: A fMRI meta-analysis

Inhibitory control (IC) is a fundamental cognitive function showing age-related change across the healthy lifespan. Since different cognitive resources are needed in the two subcomponents of IC (cognitive inhibition and response inhibition), regions of the brain are differentially activated. In this study, we aimed to determine whether there is a distinct age-related activation pattern in these two subcomponents. A total of 278 fMRI articles were included in the current analysis. Multilevel kernel density analysis was used to provide data on brain activation under each subcomponent of IC. Contrast analyses were conducted to capture the distinct activated brain regions for the two subcomponents, whereas meta-regression analyses were performed to identify brain regions with distinct age-related activation patterns in the two subcomponents of IC. The results showed that the right inferior frontal gyrus and the bilateral insula were activated during the two IC subcomponents. Contrast analyses revealed stronger activation in the superior parietal lobule during cognitive inhibition, whereas stronger activation during response inhibition was observed primarily in the right inferior frontal gyrus, bilateral insula, and angular gyrus. Furthermore, regression analyses showed that activation of the left anterior cingulate cortex, left inferior frontal gyrus, bilateral insula, and left superior parietal lobule increased and decreased with age during cognitive inhibition and response inhibition, respectively. The results showed distinct activation patterns of aging for the two subcomponents of IC, which may be related to the differential cognitive resources recruited. These findings may help to enhance knowledge of age-related changes in the activation patterns of IC.