REVIEW: New Electroencephalogram (EEG) Neuroimaging Methods of Analyzing Brain Activity Applicable to the Study of Human Sexual Response

Balance-energy of resting state network in obsessive-compulsive disorder

Stability of the brain functional network is directly linked to organization of synchronous and anti-synchronous activities. Nevertheless, impact of arrangement of positive and negative links called links topology requires to be well understood. In this study, we investigated how topology of the functional links reduce balance-energy of the brain network in obsessive-compulsive disorder (OCD) and push the network to a more stable state as compared to healthy controls. Therefore, functional associations between the regions were measured using the phase synchrony between the EEG activities. Subsequently, balance-energy of the brain functional network was estimated based on the quality of triadic interactions. Occurrence rates of four different types of triadic interactions including weak and strong balanced, and unbalanced interactions were compared. In addition, impact of the links topology was also investigated by looking at the tendency of positive and negative links to making hubs. Our results showed although the number of positive and negative links were not statistically different between OCD and healthy controls, but positive links in OCDs' brain networks have more tendency to make hub. Moreover, lower number of unbalanced triads and higher number of strongly balanced triad reduced the balance-energy in OCDs' brain networks that conceptually has less requirement to change. We hope these findings could shed a light on better understanding of brain functional network in OCD.

Neuroelectric Correlates of Human Sexuality: A Review and Meta-Analysis

Many reviews on sexual arousal in humans focus on different brain imaging methods and behavioral observations. Although neurotransmission in the brain is mainly performed through electrochemical signals, there are no systematic reviews of the electrophysiological correlates of sexual arousal. We performed a systematic search on this subject and reviewed 255 studies including various electrophysiological methods. Our results show how neuroelectric signals have been used to investigate genital somatotopy as well as basic genital physiology during sexual arousal and how cortical electric signals have been recorded during orgasm. Moreover, experiments on the interactions of cognition and sexual arousal in healthy subjects and in individuals with abnormal sexual preferences were analyzed as well as case studies on sexual disturbances associated with diseases of the nervous system. In addition, 25 studies focusing on brain potentials during the interaction of cognition and sexual arousal were eligible for meta-analysis. The results showed significant effect sizes for specific brain potentials during sexual stimulation (P3: Cohen's d = 1.82, N = 300, LPP: Cohen's d = 2.30, N = 510) with high heterogeneity between the combined studies. Taken together, our review shows how neuroelectric methods can consistently differentiate sexual arousal from other emotional states.

Electrophysiological Evidence of Enhanced Processing of Novel Pornographic Images in Individuals With Tendencies Toward Problematic Internet Pornography Use

Novelty seeking is regarded as a core feature in substance use disorders. However, few studies thus far have investigated this feature in problematic Internet pornography use (PIPU). The main aim of the present study was to examine group differences in electrophysiological activity associated with novelty processing in participants with high tendencies toward PIPU vs. low tendencies using event-related potentials (ERPs). Twenty-seven participants with high tendencies toward PIPU and 25 with low tendencies toward PIPU completed a modified three-stimulus oddball task while electroencephalogram (EEG) was recorded. Participants were instructed to detect neutral target stimuli from distracting stimuli. The distracting stimuli contained a familiar sexual stimulus and a set of novel sexual stimuli. The novel-familiar difference waves were calculated to identify specific group difference in novelty effect. While both groups demonstrated a sustained novelty effect in the late positive potential (LPP) within the 500–800 ms time windows, the novelty effect was greater in the high tendencies toward PIPU group than in the low tendencies toward PIPU group. This result suggests that individuals with high tendencies toward PIPU allocate more attentional resources for novelty processing. Enhanced brain responding to novel sexual stimuli may facilitate pornographic consumption and play an essential role in the development and maintenance of PIPU.

Complexity of information processing in obsessive-compulsive disorder based on fractal analysis of EEG signal

The human brain is considered as a self-organizing system with self-similarities at various temporal and spatial scales called "fractals". In this scale-free system, it is possible to decode the complexity of information processing using fractal behavior. For instance, the complexity of information processing in the brain can be evaluated by fractal dimensions (FDs). However, it is unclear how over-elaboration of information processing impacts the dimensionality of its fractal behavior. In this study, we hypothesized that FDs of electroencephalogram (EEG) in obsessive-compulsive disorder (OCD) should be higher than healthy controls (HCs) because of exaggeration of information processing mainly in the frontal regions. Therefore, a group of 39 OCDs (age: 34.76±8.22, 25 female, 3 left-handed) and 19 HCs (age: 31.94±8.22, 11 female, 1 left-handed) were recruited and their brain activities were recorded using a 19-channel EEG recorder in the eyes-open resting-state condition. Subsequently, fractal dimensions of the cleaned EEG data were calculated using Katz's method in a frequency band-specific manner. After the test of normality, significant changes in the OCDs as compared to the HCs were calculated using a two-sample t-test. OCDs showed higher FDs in the frontal regions in all frequency bands as compared to HCs. Although, significant increases were only observed in the beta and lower gamma bands, mainly at the high beta. Interestingly, neurophysiological findings also show association with severity of obsessive behaviors. The results demonstrate that complexity of information processing in the brain follows an intimate nature of structural and functional impairments of the brain in OCD.

Sexuality in women with endometriosis: a critical narrative review

Endometriosis is a chronic gynecological disease that generally affects young and sexually active women in different stages of their development and sexual life. Because endometriosis affects about 5-10% of women in reproductive age, it is possible to estimate that about 2-4% of those who are sexually active may suffer from sexual dysfunction caused by this disease. Surgical and pharmacological treatments of endometriosis can improve the patient's sexual function in the medium and long term, but not necessarily lead to a definitive resolution of the sexual issue. For this reason, the ideal treatment should be conducted by a multidisciplinary team, with the aim to improve overall sexual functioning and not only to reduce the painful symptoms during intercourse. In light of these considerations, the aim of this narrative review was to provide a general overview about the impact of endometriosis on sexuality of women affected and the effectiveness of surgical and pharmacological treatments in improving sexual function.

Contemporary and Novel Imaging Studies for the Evaluation of Erectile Dysfunction

Traditionally, it was thought that the pathogenesis of erectile dysfunction (ED) can be divided into psychological and organic factors. However, recent literature supports the development and progression of ED due to multidimensional alterations of a complex interplay of central and peripheral systems, from neural cognitive and efferent networks to loco-regional neuro-hormonal factors which are responsible for impaired penile vascular hemodynamics and ensuing lack of, or suboptimal, blood flow into the penis and/or veno-occlusive dysfunction. It is recognised that ED is strongly correlated with cardiovascular health and published clinical guidelines advocate screening for cardiovascular and metabolic risk factors in men presenting with ED. Over the past few decades, various imaging modalities have been developed and utilised to provide objective evaluation for ED to better characterise the state of penile health and exclude psychogenic components. The following article evaluates current and emerging imaging diagnostic tools for ED.

Differential pattern of brain functional connectome in obsessive-compulsive disorder versus healthy controls

Researchers believe that recognition of functional impairment in some of brain networks such as frontal-parietal, default mode network (DMN), anterior medial prefrontal cortex (MPFC) and striatal structures could be a beneficial biomarker for diagnosis of obsessive-compulsive disorder (OCD). Although it is well recognized brain functional connectome in OCD patients shows changes, debate still remains on characteristics of the changes. In this regard, little has been done so far to statistically assess the altered pattern using whole brain electroencephalography. In this study, resting state EEG data of 39 outpatients with OCD and 19 healthy controls (HC) were recorded. After, brain functional network was estimated from the cleaned EEG data using the weighted phase lag index algorithm. Output matrices of OCD group and HCs were then statistically compared to represent meaningful differences. Significant differences in functional connectivity pattern were demonstrated in several regions. As expected the most significant changes were observed in frontal cortex, more significant in frontal-temporal connections (between F3 and F7, and T5 regions). These results in OCD patients are consistent with previous studies and confirm the role of frontal and temporal brain regions in OCD.

Fantasy-Driven Versus Contact-Driven Users of Child Sexual Exploitation Material: Offender Classification and Implications for Their Risk Assessment

Since the advent of the Internet, convictions for the possession, display, trading, and distribution of child sexual exploitation material (CSEM) have risen steadily, but little is known about their appropriate assessment and treatment, especially concerning their risk of reoffending. It has been suggested that a conceptual distinction of fantasy- versus contact-driven CSEM users might be of merit. Sixty-eight offenders recruited from sex offender treatment providers were assessed via an anonymous computer survey including a variety of clinical and risk-related variables; the findings showed differences in the psychological profiles between CSEM users and contact child sex offenders. Numerical and spatial methods of data analysis were used to identify subgroups of CSEM users; these confirmed the twofold distinction of fantasy- versus contact-driven offending. The spatial representation of participants identified three dimensions as crucial in the classification of these subgroups: direct sexual contact with a minor, possession of fantasy-generating material, and social contact with other users with a sexual interest in minors; potentially differentiating distinct offender subgroups with different risks and needs. The current study informed the development of an empirical model of CSEM users that could aid in the assessment of risk of reoffending and cross-over to contact sex offending.

Sexual function in endometriosis patients and their partners: effect of the disease and consequences of treatment

BACKGROUND

Sexual function is an important aspect of health and quality of life and is influenced by both medical conditions and health-care interventions, especially when gynecologic disorders are involved. Coital pain is among the main factors that affect sexual functioning, and this symptom is reported by almost half of women suffering from endometriosis. However, sexuality is a complex phenomenon driven by social, psychological and biological/hormonal factors and the presence of endometriosis might further affect domains of sexual function and the quality of a sexual relationship.

OBJECTIVE AND RATIONALE

The objective of this report is to review the current state of knowledge on the impact that endometriosis and its treatments have on the sexual function of women and their sexual partners.

SEARCH METHODS

A systematic literature search was performed to identify studies evaluating sexual function in endometriosis patients, and a narrative analysis of results is presented. The review discusses relevant quantitative and qualitative studies analyzing the effect of endometriosis and its hormonal and surgical treatments on measures of sexual function and quality of sexual relationship.

OUTCOMES

Endometriosis negatively affects different domains of sexual function, and the presence of dyspareunia is not the only determinant of sexual health in these women. Chronic pelvic pain, advanced stages of disease and the presence of physical and mental comorbidities affect sexual function, as well as personality traits and women's expectations. Although a number of studies have evaluated the effect of surgery and hormonal treatment on deep dyspareunia, overall sexual function and quality of the relationship with the partner are often under-investigated.

WIDER IMPLICATIONS

Multiple clinical and personal determinants affect sexual function in women with endometriosis, with potentially negative consequences on the sexual function of partners and quality of the relationship. Additional prospective and longitudinal investigations are warranted using specific instruments to analyze biopsychosocial variables of sexual pain in endometriosis patients and the effects that actual treatments have on measures of quality of sexual function and relationship.

The common neural bases between sexual desire and love: a multilevel kernel density fMRI analysis

INTRODUCTION

One of the most difficult dilemmas in relationship science and couple therapy concerns the interaction between sexual desire and love. As two mental states of intense longing for union with others, sexual desire and love are, in fact, often difficult to disentangle from one another.

AIM

The present review aims to help understand the differences and similarities between these two mental states using a comprehensive statistical meta-analyses of all functional magnetic resonance imaging (fMRI) studies on sexual desire and love.

METHODS

Systematic retrospective review of pertinent neuroimaging literature.

MAIN OUTCOME MEASURES

Review of published literature on fMRI studies illustrating brain regions associated with love and sexual desire to date.

RESULTS

Sexual desire and love not only show differences but also recruit a striking common set of brain areas that mediate somatosensory integration, reward expectation, and social cognition. More precisely, a significant posterior-to-anterior insular pattern appears to track sexual desire and love progressively.

CONCLUSIONS

This specific pattern of activation suggests that love builds upon a neural circuit for emotions and pleasure, adding regions associated with reward expectancy, habit formation, and feature detection. In particular, the shared activation within the insula, with a posterior-to-anterior pattern, from desire to love, suggests that love grows out of and is a more abstract representation of the pleasant sensorimotor experiences that characterize desire. From these results, one may consider desire and love on a spectrum that evolves from integrative representations of affective visceral sensations to an ultimate representation of feelings incorporating mechanisms of reward expectancy and habit learning.

Intention, false beliefs, and delusional jealousy: insights into the right hemisphere from neurological patients and neuroimaging studies

Jealousy sits high atop of a list comprised of the most human emotional experiences, although its nature, rationale, and origin are poorly understood. In the past decade, a series of neurological case reports and neuroimaging findings have been particularly helpful in piecing together jealousy’s puzzle. In order to understand and quantify the neurological factors that might be important in jealousy, we reviewed the current literature in this specific field. We made an electronic search, and examined all literature with at least an English abstract, through Mars 2010. The search identified a total of 20 neurological patients, who experienced jealousy in relation with a neurological disorder; and 22 healthy individuals, who experienced jealousy under experimental neuroimaging settings. Most of the clinical cases of reported jealousy after a stroke had delusional-type jealousy. Right hemispheric stroke was the most frequently reported neurological disorder in these patients, although there was a wide range of more diffuse neurological disorders that may be reported to be associated with different other types of jealousy. This is in line with recent neuroimaging data on false beliefs, moral judgments, and intention [mis]understanding. Together the present findings provide physicians and psychologists with a potential for high impact in understanding the neural mechanisms and treatment of jealousy. By combining findings from case reports and neuroimaging data, the present article allows for a novel and unique perspective, and explores new directions into the neurological jealous mind.

Neuroimaging of love: fMRI meta-analysis evidence toward new perspectives in sexual medicine

INTRODUCTION

Brain imaging is becoming a powerful tool in the study of human cerebral functions related to close personal relationships. Outside of subcortical structures traditionally thought to be involved in reward-related systems, a wide range of neuroimaging studies in relationship science indicate a prominent role for different cortical networks and cognitive factors. Thus, the field needs a better anatomical/network/whole-brain model to help translate scientific knowledge from lab bench to clinical models and ultimately to the patients suffering from disorders associated with love and couple relationships.

AIM

The aim of the present review is to provide a review across wide range of functional magnetic resonance imaging (fMRI) studies to critically identify the cortical networks associated with passionate love, and to compare and contrast it with other types of love (such as maternal love and unconditional love for persons with intellectual disabilities).

METHODS

Retrospective review of pertinent neuroimaging literature.

MAIN OUTCOME MEASURES

Review of published literature on fMRI studies of love illustrating brain regions associated with different forms of love.

RESULTS

Although all fMRI studies of love point to the subcortical dopaminergic reward-related brain systems (involving dopamine and oxytocin receptors) for motivating individuals in pair-bonding, the present meta-analysis newly demonstrated that different types of love involve distinct cerebral networks, including those for higher cognitive functions such as social cognition and bodily self-representation.

CONCLUSIONS

These metaresults provide the first stages of a global neuroanatomical model of cortical networks involved in emotions related to different aspects of love. Developing this model in future studies should be helpful for advancing clinical approaches helpful in sexual medicine and couple therapy.

Understanding actions of others: the electrodynamics of the left and right hemispheres. A high-density EEG neuroimaging study

Background

When we observe an individual performing a motor act (e.g. grasping a cup) we get two types of information on the basis of how the motor act is done and the context: what the agent is doing (i.e. grasping) and the intention underlying it (i.e. grasping for drinking). Here we examined the temporal dynamics of the brain activations that follow the observation of a motor act and underlie the observer's capacity to understand what the agent is doing and why.

Methodology/Principal Findings

Volunteers were presented with two-frame video-clips. The first frame (T0) showed an object with or without context; the second frame (T1) showed a hand interacting with the object. The volunteers were instructed to understand the intention of the observed actions while their brain activity was recorded with a high-density 128-channel EEG system. Visual event-related potentials (VEPs) were recorded time-locked with the frame showing the hand-object interaction (T1). The data were analyzed by using electrical neuroimaging, which combines a cluster analysis performed on the group-averaged VEPs with the localization of the cortical sources that give rise to different spatio-temporal states of the global electrical field. Electrical neuroimaging results revealed four major steps: 1) bilateral posterior cortical activations; 2) a strong activation of the left posterior temporal and inferior parietal cortices with almost a complete disappearance of activations in the right hemisphere; 3) a significant increase of the activations of the right temporo-parietal region with simultaneously co-active left hemispheric sources, and 4) a significant global decrease of cortical activity accompanied by the appearance of activation of the orbito-frontal cortex.

Conclusions/Significance

We conclude that the early striking left hemisphere involvement is due to the activation of a lateralized action-observation/action execution network. The activation of this lateralized network mediates the understanding of the goal of object-directed motor acts (mirror mechanism). The successive right hemisphere activation indicates that this hemisphere plays an important role in understanding the intention of others.