No Sex Difference Found: Cues of Sexual Stimuli Activate the Reward System in both Sexes

Appetitive conditioning with pornographic stimuli elicits stronger activation in reward regions than monetary and gaming-related stimuli

Appetitive conditioning plays an important role in the development and maintenance of pornography-use and gaming disorders. It is assumed that primary and secondary reinforcers are involved in these processes. Despite the common use of pornography and gaming in the general population appetitive conditioning processes in this context are still not well studied. This study aims to compare appetitive conditioning processes using primary (pornographic) and secondary (monetary and gaming-related) rewards as unconditioned stimuli (UCS) in the general population. Additionally, it investigates the conditioning processes with gaming-related stimuli as this type of UCS was not used in previous studies. Thirty-one subjects participated in a differential conditioning procedure in which four geometric symbols were paired with either pornographic, monetary, or gaming-related rewards or with nothing to become conditioned stimuli (CS + porn, CS + game, CS + money, and CS-) in an functional magnetic resonance imaging study. We observed elevated arousal and valence ratings as well as skin conductance responses for each CS+ condition compared to the CS-. On the neural level, we found activations during the presentation of the CS + porn in the bilateral nucleus accumbens, right medial orbitofrontal cortex, and the right ventral anterior cingulate cortex compared to the CS-, but no significant activations during CS + money and CS + game compared to the CS-. These results indicate that different processes emerge depending on whether primary and secondary rewards are presented separately or together in the same experimental paradigm. Additionally, monetary and gaming-related stimuli seem to have a lower appetitive value than pornographic rewards.

Sex Differences in Sexual Motivation in Humans and Other Mammals: The Role of Conscious and Unconscious Processes

In self-report questionnaires, men report higher scores than women on variables such as desire for sex, frequency of sexual thoughts, number of sex partners, etc. Based on this, men are considered to have a higher level of sexual motivation than women. However, retrospective self-reports may be unsuitable for estimations of the inherent level of sexual motivation. We review data on automatic (unconsciously controlled) responses and measures of implicit motivation during exposure to sexual stimuli. These responses and measures are inaccessible to willful manipulations and make it possible to determine whether the sex difference in answers to questionnaires is replicated when volitional response manipulations are unlikely. We complement the human data with observations from some rodent and non-human primate species. The attentional resources allotted to stimuli with sexual relevance as well as genital responses to such stimuli are similar in men and women. Measures of implicit motivation also fail to detect any sex difference. Finally, the frequency of masturbation is superior in female infants before the age at which social expectations begin to determine behavior. Neither in rodents nor in non-human primates is there any clear-cut evidence for sex differences in motivation. It seems that males and females are similar with regard to the intensity of sexual motivation. The responses to questionnaires may be affected by social learning of sexual scripts and/or the inferior quality of sexual experiences in women, among other things.

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.

No significant effect of frequent online sexual behaviour on Pavlovian-to-instrumental transfer (PIT): Implications for compulsive sexual behaviour disorder

Reward based learning is broadly acknowledged to underpin the development and maintenance of addictive behaviour although the mechanism in sexual compulsivity is less understood. Using a Pavlovian-to-Instrumental Transfer (PIT) task we tested whether the motivational aspect of conditioned Pavlovian conditioned stimulus invigorated instrumental responding in relation to specific compatible monetary rewards. Performance on the task was analysed between two groups of males based on Low (N = 38) and High (N = 41) self-report online sexual behaviour (OSB). Psychometric tests including sexual compulsivity scale and behavioural activation/behavioural inhibition (BIS/BAS) were also administered to determine the relationship between OSB and general reward sensitivity. We show clear evidence of acquisition in the Pavlovian and instrumental conditioning phases. Specific transfer effect was greater in the High-OSB group although the difference compared to the Low-OSB group was non-significant. OSB negatively correlated with both BIS and BAS indicative of introversion and low reward sensitivity. OSB positively correlated with sexual compulsivity although it is unclear whether individuals in the High-OSB group considered their behaviour either excessive or problematic. These findings contribute to the ongoing debate regarding the nature of problematic OSB. Fundamental differences in motivational characteristics and mechanism contributing to compulsive behaviour in relation to high-OSB might indicate incompatibility with behavioural addiction models. PIT was not enhanced in high-OSB by appetitive conditioning, although problematic OSB could stem from failure to inhibit actions. Further research should investigate whether aversive conditioning differentially affects responding in high-OSB individuals, potentially explaining perseverant behaviour despite negative consequences.

Individual cortisol response to acute stress influences neural processing of sexual cues

BACKGROUND AND AIMS

Problematic pornography use can be conceptualized as an impulse control disorder or alternatively as a behavioral addiction. Stress is an important trigger in addiction, but less is known about the neural effect of stress in problematic pornography use. Therefore, we aimed at investigating the effect of stress during the anticipation and viewing of sexually explicit material while considering person characteristics related to potentially being at risk for developing problematic pornography use.

METHODS

In an fMRI study (n = 157 men, age: mean = 25.46, SD = 4.11) we used a sexual incentive delay task. A social stress test was used to induce stress in half of the participants. Salivary cortisol was repeatedly measured and person characteristics were considered moderating the effects of cortisol response.

RESULTS

We found no group differences in the neural responses during the anticipation phase, but a higher reactivity to sexual stimuli in the dACC in the stress group. Acute stress activated a pronounced cortisol response, which positively correlated with neural activations in the reward system (NAcc, dACC) to sexual cues. Further, the individual time spent on pornography use moderated the effect of cortisol in some regions of the reward system (dACC, mOFC).

DISCUSSION AND CONCLUSIONS

Our results suggest that acute stress related increases in cortisol can enhance the incentive value of cues announcing sexual stimuli. This might explain why acute stress is considered a trigger of pornography use and relapse and why individual stress response might be a risk factor for developing a problematic pornography use.

Differential brain responses to alcohol-related and natural rewards are associated with alcohol use and problems: Evidence for reward dysregulation

Multiple theoretical perspectives posit that drug use leads to biased valuation of drug-related reward, at the expense of naturally occurring rewarding activities (i.e., reward dysregulation). Recent research suggests that the comparative balance of drug-related and nondrug-related reward valuation is a powerful determinant of substance misuse and addiction. We examined differential neurophysiological responses-indexed with the P3 component of the event-related potential (ERP)-elicited by visual alcohol cues and cues depicting natural reward as a neurobiological indicator of problematic drinking. Nondependent, young adult drinkers (N = 143, aged 18-30 years) completed questionnaire measures assessing alcohol use and problems, and viewed alcohol cues (pictures of alcoholic beverages), high-arousing natural reward cues (erotica, adventure scenes), nonalcoholic beverage cues, and neutral scenes (e.g., household items) while ERPs were recorded. When examined separately, associations of P3-ERP reactivity to alcohol cues and natural reward cues with alcohol use and problems were weak. However, differential P3 response to the two types of cues (i.e., reward dysregulation P3) showed consistent and robust associations with all indices of alcohol use and problems and differentiated high-risk from lower-risk drinkers. The current results support the idea that the differential incentive-motivational value of alcohol, relative to naturally rewarding activities, is associated with increased risk for substance misuse and dependence, and highlight a novel neurophysiological indicator-the reward dysregulation P3-of this differential reward valuation.

The Biology of BDSM: A Systematic Review

INTRODUCTION

BDSM is an abbreviation used to reference the concepts of bondage and discipline, dominance and submission, sadism and masochism, enacted by power exchanges between consensual partners. In recent years, attention has shifted from the idea of BDSM as a pathological and tabooed niche practice towards viewing BDSM as a healthy form of intimacy.

AIM

This systematic review brings together all existing literature on the biology of BDSM and places it in a broader biological context.

METHODS

A systematic search was conducted on PubMed, Web of Science and PsycARTICLES, of which 10 articles are included and discussed in this systematic review.

RESULTS

There is evidence for cortisol changes in submissives as a result of a BDSM interaction, suggesting involvement of the physiological stress system. Endocannabinoid changes implicate the pleasure and reward system. In dominants, this biologically measured pleasure seemed to be dependent on power play rather than pain play. Testosterone and oxytocin are also implicated in BDSM, though their role is less evident. Research into brain region activity patterns related to BDSM interest suggests a role for the parietal operculum and ventral striatum in the context of the pleasure and reward system, the primary and secondary somatosensory cortex in the context of pain perception, empathy-related circuits such as the anterior insula, anterior midcingulate cortex and sensorimotor cortex and the left frontal cortex in the context of social and sexual interactions. Pain thresholds are shown to be higher in submissive individuals and a BDSM interaction may cause pain thresholds to rise in submissives as well.

CONCLUSION

BDSM interactions are complex and influenced by several psychological, social and biological processes. Though research is limited, there is emerging evidence for an interaction between several biological systems involved in these types of interests and activities. This means there is an important role for future research to replicate and supplement current results.

The Brain Activation-Based Sexual Image Classifier (BASIC): A Sensitive and Specific fMRI Activity Pattern for Sexual Image Processing

Previous studies suggest there is a complex relationship between sexual and general affective stimulus processing, which varies across individuals and situations. We examined whether sexual and general affective processing can be distinguished at the brain level. In addition, we explored to what degree possible distinctions are generalizable across individuals and different types of sexual stimuli, and whether they are limited to the engagement of lower-level processes, such as the detection of visual features. Data on sexual images, nonsexual positive and negative images, and neutral images from Wehrum et al. (2013) (N = 100) were reanalyzed using multivariate support vector machine models to create the brain activation-based sexual image classifier (BASIC) model. This model was tested for sensitivity, specificity, and generalizability in cross-validation (N = 100) and an independent test cohort (N = 18; Kragel et al. 2019). The BASIC model showed highly accurate performance (94–100%) in classifying sexual versus neutral or nonsexual affective images in both datasets with forced choice tests. Virtual lesions and tests of individual large-scale networks (e.g., visual or attention networks) show that individual networks are neither necessary nor sufficient to classify sexual versus nonsexual stimulus processing. Thus, responses to sexual images are distributed across brain systems.

Specific factors and methodological decisions influencing brain responses to sexual stimuli in women

Most of the neuroimaging studies on sexual behavior have been conducted with male participants, leading to men-based models of sexual arousal. Here, possible factors and methodological decisions that might influence brain responses to sexual stimuli, specifically for the inclusion of women, will be reviewed. Based on this review, we suggest that future studies consider the following factors: menstrual phase, hormonal contraception use, history of sexual or psychiatric disorders or diseases, and medication use. Moreover, when researching sexual arousal, we suggest future studies assess sexual orientation and preferences, that women should select visual sexual stimuli, and a longer duration than commonly used. This review is thought to represent a useful guideline for future research in sexual arousal, which hopefully will lead to a higher inclusion of women and therefore more accurate neurobiological models of sexual arousal.

The Impact of Negative Mood on Event-Related Potentials When Viewing Pornographic Pictures

Background: Negative affective states may increase the risk for problematic pornography use. Underlying neurophysiological mechanisms are, however, not completely understood. Previous research suggests that the participants' emotional state may affect neural processing of sexual stimuli. The aim of this study was to investigate neural correlates of negative affect-induced alterations in sexual cue reactivity in healthy men. The moderating effects of habitual porn consumption, trait sexual motivation, and symptoms of cybersex addiction were also considered. Method: Sixty-four healthy men engaged in a sexual cue reactivity task (passive viewing of explicit sexual pictures and neutral pictures depicting scenes of social interaction) during negative (n = 32) vs. neutral affect (n = 32), induced via tailored feedback on a performance task. Self-reported sexual arousal and event-related brain potentials indicated cue reactivity and motivated attention. Symptoms of cybersex addiction and trait sexual motivation were assessed with the help of the short Internet Addiction Test, adapted to online sexual activities, and the Trait Sexual Motivation Questionnaire. Results: Negative feedback increased negative affect after the performance task. While sexual pictures compared to neutral pictures elicited significantly larger P300 and late positive potential (LPP) amplitudes, there was no general effect of negative feedback on sexual stimuli-related P300 and LPP amplitudes. In the negative feedback group, men with higher solitary sexual motivation levels showed higher P300/LPP difference amplitudes for sexual stimuli compared to men with lower levels of solitary sexual motivation. The opposite effect was found in the group with neutral feedback. There was no link to other aspects of trait sexual motivation and symptoms of cybersex addiction. Conclusions: Results suggest that higher levels of solitary sexual motivation may enhance motivated attention toward sexual stimuli among men receiving negative performance feedback. Other characteristics of sexual behaviors and traits provided no exploratory value. Future studies extending onto men suffering from compulsive sexual behavior disorder will have to closer look at the neurophysiological bases of why and when some men develop an addictive pornography consumption.

Sexual incentive delay in the scanner: Sexual cue and reward processing, and links to problematic porn consumption and sexual motivation

BACKGROUND AND AIMS

The use of pornography, while unproblematic for the majority, can grow into addiction-like behavior which in its extreme form is labeled as compulsive sexual behavioral disorder in the ICD-11 (WHO, 2018). The aim of this study was to investigate the addiction-specific reactivity to cues in order to better understand underlying mechanisms in the development of this disorder.

METHODS

We have used an optimized Sexual Incentive Delay Task to study brain activity in reward associated brain areas during an anticipation phase (with cues predicting pornographic videos, control videos or no videos) and a corresponding delivery phase in healthy men. Correlations to indicators of problematic pornography use, the time spent on pornography use, and trait sexual motivation were analyzed.

RESULTS

The results of 74 men showed that reward-related brain areas (amygdala, dorsal cingulate cortex, orbitofrontal cortex, nucleus accumbens, thalamus, putamen, caudate nucleus, and insula) were significantly more activated by both the pornographic videos and the pornographic cues than by control videos and control cues, respectively. However, we found no relationship between these activations and indicators of problematic pornography use, time spent on pornography use, or with trait sexual motivation.

DISCUSSION AND CONCLUSIONS

The activity in reward-related brain areas to both visual sexual stimuli as well as cues indicates that optimization of the Sexual Incentive Delay Task was successful. Presumably, associations between reward-related brain activity and indicators for problematic or pathological pornography use might only occur in samples with increased levels and not in a rather healthy sample used in the present study.

Sex differences in neural responses to reward and the influences of individual reward and punishment sensitivity

BACKGROUND

Men and women show differences in sensitivity to reward and punishment, which may impact behavior in health and disease. However, the neural bases of these sex differences remain under-investigated. Here, by combining functional magnetic resonance imaging (fMRI) and a variant of the Monetary Incentive Delay Task (MIDT), we examined sex differences in the neural responses to wins and losses and how individual reward and punishment sensitivity modulates these regional activities.

METHODS

Thirty-sex men and 27 women participated in the fMRI study. We assessed sensitivity to punishment (SP) and sensitivity to reward (SR) with the Sensitivity to Punishment and Sensitivity to Reward Questionnaire (SPSRQ). In the MIDT, participants pressed a button to collect reward ($1, 1¢, or nil), with the reaction time window titrated across trials so participants achieved a success rate of approximately 67%. We processed the Imaging data with published routines and evaluated the results with a corrected threshold.

RESULTS

Women showed higher SP score than men and men showed higher SR score than women. Men relative to women showed higher response to the receipt of dollar or cent reward in bilateral orbitofrontal and visual cortex. Men as compared to women also showed higher response to dollar loss in bilateral orbitofrontal cortex. Further, in whole-brain regressions, women relative to men demonstrated more significant modulation by SP in the neural responses to wins and larger wins, and the sex differences were confirmed by slope tests.

CONCLUSIONS

Together, men showed higher SR and neural sensitivity to both wins, large or small, and losses than women. Individual differences in SP were associated with diminished neural responses to wins and larger wins in women only. These findings highlight how men and women may differ in reward-related brain activations in the MIDT and add to the imaging literature of sex differences in cognitive and affective functions.

Spotlight on Compulsive Sexual Behavior Disorder: A Systematic Review of Research on Women

PURPOSE OF REVIEW

World Health Organization recently included compulsive sexual behavior disorder (CSBD) to the upcoming 11th edition of International Classification of Diseases (6C72). Despite the potential benefits of this decision (eg, the acceleration of research in the field will allow the development of effective treatments), previous research focused mainly on men, and as a result, we do not have an accurate clinical picture of compulsive sexual behavior (CSB) among women. Therefore, in this systematic review, we aim to present available knowledge on this topical subject. Literature search was conducted in the guideline of PRISMA methodology. Studies were identified from multiple databases including Academic Search Ultimate, SocINDEX, PsycARTICLES, PsycINFO, PubMed, and MEDLINE. Out of a total of 10,531 articles identified and screened, 58 were included in this review. Included studies covered the following topics: prevalence and etiology of CSB, behavioral and cognitive processes involved, comorbidities, personality traits, psychosocial and interpersonal difficulties, traumatic experiences, and treatments.

RECENT FINDINGS

Available studies indicate that CSB symptom severity is lower in women than in men. Overall, women reported consuming pornography less often than men and exhibit lower rates of feeling urges to these materials. CSB symptoms (including problematic pornography use) have been found to be positively related to trait psychopathy, impulsivity, sensation seeking, attention-deficit/hyperactivity disorder symptoms, obsessive-compulsive disorder, pathological buying, sexual dysfunctions, general psychopathology, child sexual abuse, while negatively related to dispositional mindfulness.

SUMMARY

Conclusions that can be drawn from prior studies are considerably limited. There are no accurate estimates of the CSB prevalence or severity among women, and studies have been mostly conducted on non-clinical populations, which has limited application for women diagnosed with CSBD.

Approach bias for erotic stimuli among heterosexual female college students who use pornography

Repeated engagement in addictive behaviors may lead to relatively automatic action tendencies whereby individuals approach rather than avoid addictive stimuli. This study assessed whether an approach bias for erotic stimuli exists among heterosexual college-aged females who report using pornography. We tested 121 female undergraduates using an approach-avoidance task (AAT) employing both erotic and neutral stimuli, during which participants were instructed to push or pull a gaming joystick in response to image orientation. To simulate approach and avoidance movements, pulling the joystick enlarged the image and pushing shrunk the image. Severity of pornography use was assessed using the Brief Pornography Screener (BPS) and the Problematic Pornography Use Scale (PPUS). Participants demonstrated a significant approach bias of 24.81 ms for erotic stimuli as compared to neutral stimuli, and this approach bias significantly positively correlated with PPUS scores. Moreover, approach bias scores were significantly positively correlated with anhedonia (as assessed by the Snaith-Hamilton Pleasure Scale), indicating that the stronger the degree of approach for erotic stimuli, the more anhedonia that was observed. Anhedonia was not significantly associated with pornography use severity, however. Findings implicate both similarities and differences in problematic pornography use among female and male users. A limitation of the current study is that it assessed approach biases among only heterosexual females due to the erotic stimuli employed during the AAT. Future studies should examine approach biases among females of varying sexual orientations.