Sex differences in self-regulation: an evolutionary perspective

Relationship between bullying victimization and murderous behaviors and impulsivity's mediating role: Evidence from Chinese early adolescents

BACKGROUND

Evidence suggests a robust relationship between experiencing bullying victimization (BV) and engaging in murderous behaviors among adolescents. However, the potential mediating effect of impulsivity on the relationship between BV and murderous behaviors in early adolescents remains underexplored.

METHODS

A total of 5724 adolescents, with a mean age of 13.5 years, were enrolled from three middle schools in Anhui Province, China. Participants completed self-report questionnaires detailing their experiences with bullying, impulsiveness, and murderous behaviors. To assess the relationship between BV and murderous behaviors, multivariate logistic regression and Poisson regression analyses were conducted. Mediation analysis was performed using structural equation modeling.

RESULTS

After controlling for confounding factors, a positive association was found between experiencing BV and engaging in murderous behaviors (p < 0.05). Mediation analysis revealed a significant indirect effect of BV on the occurrence of murderous behaviors through impulsivity (indirect effect = 0.027, 95 % CI: 0.021, 0.033). BV appears to heighten levels of impulsivity, which in turn increases the likelihood of murderous behaviors. Additionally, sex-specific analysis indicated that impulsivity played a greater mediating role in the link between verbal and relational BV and murderous behaviors in females, while physical and cyber BV were more significant in males.

CONCLUSIONS

Our findings underscore the necessity of early targeted interventions for adolescents experiencing BV and exhibiting high levels of impulsivity to mitigate their risk of engaging in murderous behaviors.

The relationship between adolescent impulsivity, mental health, and internet addiction: a latent profile analysis

This study aimed to identify group variations in adolescent impulsivity and explore the connections between latent categories of impulsivity and psychological symptoms, social anxiety, and internet addiction. The research involved 2,378 participants from three middle schools in Guangdong Province, China. We assessed the impact of impulsivity levels (measured by BBIS) on depression (measured by KADS-11), anxiety (measured by SCARED), social anxiety (measured by SASC), and internet addiction (measured by YDQ). Latent profile analysis was employed to examine the diversity in adolescent impulsivity, establish latent classifications, and investigate the variances in psychological symptoms, social anxiety, and internet addiction. The middle school students were categorized into five latent groups based on their BBIS scores. Statistical analysis revealed five impulsivity categories, strongly linked to psychological symptoms and social anxiety but less strongly associated with internet addiction. The high impulsivity group (C5) exhibited higher scores in psychological symptoms and social anxiety compared to other groups, whereas the poor self-regulation group (C3) displayed greater psychological symptoms, social anxiety scores, and internet addiction than the impulsive behavior group (C4). Future investigations should investigate the underlying factors contributing to the observed differences among these groups.

Sex-specific impulsivity, but not other facets of executive function, predicts fat and sugar intake two-years later amongst adolescents with a healthy weight: Findings from the ABCD study

During adolescence, processes that control food intake (executive functions [EF]) undergo extensive refinement; underlying differences in EF may explain the inability to resist overeating unhealthy foods. Yet, overeating fat and sugar also causes changes to EF and cognition but disentangling these relationships has been difficult, as previous studies included youth with obesity. Here, amongst youth initially of a healthy weight, we evaluate whether 1) sex-specific underlying variation in EF/cognition at 9/10-years-old predict fat/sugar two-years later (Y2) and 2) if these relationships are moderated by body mass index (BMI), using linear mixed effects models (controlled for puberty, caregiver education; random effect: study site). Data were leveraged from Adolescent Brain Cognitive Development Study (n = 2987; 50.4% male; 15.4% Latino/a/x; 100% healthy weight at baseline; 12.4% overweight/obese by Y2, data release 4.0). EF and cognition (e.g., inhibition, cognition, motor, memory, impulsivity) were assessed with the NIH toolbox, Rey Auditory Verbal Learning Task, Little Man Task, the BIS/BAS, and UPPS-P. A saturated fat/added sugar (kcals) composite score was extracted from the validated Kids Food Block Screener. For males, greater baseline impulsivity (e.g., Positive Urgency, Lack of Planning and Perseverance) and reward (e.g., Fun seeking, Drive) was related to greater Y2 intake. For both sexes, greater baseline Negative Urgency and higher BMI was related to greater Y2 intake. No other relationships were observed. Our findings highlight a phenotype that may be more at risk for weight gain due to overconsumption of fat/sugar. Thus, prevention efforts may wish to focus on impulsive tendencies for these foods.

Psychometric properties of the Brazilian Portuguese version of the UPPS-P impulsive behavior scale for children and adolescents

OBJECTIVE

To translate and validate the version for children and adolescents of the UPPS-P scale into Brazilian Portuguese.

METHOD

After a five-step translation process, the final draft was submitted to a panel of 12 different specialties experts. Subsequently, the application of the scale was applied concomitantly with the "Swanson, Nolan, and Pelham Scale - Version IV" (SNAP-IV) and the "Child and Adolescent Behavior Inventory" (CABI) scale to analyze the correlation between them. Content Validity Index (CVI) and reliability were estimated by calculating internal consistency and analyzing its test-retest stability.

RESULTS

The items whose CVI was lower than 80% underwent a detailed analysis to verify the reason for the bad evaluation. Five items (3, 7, 11, 22 and 35) scored below 80% and were reassessed. There was high internal consistency in all parameters: Lack of premeditation (McDonald's omega = 0.806; Cronbach's alpha = 0.801), Negative Urgency (McDonald's omega = 0.838; Cronbach's alpha = 0.836), Sensation seeking (McDonald's omega = 0.826; Cronbach's alpha = 0.810), Lack of Perseverance (McDonald's omega = 0.800; Cronbach's alpha = 0.799) and Positive Urgency (McDonald's omega = 0.936; Cronbach's alpha = 0.934). A strong correlation was observed between UPPS-P features and impulsivity in behavioral assessments.

CONCLUSIONS

The Brazilian Portuguese version of the UPPS-P scale is a good instrument to assess impulsivity in children and adolescents.

Sexual Stimuli Cause Behavioral Disinhibition in Both Men and Women, but Even More So in Men

In our society men are considered more impulsive than women, especially in the violent and sexual domain. This correlation of sex and impulsivity might trace back to enhanced male impulsivity in general or a domain specific effect of emotions on impulsivity. The evidence for sex differences in the interaction of emotional or sexual stimuli and impulsivity has been relatively inconclusive so far. In this study, we investigated the effects of various emotional stimuli on responsivity in a Go/No-Go task. Participants had to respond quickly to a visual cue and withhold their response to another visual cue, while different emotional pictures were presented in the background, including sexual stimuli, non-sexual positive stimuli and negative stimuli. Both men (N = 37) and women (N = 38) made most commission errors in the sexual condition, indicating a disinhibiting effect in both genders. On top of this, men made even more commission errors than women, specifically in the sexual condition and not in other conditions. Men rated sexual stimuli as more positive, but did not differ from women in arousal ratings and pupil dilation. These findings may partly indicate increased impulsive behavior under sexual arousal in men, most likely driven by enhanced approach motivation due to more positive value but not higher arousal of sexual stimuli. The results are consistent with the theory of evolutionarily based concealment of sexual interest in women.

Emergence of Sex Differences in U.S. Adolescent Substance Use

Background: Adolescence is a common time for experimentation with substance use and the emergence of sex differences in substance use patterns. Although similar in early adolescence, male and female substance use patterns historically diverge by young adulthood, with males using more substances than females. We aim to add to current literature by utilizing a nationally representative sample, assessing a broad range of substances used, and focusing on a sentinel period during which sex differences emerge. We hypothesized that certain sex-specific substance use patterns emerge in adolescence. Methods: Data are from the 2019 Youth Risk Behavior Survey (n = 13,677), a nationally representative sample of high school students. Weighted logistic analyses of covariance adjusting for race/ethnicity evaluated males' and females' substance use (14 outcomes) by age category. Results: Among all adolescents, more males reported illicit substance use and cigarette smoking than females, whereas more females reported prescription opioid misuse, synthetic cannabis use, recent alcohol use, and binge drinking. Divergence between male and female use usually occurred at 18+ years. Odds of using most illicit substances were significantly greater among males than females at age 18+ years (aORs 1.7-4.47). Among 18+ year-olds, males and females did not differ in electronic vapor product use, alcohol use, binge drinking, cannabis use, synthetic cannabis use, cigarette smoking, or prescription opioid misuse. Conclusions: Sex differences in adolescent use of most but not all substances emerge by age 18+ years. Sex-specific patterns of adolescent substance use may inform specific prevention efforts and identify peak ages for intervention.

Long-interval intracortical inhibition in primary motor cortex related to working memory in middle-aged adults

Introduction

Excitability of the primary motor cortex measured with TMS has been associated with cognitive dysfunctions in patient populations. However, only a few studies have explored this relationship in healthy adults, and even fewer have considered the role of biological sex.

Methods

Ninety-seven healthy middle-aged adults (53 male) completed a TMS protocol and a neuropsychological assessment. Resting Motor Threshold (RMT) and Long-Interval Intracortical Inhibition (LICI) were assessed in the left motor cortex and related to attention, episodic memory, working memory, reasoning, and global cognition composite scores to evaluate the relationship between cortical excitability and cognitive functioning.

Results

In the whole sample, there was a significant association between LICI and cognition; specifically, higher motor inhibition was related to better working memory performance. When the sample was broken down by biological sex, LICI was only associated with working memory, reasoning, and global cognition in men. No associations were found between RMT and cognitive functions.

Conclusion

Greater intracortical inhibition, measured by LICI, could be a possible marker of working memory in healthy middle-aged adults, and biological sex plays a critical role in this association.

More than meets the eye: Examining physiological and behavioral regulation during delay of gratification task

Children continually encounter situations where they must regulate impulsive responses to achieve a goal, requiring both self‐control (SC) and delay of gratification. We examined concurrent behavioral SC strategies (fidgeting, vocalizations, anticipation) and physiological regulation (heart rate [HR], respiratory sinus arrhythmia [RSA]) in 126 children (M (SD) = 5.4 (0.29) years) during a standard delay of gratification task. Latent variable models derived latent SC classes and examined the moderating role of HR/RSA on SC and delay ability. Three classes of SC were identified: passive: low fidgeting and vocalizations, moderate anticipation; active: moderate fidgeting, low vocalizations, and high anticipation; and disruptive: moderate fidgeting, high vocalizations, and high anticipation. Children in the active class had the lowest odds of delaying full task time, compared to children in the passive (OR = 0.67, z = −5.25, p < .001) and disruptive classes (OR = 0.76, z = −2.03, p = .04). RSA changes during the task moderated the relationship between SC class and delay ability for children in the active class (aOR = 0.92, z = −3.1, p < .01). Within the group who struggled to delay gratification (active class), a subset exhibiting appropriate autonomic regulation was able to delay. The findings suggest probing congruency of observed behavioral and unobserved physiological regulation.

Characterization of a differential reinforcement of low rates of responding task in non-deprived male and female rats: Role of Sigma-1 receptors

Impulsive action can be defined as the inability to withhold a response and represents one of the dimensions of the broad construct impulsivity. Here, we characterized a modified differential reinforcement of low rates of responding (DRL) task developed in our laboratory, in which impulsive action is measured in ad libitum fed/watered subjects. Specifically, we first determined the effects of both sex and estrous cycle on impulsive action by systematically comparing male and estrous-synchronized female subjects. In addition, we evaluated the convergent validity of this modified DRL task by testing the effects of the D2R/5HT2AR antagonist, aripiprazole, and the noncompetitive NMDAR antagonist, MK-801. Finally, we tested the effects of the selective antagonist BD-1063 and agonist PRE-084 of Sigma-1 receptor (Sig-1R) on impulsive action using this modified DRL task. We found that female rats showed and increased inability to withhold a response when compared to males, and this effect was driven by the metestrus/diestrus phase of the estrous cycle. In addition, aripiprazole and MK-801 fully retained their capability to reduce and increase impulsive action, respectively. Finally, the selective Sig-1R antagonist, BD-1063 dose-dependently reduced the inability to withhold a response in both sexes, though more potently in female rats. In summary, we show that impulsive action, as measured in a modified DRL task which minimizes energy-homeostatic influences, is a function of both sex and estrous cycle. Furthermore, we validate the convergent validity of the task and provide evidence that Sig-1R antagonism may represent a novel pharmacological strategy to reduce impulsive action.

Effect of Sex and Reproductive Status on Inhibitory Control and Social Cognition in the Domestic Dog (Canis familiaris)

Simple Summary

Various behavioral differences exist between male and female dogs, but very little research has focused on how sex influences cognition. Even fewer studies have taken sex hormones into account. Our aim was to investigate whether dogs’ sex and neutering status can influence two important cognitive traits: inhibitory control and social cognition. Inhibitory control was assessed using the cylinder test. In this task, the dog is required to inhibit reaching for a treat directly through a transparent barrier, and instead go around the barrier to access the treat. Social cognition was assessed using the unsolvable task, during which a food reward is visible but impossible to access. Dogs have three opportunities for action in this situation: (a) persisting with the problem independently, (b) seeking attention from a human, or (c) abandoning the task. Males were more impulsive and independent compared to females, whereas females had greater inhibitory control and were more likely to gaze at a human during a problem-solving situation. Since neutering status did not affect the results, it seems likely that these sex differences arose during early development and were not affected by levels of circulating sex hormones to a great extent.

Abstract

Sex differences in a variety of cognitive traits have long been reported in various species, including dogs. However, only a few canine studies have taken the possible effect of reproductive hormones into account. The aim of this study was to investigate the effects of sex and reproductive status of pet dogs (N = 1032) on two cognitive traits: inhibitory control and social cognition. Inhibitory control was assessed using the cylinder test, and the dogs’ tendency to initiate social contact with a human during a problem-solving situation was assessed using the unsolvable task. Female dogs had a significantly higher success rate in the cylinder test compared to males, and they spent significantly more time in human-directed behavior during the unsolvable task. In contrast, males spent significantly more time in independent behavior during the unsolvable task. Reproductive status had no significant effect on the results of the cylinder test or the unsolvable task. Our results showed that female dogs asked for more help/used a more cooperative strategy during a problem-solving situation and had greater inhibitory control compared to males. According to our results, it seems likely that these sex differences were not influenced to a large extent by reproductive hormones.

Age, Sex, and Inhibitory Control: Identifying A Specific Impairment in Memorial, But Not Perceptual Inhibition in Older Women

Objectives

Declines in the ability to inhibit information, and the consequences to memory of unsuccessful inhibition, have been frequently reported to increase with age. However, few studies have investigated whether sex moderates such effects. Here, we examined whether inhibitory ability may vary as a function of age and sex, and the interaction between these two factors.

Method

202 older (mean age = 69.40 years) and younger (mean age =30.59 years) participants who had equivalent educational attainment and self-reported health completed 2 tasks that varied only in the time point at which inhibition should occur: either prior to, or after, encoding.

Results

While we did not find evidence for age or sex differences in inhibitory processes when information needed to be inhibited prior to encoding, when encoded information being actively held in working memory needed to be suppressed, we found that older women were particularly impaired relative to both younger women and men of either age group.

Discussion

These results provide further support for the presence of memorial inhibitory deficits in older age, but add nuance by implicating biological sex as an important mediator in this relationship, with it more difficult for older women to inhibit what was once relevant in memory.

Intergenerational transmission of appetite self-regulation

Parents and other primary caregivers affect the development of children's self-regulation in myriad ways, including via the parent's own self-regulation abilities. Ample evidence supports the association between mother and child self-regulation, yet this has never been experimentally assessed with regard to appetite self-regulation, the self-regulation of food intake. This study sought to explicitly test the associations between mother and child self-regulation across 3 domains: (1) appetite, (2) attentional control, and (3) inhibitory control. A community sample of 88 mother-preschooler dyads (ages 3-5) participated in this cross-sectional, experimental study. Results demonstrated that maternal self-regulation was significantly positively associated with child self-regulation in the appetite domain, b = 0.52, t(63.54) = 2.39, p = .020, but not for attentional or inhibitory control. These results add to the literature on parental influences on self-regulation development in early childhood and suggest that patterns of mother-child associations may vary across domains of self-regulation.

Associations among response inhibition, motivational beliefs, and task persistence in early elementary school

Task persistence is an important learning-related behavior associated with academic success. Although persistence has been related to motivational beliefs and cognitive skills, these constructs are typically studied independently, limiting our understanding of relations among them. The current investigation was designed to understand how these concepts are related in early elementary school, a developmental period characterized by high motivational beliefs, growth in cognitive control, and the transition to school. Interest, perceived competence, and response inhibition were evaluated as predictors of children's (N = 73, M_age = 6.91 years) likelihood to demonstrate high persistence on a challenging puzzle task. Results provided evidence that motivational constructs are not sufficient for understanding differences in persistent behavior during this developmental period. Specifically, relations between interest and perceived competence and task persistence were present only for children with moderate to high response inhibition skills. Moreover, gender differences in task persistence emerged, indicating that although interest and perceived competence motivated all students to exhibit persistence, girls were still more likely to demonstrate task persistence than boys. Overall, findings suggest that task persistence in elementary school is a complex behavior that requires both cognitive control skills to support engagement and the motivation to continue engaging as task difficulty increases.

Dimensional bias and adaptive adjustments in inhibitory control of monkeys

Humans and macaque monkeys, performing a Wisconsin Card Sorting Test (WCST), show a significant behavioral bias to a particular sensory dimension (e.g. color or shape); however, lesions in prefrontal cortical regions do not abolish the dimensional biases in monkeys and, therefore, it has been proposed that these biases emerge in earlier stages of visual information processing. It remains unclear whether such dimensional biases are unique to the WCST, in which attention-shifting between dimensions are required, or affect other aspects of executive functions such as 'response inhibition' and 'error-induced behavioral adjustments'. To address this question, we trained six monkeys (Macaca mulatta) to perform a stop-signal task in which they had to inhibit their response when an instruction for inhibition was given by changing the color or shape of a visual stimulus. Stop Signal Reaction Time (SSRT) is an index of inhibitory processes. In all monkeys, SSRT was significantly shorter, and the probability of a successful inhibition was significantly higher, when a change in the shape dimension acted as the stop-cue. Humans show a response slowing following a failure in response inhibition and also adapt a proactive slowing after facing demands for response inhibition. We found such adaptive behavioral adjustments, with the same pattern, in monkeys' behavior; however, the dimensional bias did not modulate them. Our findings, showing dimensional bias in monkey, with the same pattern, in two different executive control tasks support the hypothesis that the bias to shape dimension emerges in early stages of visual information processing.

Relations of Maternal Depression and Parenting Self-Efficacy to the Self-Regulation of Infants in Low-Income Homes

There is increasing recognition that young children's self-regulation provides a foundation for overall wellness later in life. Yet, infants reared in poverty may exhibit less-developed self-regulation compared to their more advantaged peers. Factors associated with poverty that may influence early self-regulation include maternal depression and parenting self-efficacy. However, few researchers have examined how both parenting self-efficacy and maternal depression may affect young children's self-regulation. The purpose of this study was to investigate the associations among maternal depression, parenting self-efficacy, and infant self-regulation for a racially diverse sample of 142 mother-infant dyads living in low-income households in the United States. Maternal depressive symptomatology was determined with the Edinburgh Postnatal Depressive Scale. Parenting self-efficacy was determined with a self-report measure, reflecting caregivers' mindset or feelings reflecting competency as a parent of an infant. Infant self-regulation was measured by parental report of the Infant Behavior Questionnaire Short Form Effortful Control subscale. While maternal depressive symptomatology and self-efficacy were directly and significantly correlated with infant self-regulation, results of a mediation model suggested that parenting self-efficacy mediated the relationship between maternal depressive symptomatology and infant self-regulation. Lower maternal depressive symptomatology predicted better parenting self-efficacy, in turn predicting better infant self-regulation. This study increases our understanding of how early factors shape the self-regulation of infants reared in low-income homes - highlighting the potential role of targeting parenting self-efficacy for parenting interventions for mothers experiencing depressive symptoms.

Cross-lagged associations between behaviour problems and obesity in head start preschoolers

BACKGROUND

Behaviour problems and obesity are related but research findings have been inconclusive regarding the direction of effects.

OBJECTIVES

This study examined the cross-lagged associations between behaviour problems, body mass index (BMI) and obesity in preschoolers, and whether sex modified these associations.

METHODS

Repeated measures of teacher-reported externalizing (EXT) and internalizing behaviour problems (clinically significant T scores were >90th percentile), BMI z-scores (BMI-Z) and obesity status (BMI ≥95th for age and sex) were assessed in the fall (T1) and spring (T2) of the school year in Head Start preschoolers (N = 423). Associations were examined with cross-lagged modelling.

RESULTS

Prospective paths from T1 clinically significant EXT to both T2 BMI-Z (β = .05) and obesity (β = .18) were significant. There was no evidence that T1 BMI-Z or obesity preceded T2 behaviour problems. However, sex-specific models indicated that T1 BMI-Z was prospectively associated with higher T2 EXT for boys (β = .13), but not girls. T1 EXT was predictive of subsequent BMI-Z (β = .09) and obesity (β = .33) at T2 for girls only.

CONCLUSION

Findings suggest that behaviour problems, particularly externalizing behaviours, are prospectively related to childhood obesity, and early prevention methods should reflect sex-specific modifications.

Neural Responses to Reward in a Gambling Task: Sex Differences and Individual Variation in Reward-Driven Impulsivity

Previous work suggests sex differences in reward sensitivity. However, it remains unclear how men and women differ in the neural processes of reward-driven impulsivity. With a data set of 968 subjects (502 women) curated from the Human Connectome Project, we investigated sex differences in regional activations to reward and to punishment in a gambling task. Individual variations in reward-driven impulsivity were quantified by the difference in reaction time between reward and punishment blocks in the gambling task, as well as by a behavioral measure of delay discounting. At a corrected threshold, men and women exhibited significant differences in regional activations to reward and to punishment. Longer reaction times during reward versus punishment blocks, indicative of more cautious responding, were associated with left-hemispheric lateral prefrontal cortical activation to reward in men but not women. Steeper discounting was associated with higher activation to reward in the right-hemispheric dorsal anterior cingulate cortex and angular gyrus in women but not men. These sex differences were confirmed in slope tests. Together, the results highlight the sex-specific neural processes of reward-driven impulsivity with left-hemispheric prefrontal cortex supporting impulse control in men and right-hemispheric saliency circuit playing a more important role in diminished impulse control in women.

Self-Regulation is Bi-Directionally Associated with Cognitive Development in Children with Autism

Children with autism are at high risk for self-regulation difficulties because of language delays and emotion-regulation difficulties. In typically-developing children, language development helps promote self-regulation, and in turn, cognitive development. Little research has examined the association between self-regulation and cognitive-skill development in children with autism. Children with autism (5-8 years), who were minimally-verbal (n=38) or typically-verbal (n=46) participated in a structured cognitive assessment and were observed for self-regulation difficulties during the cognitive assessment at the beginning and end of an academic year. Results showed that children with autism who were minimally- compared to typically-verbal had more self-regulation difficulties. Increase in self-regulation difficulties predicted less cognitive-skill gains, regardless of verbal ability, and cognitive skill gains also predicted changes in self-regulation difficulties. Interventions targeting self-regulation may be appropriate for all children with autism and should be adapted for minimally-verbal children.

Sex Differences and Effects of Predictive Cues on Delayed Punishment Discounting

The majority of the research studying punishment has focused on an aversive stimulus delivered immediately after an action. However, in real-world decision-making, negative consequences often occur long after a decision has been made. This can engender myopic decisions that fail to appropriately respond to consequences. Whereas discounting of delayed rewards has been well studied in both human and animal models, systematic discounting of delayed consequences remains largely unexplored. To address this gap in the literature, we developed the delayed punishment decision-making task. Rats chose between a small, single-pellet reinforcer and a large, three-pellet reinforcer accompanied by a mild foot shock. The shock was preceded by a delay, which systematically increased throughout the session (0, 4, 8, 12, 16 s). On average, rats discounted the negative value of delayed punishment, as indicated by increased choice of the large, punished reward as the delay preceding the shock lengthened. Female rats discounted delayed punishment less than males, and this behavior was not influenced by estrous cycling. The addition of a cue light significantly decreased the undervaluation of delayed consequences for both sexes. Finally, there was no correlation between the discounting of delayed punishments and a traditional reward delay discounting task for either sex. These data indicate that the ability of punishment to regulate decision-making is attenuated when punishment occurs later in time. This task provides an avenue for exploration of the neural circuitry underlying the devaluation of delayed punishment and may assist in developing treatments for substance use disorders.

Sex Hormones and Gender Role Relate to Gray Matter Volumes in Sexually Dimorphic Brain Areas

The present study investigates the relationship of circulating sex hormone levels and gender role to gray matter volumes in sexually dimorphic brain areas and explores, whether these relationships are modulated by biological sex (as assigned at birth based on sexual anatomy) or oral contraceptive (OC) use. It was hypothesized that testosterone and masculinity relate positively to gray matter volumes in areas that are typically larger in men, like the hippocampus or cerebellum, while estradiol/progesterone and femininity relate positively to gray matter volumes in the frontal cortex. To that end, high resolution structural MRI scans, sex hormone levels and gender role self-assessments were obtained in a large sample 89 men, 89 naturally cycling (NC) women, and 60 OC users. Men showed larger regional gray matter volumes than women in the cerebellum and bilateral clusters spanning the putamen and parts of the hippocampi/parahippocampi and fusiform gyri. In accordance with our hypotheses, a significant positive association of testosterone to hippocampal volumes was observed in women irrespective of OC use. Participant's self-reported femininity was significantly positively associated with gray matter volumes in the left middle frontal gyrus (MFG) in men. In addition several differences between OC-users and NC women were identified.

Brain structure and trait impulsivity: A comparative VBM study contrasting neural correlates of traditional and alternative concepts in healthy subjects

Impulsivity as a trait modulates a range of cognitive functions, e.g. planning, decision-making, or response inhibition. Recent behavioural and psychometric findings challenge both the neurobiological models as well as the conceptualisation of psychometric measures of impulsivity. In the present study, we aimed to test the association of brain structure with the Barratt Impulsiveness Scale (BIS-11), a commonly applied self-rating instrument for impulsivity, using both the classical three-factor-model for impulsive behaviour (motor (IM), attentional (IA) and non-planning impulsivity (INP)), as well as the recently proposed alternative model contrasting inability to wait for reward (IWR) as an index of impulsive choice and rapid response style (RRS) as an index of impulsive action. We analysed brain structural data in a community sample of 85 healthy individuals, who completed the BIS-11, using voxel-based morphometry (CAT12: Computational Anatomy Toolbox 12). Regional volumes were correlated with the three traditional BIS-11 subscales, as well as IWR and RRS. BIS-11 total score was positively correlated with right inferior parietal, postcentral, and supramarginal grey matter (p < 0.05, FWE cluster-level corrected). Attentional impulsivity (IA) was also positively correlated with right inferior and superior parietal and supramarginal gyri. Comparison of the other scales did show some divergence, but most correlations did not survive correction for multiple comparisons. Our findings suggest that difference facets of trait impulsivity might be related to different brain areas, and might thus dissociate along distinct but overlapping neural networks. In contrast to lesion or patient studies, these analyses delineate physiological variance, and can thus help to conceptualise network models in the absence of pathology.

Electrophysiological Properties of Medium Spiny Neuron Subtypes in the Caudate-Putamen of Prepubertal Male and Female Drd1a-tdTomato Line 6 BAC Transgenic Mice

The caudate-putamen is a striatal brain region essential for sensorimotor behaviors, habit learning, and other cognitive and premotor functions. The output and predominant neuron of the caudate-putamen is the medium spiny neuron (MSN). MSNs present discrete cellular subtypes that show differences in neurochemistry, dopamine receptor expression, efferent targets, gene expression, functional roles, and most importantly for this study, electrophysiological properties. MSN subtypes include the striatonigral and the striatopallidal groups. Most studies identify the striatopallidal MSN subtype as being more excitable than the striatonigral MSN subtype. However, there is some divergence between studies regarding the exact differences in electrophysiological properties. Furthermore, MSN subtype electrophysiological properties have not been reported disaggregated by biological sex. We addressed these questions using prepubertal male and female Drd1a-tdTomato line 6 BAC transgenic mice, an important transgenic line that has not yet received extensive electrophysiological analysis. We made acute caudate-putamen brain slices and assessed a robust battery of 16 relevant electrophysiological properties using whole-cell patch-clamp recording, including intrinsic membrane, action potential, and miniature EPSC (mEPSC) properties. We found that: (1) MSN subtypes exhibited multiple differential electrophysiological properties in both sexes, including rheobase, action potential threshold and width, input resistance in both the linear and rectified ranges, and mEPSC amplitude; (2) select electrophysiological properties showed interactions between MSN subtype and sex. These findings provide a comprehensive evaluation of mouse caudate-putamen MSN subtype electrophysiological properties across females and males, both confirming and extending previous studies.

Putting out the blaze: The neural mechanisms underlying sexual inhibition

The successful inhibition of sexual thoughts, desires, and behaviors represents an essential ability for adequate functioning in our daily life. Evidence derived from lesion studies indicates a link between sexual inhibition and the general ability for behavioral and cognitive control. This is further supported by the high comorbidity of sexual compulsivity with other inhibition-related disorders. Here, we aimed at investigating whether sexual and general inhibition recruit overlapping or distinct neural correlates in the brain. Furthermore, we investigated the specificity of two different kinds of sexual inhibition: inhibition of sexually driven motor responses and inhibition of sexual incoming information. To this end, 22 healthy participants underwent functional Magnetic Resonance Imaging (fMRI) while performing a task requiring general response inhibition (Go/No-go), as well as cognitive and motivational sexual inhibition (Negative Affective Priming and Approach-Avoidance task). Our within-subject within-session design enabled the direct statistical comparison between general and sexual inhibitory mechanisms. The general inhibition task recruited mainly prefrontal and insular regions, replicating previous findings. In contrast, the two types of sexual inhibition activated both common and distinct neural networks. Whereas cognitive sexual inhibition engaged the inferior frontal gyrus, the orbitofrontal cortex and the fusiform gyrus, motivational sexual inhibition was characterized by a hypoactivation in the anterolateral prefrontal cortex. Both types of sexual inhibition recruited the inferior frontal gyrus and the inferotemporal cortex. However, the activity of the inferior frontal gyrus did not correlate with behavioral inhibitory scores. These results support the hypothesis of inhibitory processing being an emergent property of a functional network.

Marriage as a training ground: Examining change in self-control and forgiveness over the first 4 years of marriage

Do partners' levels of self-control and forgiveness change over the course of marriage? Based on the idea that marriage may function as a training ground for these vital relationship abilities, we hypothesized that people increase their levels of self-control and forgiveness over time and that these developments take place simultaneously. We tested these predictions among 199 newlywed couples in the first 4 years of marriage, using a dyadic latent growth curves analysis. Confirming our hypotheses, results showed significant increases in self-control and forgiveness as well as a positive concurrent correlation between these variables. However, the developments of self-control and forgiveness were unrelated. So, while people become more self-controlled and forgiving over the course of a marriage, these developments do not coincide.

The role of gender in association between inhibition capacities and risky decision making

BACKGROUND

Research on the association between decision making and inhibition abilities has exhibited fundamental controversies. Some authors claim that inhibition abilities are an integral part of the decision-making process, whereas others suggest that the decision-making process does not operate in close association with inhibition abilities. Can gender explain variations in risky decisions via inhibition influences?

PURPOSE

The purpose of the present study was to explore the associations between response inhibition, reflection inhibition, interference inhibition, and decision-making processes in men and women.

METHODS

To this end, 46 women and 46 men were assessed by the Go/NoGo task, a measure of response inhibition, by the Matching Familiar Figure Test, a measure of reflection inhibition; and by the Stroop task, a measure of interference inhibition.

RESULTS

No differences were detected in these measures between groups. The net score of the performance on the last section of the Iowa Gambling Task choices did not correlate with the inhibition measures in the two groups. We did not discover any significant main effects of gender on the association between these measures.

CONCLUSION

These findings do not support the hypothesis that risky decisions are due to impaired inhibitory control. Further studies are needed to identify the cognitive mechanisms involved in the tendency to make risky decisions.

Correlations Between Personality and Brain Structure: A Crucial Role of Gender

Previous studies have shown that males and females differ in personality and gender differences have also been reported in brain structure. However, effects of gender on this "personality-brain" relationship are yet unknown. We therefore investigated if the neural correlates of personality differ between males and females. Whole brain voxel-based morphometry was used to investigate the influence of gender on associations between NEO FFI personality traits and gray matter volume (GMV) in a matched sample of 182 males and 182 females. In order to assess associations independent of and dependent on gender, personality-GMV relationships were tested across the entire sample and separately for males and females. There were no significant correlations between any personality scale and GMV in the analyses across the entire sample. In contrast, significant associations with GMV were detected for neuroticism, extraversion, and conscientiousness only in males. Interestingly, GMV in left precuneus/parieto-occipital sulcus correlated with all 3 traits. Thus, our results indicate that brain structure-personality relationships are highly dependent on gender, which might be attributable to hormonal interplays or differences in brain organization between males and females. Our results thus provide possible neural substrates of personality-behavior relationships and underline the important role of gender in these associations.

Disruption in time projection and non-adherence to long-term therapies

OBJECTIVE

Patients' non-adherence to medical prescriptions is a crucial issue in contemporary medicine because it can jeopardize care efficacy. Non-adherence is especially frequent in patients with chronic diseases. In this article, we propose that a particular condition, which we call disruption in time projection, is a cause of non-adherence to medication therapies in chronic diseases.

METHODS

A questionnaire was administered to 120 hospitalized people with type 2 diabetes addressing three psychological constructs defining time projection: patience/impatience in a fictive monetary scenario (preferring to receive €1,500 in 1 year or €500 today), magnitude of temporal horizon (greater or lesser ability to imagine future events) and perception of the degree of physical similarity of current self to self at 1 year, 5 years and 10 years from the present. In addition, the questionnaire evaluated adherence to medication, social deprivation and depression.

RESULTS

In the multivariate analyses, two factors were associated with adherence to medication: patience (P<0.001) and long temporal horizon (P=0.006). Two factors were associated with HbA1c ≥8% (64 mmol/mol): non-adherence to medication (P=0.003) and short temporal horizon (P=0.011). Three factors were associated with long temporal horizon: adherence to medication (P<0.001), patience (P<0.001) and the existence of grandchildren (P=0.002). Social deprivation (P<0.001), non-adherence (P<0.001), female gender (P=0.002) and short temporal horizon (P=0.050) were associated with impatience. Finally, an association of adherence to expected similarity in the future to current self, impatience, short temporal horizon, social deprivation and depression was also shown in a multiple correspondence analysis.

CONCLUSION

What we termed a disruption in time projection may be a unique determinant for non-adherence to long-term therapy and, therefore, may influence the outcome of chronic diseases. We hypothesize that this is involved in both intentional and unintentional non-adherence and that it represents the loss of a protective mechanism. If this novel concept is to be confirmed in other settings and generalized to other chronic diseases, the recognition of its role in disease prognosis may help orient the teaching and practice of medicine.

Serotonergic modulation of orbitofrontal activity and its relevance for decision making and impulsivity

BACKGROUND

The orbitofrontal cortex seems to play a crucial role in reward-guided learning and decision making, especially for impulsive choice procedures including delayed reward discounting. The central serotonergic system is closely involved in the regulation of impulsivity, but how the serotonergic firing rate and release, best investigated by the loudness dependence of auditory evoked potentials (LDAEP), interact with orbitofrontal activity is still unknown.

METHODS

Twenty healthy volunteers (11 males, 9 females, 31.3 ± 10.6 years old) were studied in a 3T MRI scanner (Philips, Hamburg, Germany) during a delay discounting task, after their LDAEP was recorded using a 32 electrodes EEG machine (Brain Products, Munich, Germany).

RESULTS

Significant positive correlations were only found between the LDAEP and the medial orbitofrontal part of the superior frontal gyrus (SFG/MO) [Δ immediate reward - delayed reward] for the right (r = 0.519; P = 0.019) and left side (r = 0.478; P = 0.033). This relationship was stronger for females compared with males. Orbitofrontal activity was also related to the Barratt Impulsivity Scale.

CONCLUSIONS

This study revealed that low serotonergic activity as measured by a strong LDAEP was related to a high fMRI signal intensity of SFG/MO during immediate reward behavior which is related to impulsivity. Since this relationship was only found for the infralimbic medial and not for the middle or lateral part of the orbitofrontal cortex, an exclusive projection tract of the serotonergic system to this cortical region can be assumed to regulate impulsive reward-orientated decision making. Hum Brain Mapp 38:1507-1517, 2017. © 2016 Wiley Periodicals, Inc.

Sex dependency of inhibitory control functions

BACKGROUND

Inhibition of irrelevant responses is an important aspect of cognitive control of a goal-directed behavior. Females and males show different levels of susceptibility to neuropsychological disorders such as impulsive behavior and addiction, which might be related to differences in inhibitory brain functions.

METHODS

We examined the effects of 'practice to inhibit', as a model of rehabilitation approach, and 'music', as a salient contextual factor in influencing cognition, on the ability of females and males to perform a stop-signal task that required inhibition of initiated or planned responses. In go trials, the participants had to rapidly respond to a directional go cue within a limited time window. In stop trials, which were presented less frequently, a stop signal appeared immediately after the go-direction cue and the participants had to stop their responses.

RESULTS

We found a significant difference between females and males in benefiting from practice in the stop-signal task: the percentage of correct responses in the go trials increased, and the ability to inhibit responses significantly improved, after practice in females. While listening to music, females became faster but males became slower in responding to the go trials. Both females and males became slower in performing the go trials following an error in the stop trials; however, music significantly affected this post-error slowing depending on the sex. Listening to music decreased post-error slowing in females but had an opposite effect in males.

CONCLUSIONC

Here, we show a significant difference in executive control functions and their modulation by contextual factors between females and males that might have implications for the differences in their propensity for particular neuropsychological disorders and related rehabilitation approaches.

Genetic sex and the volumes of the caudate-putamen, nucleus accumbens core and shell: original data and a review

Sex differences are widespread across vertebrate nervous systems. Such differences are sometimes reflected in the neural substrate via neuroanatomical differences in brain region volume. One brain region that displays sex differences in its associated functions and pathologies is the striatum, including the caudate-putamen (dorsal striatum), nucleus accumbens core and shell (ventral striatum). The extent to which these differences can be attributed to alterations in volume is unclear. We thus tested whether the volumes of the caudate-putamen, nucleus accumbens core, and nucleus accumbens shell differed by region, sex, and hemisphere in adult Sprague-Dawley rats. As a positive control for detecting sex differences in brain region volume, we measured the sexually dimorphic nucleus of the medial preoptic area (SDN-POA). As expected, SDN-POA volume was larger in males than in females. No sex differences were detected in the volumes of the caudate-putamen, nucleus accumbens core or shell. Nucleus accumbens core volume was larger in the right than left hemisphere across males and females. These findings complement previous reports of lateralized nucleus accumbens volume in humans, and suggest that this may possibly be driven via hemispheric differences in nucleus accumbens core volume. In contrast, striatal sex differences seem to be mediated by factors other than striatal region volume. This conclusion is presented within the context of a detailed review of studies addressing sex differences and similarities in striatal neuroanatomy.

Neonatal handling causes impulsive behavior and decreased pharmacological response to methylphenidate in male adult wistar rats

Neonatal handling has an impact on adult behavior of experimental animals and is associated with rapid and increased palatable food ingestion, impaired behavioral flexibility, and fearless behavior to novel environments. These symptoms are characteristic features of impulsive trait, being controlled by the medial prefrontal cortex (mPFC). Impulsive behavior is a key component of many psychiatric disorders such as attention deficit hyperactivity disorder (ADHD), manic behavior, and schizophrenia. Others have reported a methylphenidate (MPH)-induced enhancement of mPFC functioning and improvements in behavioral core symptoms of ADHD patients. The aims of the present study were: (i) to find in vivo evidence for an association between neonatal handling and the development of impulsive behavior in adult Wistar rats and (ii) to test whether neonatal handling could have an impact on monoamine levels in the mPFC and the pharmacological response to MPH in vivo. Therefore, experimental animals (litters) were classified as: "non-handled" and "handled" (10[Formula: see text]min/day, postnatal days 1-10). After puberty, they were exposed to either a larger and delayed or smaller and immediate reward (tolerance to delay of reward task). Acute MPH (3[Formula: see text]mg/Kg. i.p.) was used to suppress and/or regulate impulsive behavior. Our results show that only neonatally handled male adult Wistar rats exhibit impulsive behavior with no significant differences in monoamine levels in the medial prefrontal cortex, together with a decreased response to MPH. On this basis, we postulate that early life interventions may have long-term effects on inhibitory control mechanisms and affect the later response to pharmacological agents during adulthood.

Sex-dependent effects on tasks assessing reinforcement learning and interference inhibition

Increasing evidence suggests that the prefrontal cortex (PFC) is influenced by sex steroids and that some cognitive functions dependent on the PFC may be sexually differentiated in humans. Past work has identified a male advantage on certain complex reinforcement learning tasks, but it is unclear which latent task components are important to elicit the sex difference. The objective of the current study was to investigate whether there are sex differences on measures of response inhibition and valenced feedback processing, elements that are shared by previously studied reinforcement learning tasks. Healthy young adults (90 males, 86 females) matched in general intelligence completed the Probabilistic Selection Task (PST), a Simon task, and the Stop-Signal task. On the PST, females were more accurate than males in learning from positive (but not negative) feedback. On the Simon task, males were faster than females, especially in the face of incongruent stimuli. No sex difference was observed in Stop-Signal reaction time. The current findings provide preliminary support for a sex difference in the processing of valenced feedback and in interference inhibition.

Emergence of sex differences in the development of substance use and abuse during adolescence

Substance use and abuse begin during adolescence. Male and female adolescent humans initiate use at comparable rates, but males increase use faster. In adulthood, more men than women use and abuse addictive drugs. However, some women progress more rapidly from initiation of use to entry into treatment. In animal models, adolescent males and females consume addictive drugs similarly. However, reproductively mature females acquire self-administration faster, and in some models, escalate use more. Sex/gender differences exist in neurobiologic factors mediating both reinforcement (dopamine, opioids) and aversiveness (CRF, dynorphin), as well as intrinsic factors (personality, psychiatric co-morbidities) and extrinsic factors (history of abuse, environment especially peers and family) which influence the progression from initial use to abuse. Many of these important differences emerge during adolescence, and are moderated by sexual differentiation of the brain. Estradiol effects which enhance both dopaminergic and CRF-mediated processes contribute to the female vulnerability to substance use and abuse. Testosterone enhances impulsivity and sensation seeking in both males and females. Several protective factors in females also influence initiation and progression of substance use including hormonal changes of pregnancy as well as greater capacity for self-regulation and lower peak levels of impulsivity/sensation seeking. Same sex peers represent a risk factor more for males than females during adolescence, while romantic partners increase risk for women during this developmental epoch. In summary, biologic factors, psychiatric co-morbidities as well as personality and environment present sex/gender-specific risks as adolescents begin to initiate substance use.

Intrinsic excitability varies by sex in prepubertal striatal medium spiny neurons

Sex differences in neuron electrophysiological properties were traditionally associated with brain regions directly involved in reproduction in adult, postpubertal animals. There is growing acknowledgement that sex differences can exist in other developmental periods and brain regions as well. This includes the dorsal striatum (caudate/putamen), which shows robust sex differences in gene expression, neuromodulator action (including dopamine and 17β-estradiol), and relevant sensorimotor behaviors and pathologies such as the responsiveness to drugs of abuse. Here we examine whether these sex differences extend to striatal neuron electrophysiology. We test the hypothesis that passive and active medium spiny neuron (MSN) electrophysiological properties in prepubertal rat dorsal striatum differ by sex. We made whole cell recordings from male and females MSNs from acute brain slices. The slope of the evoked firing rate to current injection curve was increased in MSNs recorded from females compared with males. The initial action potential firing rate was increased in MSNs recorded from females compared with males. Action potential after-hyperpolarization peak was decreased, and threshold was hyperpolarized in MSNs recorded from females compared with males. No sex differences in passive electrophysiological properties or miniature excitatory synaptic currents were detected. These findings indicate that MSN excitability is increased in prepubertal females compared with males, providing a new mechanism that potentially contributes to generating sex differences in striatal-mediated processes. Broadly, these findings demonstrate that sex differences in neuron electrophysiological properties can exist prepuberty in brain regions not directly related to reproduction.