Anders Agmo

UiT The Arctic University of Norway · Department of Psychology

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 se...

Sexual motivation is an abstract concept referring to the mechanisms determining the responsivity to sexually relevant stimuli. This responsivity determines the likelihood of producing a sexual response and the intensity of that response. Both responsivity to stimuli and the likelihood of making a response as well as the intensity of response are c...

The generalized social concern with sexual harassment and nonconsensual sex makes it imperative to incorporate notions of consent in any analysis of human sexual interactions. Such interactions follow an ordered sequence of events, starting with the perception of a sexual incentive, followed by an approach to it, genital interaction, and eventually...

The low replicability of scientific studies has become an important issue. One possible cause is low representativeness of the experimental design employed. Already in the 1950’s, Egon Brunswick pointed out that experimental setups ideally should be based on a random sample of stimuli from the subjects’ natural environment or at least include basic...

Sexual behavior is, by necessity, sexually dimorphic. Males transfer sperm to females, whereas females receive sperm from males. Discussions of sex differences in copulatory behavior are consequently trivial. However, the behaviors associated with copulation, for example mate choice or postcopulatory reactions, may well be similar in males and fema...

In recent years, the Food and Drug Administration approved two drugs for the treatment of hypoactive sexual desire disorder in premenopausal women which have been tested in preclinical tests with positive effects on some appetitive sexual behavior in female rats. Some years after their commercial release, the effectiveness of both drugs in women is...

One of the consequences of sexual behavior is reproduction. Thus, this behavior is essential for the survival of the species. However, the individual engaged in sexual behavior is rarely aware of its reproductive consequences. In fact, the human is probably the only species in which sexual acts may be performed with the explicit purpose of reproduc...

Sexual motivation (desire) requires the simultaneous presence of an active central motive state and a stimulus with sexual significance. Once activated, sexual motivation leads to visceral responses and approach behaviors directed toward the emitter of the sexual stimulus. In humans, such behaviors follow cognitive evaluation of the context, includ...

Sexual incentive stimuli activate sexual motivation and heighten the level of general arousal. The sexual motive may induce the individual to approach the incentive, and eventually to initiate sexual acts. Both approach and the ensuing copulatory interaction further enhance general arousal. We present data from rodents and humans in support of thes...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Background Premature ejaculation is the most common sexual dysfunction in young men, and it often leads to reduced relationship satisfaction and quality of life. Aim To determine the role of central and peripheral α2-adrenoceptors in the control of ejaculation and sexual incentive motivation in rats. Methods Sexual incentive motivation was studie...

Although rats are known to emit ultrasonic vocalizations (USVs), it remains unclear whether these calls serve an auditory communication purpose. For USVs to be part of communication, the vocal signals will need to be a transfer of information between two or more conspecifics, and with the possibility to induce changes in the behavior of the recipie...

Masculinization and feminization of rat sexual behavior has been supposed to occur during a short postnatal period. However, much data have made it evident that these processes may continue until adolescence. In the present study, we evaluated whether androgen treatment of females from postnatal day 20 and onwards could alter sexual motivation and...

In classical rodent anxiety models, females usually display lower anxiety than males, whereas anxiety disorders are more prevalent in women. Perhaps this contradiction is caused by the use of behavioral models with low external validity. Therefore, we analyzed immediate reactions to a sudden 90 dB white noise in a seminatural environment. We observ...

This study evaluated the effect of stress during puberty on sexual motivation and the correlation between serum testosterone levels (T) and the absolute power of the theta electroencephalographic rhythms, recorded in the medial prefrontal cortex (mPFC) and basolateral amygdala (BLA) of adult male rats. Thirty males of the stressed group (SG, housed...

Gonadally intact female rats display sexual behaviors only during a portion of the estrus cycle. In standard experimental setups, the on- and offset of sexual behavior is gradual. However, in naturalistic settings, it is almost instantaneous. We assessed the changes in sociosexual behaviors at the beginning and end of behavioral estrus in ovariecto...

Intact female rats display sexual behaviors only during a portion of the estrus cycle. This portion, behavioral estrus, coincides with the proestrus/estrus phase as determined by vaginal cytology, and with peak serum concentrations of estradiol and progesterone. In standard experimental setups, intact females gradually changes from complete non-rec...

Sexual behavior is activated by motivation. An overwhelming majority of experimental studies of the intricacies of sexual motivation has been performed in rodents, most of them in rats. Sometimes it is desirable to generalize results obtained in this species to other species, particularly the human. It is hoped that studies of the neurobiology of r...

Sexually receptive female rats normally copulate with several males during estrus, and multiple paternity is common. Sperm competition is therefore likely to occur. One response to competitive mating is to enhance sperm output per ejaculation and another is to augment the number of ejaculations. The latter alternative requires more intense copulato...

Estrogens receptors (ER) are involved in several sociosexual behaviors and fear responses. In particular, the ERα is important for sexual behaviors, whereas ERβ modulates anxiolytic responses. Using shRNA directed either against the ERα or the ERβ RNAs (or containing luciferase control) encoded within an adeno-associated viral vector, we silenced t...

The behavioral effects of putative anxiolytic and anxiogenic drugs are usually evaluated in highly standardized tests. Here, we determined the effects of such drugs in rats housed in mixed sex groups in a seminatural environment. Sexually receptive female Wistar rats were treated with either the anxiolytic drug chlordiazepoxide (2 mg/kg), the anxio...

The behavioral effects of putative anxiolytic and anxiogenic drugs are usually evaluated in highly standardized tests. The external validity of these tests is unknown. In the present experiment, we determined the effects of the classical anxiolytic drug chlordiazepoxide and the purportedly anxiogenic adrenergic α2 antagonist yohimbine in mixed sex...

Estrogen receptors (ERs) are involved in sexual as well as non-sexual behaviors. In the present study we assessed the effects of stimuli inducing positive or negative affect on sociosexual, exploratory and fear-related behaviors of female rats housed in groups (4 females, 3 males) in a seminatural environment. Ovariectomized females were treated wi...

Acquisition of social dominance is important for social species including mice, for preferential access to foods and mates. Male mice establish social rank through agonistic behaviors, which are regulated by gonadal steroid hormone, testosterone, as its original form and aromatized form. It is well known that estrogen receptors (ERs), particularly...

Estradiol is known to modulate anxiety responses, being either anxiolytic or anxiogenic depending on the test procedure. Estradiol is supposed to increase sexual behaviors in safe environments and to inhibit them in threatening ones. In order to investigate this hypothesis, we used a procedure with external validity: the seminatural environment (SN...

This chapter outlines the incentive motivational framework used for the analysis of sexual behavior. It summarizes the endocrine and neural bases of this behavior. The chapter describes the importance of gonadal hormones in males and females, including humans. It discusses the principal brains sites involved in the control of sexual behavior, drug...

Sexual attraction has two components: Emission of sexually attractive stimuli and responsiveness to these stimuli. In rodents, olfactory stimuli are necessary but not sufficient for attraction. We argue that body odors are far superior to odors from excreta (urine, feces) as sexual attractants. Body odors are produced by sebaceous glands all over t...

This book contains 15 chapters that describe the physiological, behavioural and welfare parameters of smell and odour detection and processing in animals.

Le chlordiazépoxide a des effets anxiolytiques établis et la yohimbine a montré des effets anxiogènes chez les rongeurs. Contrairement aux procédures standards impliquant de tester des individus seuls ou par paires, souvent dans environnement appauvri, nous avons testé l’effet de ces substances dans un contexte ayant une validité externe. Des group...

Intrasexual competition is an important element of natural selection in which the most attractive conspecific has a considerable reproductive advantage over the others. The conspecifics that are approached first often become the preferred mate partners, and could thus from a biological perspective have a reproductive advantage. This underlines the...

Supplemental result. (DOCX)

Both male and female rats produce vocalizations in the presence of a potential sexual partner. In this study, we evaluated the role of vocalizations in sociosexual behaviors in an ecologically valid procedure. Three males and 4 females were housed in a seminatural environment. In each group, 1 or 2 males and females were devocalized, and the other...

We studied the differential role of estrogen receptors (ER) α and β in socio-sexual interactions among rats exposed to two positive stimuli. Ten groups of 7 rats (4 females and 3 males) were housed for 8 days in a semi-natural environment (SNE) consisting of an open area and a complex burrow system. The introduction of the rats into the SNE was set...

The influence of the duration of vaginocervical stimulation (VCS) on the electroencephalographic activity (EEG) of medial amygdala (MeA) and prefrontal cortex (PFC) in rats during proestrus-estrus (P-E) and diestrus (D) was examined. Using a glass syringe plunger, a constant force of 300 g was exerted against the cervix during 60 s. Relative power...

In the last few years, actions of estrogens on behavioral functions other than sexual have attracted increasing attention. However, few researches focus on the effects of estrogens in not-aversive contexts. We studied the differential role of estrogen receptors (ER) in rats exposed to positive stimuli. Ten groups of 7 rats each (4 females and 3 mal...

We studied the participation of GABA neurotransmission in the medial preoptic area (MPOA) in the onset of the pup retrieval response and nest building. Pregnant female rats were implanted with bilateral cannulae in the MPOA on 12 day of pregnancy, and on day 16 the females were hysterectomized-ovariectomized and given 200 μg/kg of estradiol benzoat...

When a prolonged observation of groups of rats in a seminatural environment is used as testing procedure, different behavioral patterns are shown compared with what observed in a pair housed in a small cage. Males and females copulate simultaneously, they show a promiscuously and random copulatory pattern. Females remain completely receptive from t...

The present study focused on the differential role of estrogen receptors (ER) α and β on socio-sexual interactions among rats. Ten groups of 7 rats (4 females and 3 males) were housed for 8 days in a semi-natural environment (SNE) consisting of a large open area and an adjacent burrow system. Females were ovariectomized about 2 weeks prior to the e...

Sexual arousal affects cognitive processing, which depends on the coordinated functioning among cortical areas. The aim of this research was to determine whether previous observation of videos with sexual content affects the degree of cortical electroencephalographic (EEG) coupling during performance of an executive task. Cortical EEG correlations...

The ability to silence the expression of gene products in a chemically, spatially, and temporally specific manner in the brains of animals has enabled key breakthroughs in the field of behavioral neuroscience. Using this technique, estrogen receptor alpha (ERα) has been specifically implicated in a multitude of behaviors in mice, including sexual,...

Both male and female rats produce 50 kHz ultrasonic vocalizations (USVs) in the presence of a sexual partner and during copulation. Previous studies showed that USVs have no incentive value for rats. In this study, we evaluated the role of USVs in behavior during copulation. Three groups of rats were used: sham males paired with sham females, devoc...

This study investigated the role of estrogen receptors alpha (ERα) in the ventromedial nucleus of the hypothalamus (VMN),the preoptic area (POA), the medial amygdala (MePD) and the bed nucleus of stria terminalis (BNST) in sociosexual behavior in female rats. This was done in two sets of experiments, with the VMN and POA investigated in the first s...

Previous studies in intact females revealed a sudden change in behavior immediately preceding the first lordosis displayed during estrus. The purpose of the present study was to determine whether this sudden change occurs also in ovariectomized females after sequential estrogen - progesterone treatment. Five groups of 7 rats (3 males and 4 females)...

Previous studies in intact females revealed a sudden change in behavior immediately preceding the first lordosis displayed during estrus. The purpose of the present study was to determine how this sudden change occurs in ovariectomized females after sequential estrogen-progesterone treatment, and if vocalizations played a role in this transition....

General arousal has been operationally defined as enhanced motor activity and enhanced intensity of response to sensory stimuli. Even though the effects of gonadal hormones on mating behavior have been much studied, their potential effect on generalized arousal, as defined above, has never been evaluated. In the present study we employed a thorough...

Groups of rats (3 males and 4 cycling females) were housed in a seminatural environment consisting of a burrow and a large open area for a period of 8 days. Sociosexual interactions were recorded whenever 1 or several females were in behavioral estrus. Male sociosexual behaviors occurred in bouts (periods of sexual activity followed by more than 60...

Intrasexual competition for access to a female mate is believed to be unusual in wild male rats, which suggests that female choosiness could be more important. It has been shown that females spend more time with one male than with others when tested in a multiple partner paradigm. The male of first entry is visited most. The role of ultrasonic voca...

Groups of 3 males and 4 females were housed in a seminatural environment for a period of 8 days. Female sociosexual behaviours were recorded and analysed from the beginning of behavioural oestrus (defined as the first lordosis response observed in the environment) until the end of oestrus (defined to occur at the moment of a lordosis that was not f...

Female sexual dysfunctions are a heterogeneous group of symptoms with unknown but probably varying etiology. Social factors may contribute both to the prevalence and to the origin of these dysfunctions. The present review focuses on female hypoactive sexual desire disorder, sexual arousal disorder and orgasmic disorder. These disorders are generall...

Rats emit ultrasonic vocalizations (USVs) of 22 kHz and 50 kHz before, during, and after copulation. The 50-kHz vocalizations can be subdivided into flat and frequency-modulated (FM) trill calls. In this study, the role of 50-kHz USVs in sexual incentive motivation in female rats was examined. USVs were recorded from sexually active males during th...

Endothelial nitric oxide synthase (eNOS) has an important role in erection, and it also affects aspects of sexual behavior. In this experiment, we determined whether a compound enhancing the activity of eNOS, Impaza, could stimulate any aspect of sexual behavior and increase penis length in rats with a high baseline of sexual activity. For comparis...

Ultrasonic vocalizations (USVs) are emitted in response to a sexual partner before, during, and after copulation. These vocalizations are the so-called 50-kHz USVs and can be subdivided into flat and frequency-modulated (FM) 50-kHz trill calls. In the present series of experiments, the potential unconditioned and conditioned incentive properties of...

In Experiment 1, four groups of male rats were subjected to Pavlovian conditioning of an approach response. In one group the reinforcer was one mount with a sexually receptive female and in another group it was one intromission. A third group was deprived of food for 8 h before every session and a fourth group was deprived for 16 h. These latter gr...

Introduction: Emotional stimuli elicit changes in the electroencephalographic (EEG) activity of several brain structures. Prefrontal cortex is involved in the processing of emotional stimuli and executive functions. The correlation analysis of EEG provides information about the functional coupling between areas. It is reasonable to expect that emo...

Ovariectomized females were given an infusion in the medial preoptic area (MPOA) of a viral vector carrying either a shRNA directed against the estrogen receptor α (ERα) or luciferase. The females were subjected to a test for sexual incentive motivation immediately followed by a test for receptivity and proceptive behaviors. Two weeks later they we...

The present study describes how the development of a pair bond modifies social, sexual and aggressive behavior. Five heterosexual pairs of marmosets, previously unknown to each other, were formed at the beginning of the study. At the onset of pairing, social, sexual, exploratory and aggressive behaviors were recorded for 40 min. The animals were th...

The present study describes how the development of a pair bond modifies social, sexual and aggressive behavior. Five heterosexual pairs of marmosets, previously unknown to each other, were formed at the beginning of the study. At the onset of pairing, social, sexual, exploratory and aggressive behaviors were recorded for 40 min. The animals were th...

Clinical data show that paroxetine causes sexual dysfunction in a substantial proportion of women taking this compound. This work was conducted to determine whether chronic paroxetine reduces sexual incentive motivation in female rats and whether this compound can modify any aspect of paced mating. The role of the 5-HT(1B) and 5-HT(2C) receptors in...

Sexual motivation and sexual arousal are widely used concepts. While there seem to be considerable agreement as to the meaning of sexual motivation, there is certain confusion about the exact meaning of sexual arousal. Some use it as a synonym to sexual motivation and others make it equivalent to erection or vaginal lubrication. An unresolved quest...

Hormones are important determinants of general arousal. They also control or modulate specific kinds of arousal. Estrogenic control of female sexual arousal is particularly well known. The molecular events associated with estrogenic action are partly elucidated, and the behavioral consequences of estrogen-dependent gene actions are beginning to be...

A neutral olfactory stimulus was employed as CS in a series of experiments with a sexually receptive female as UCS and the execution of an intromission as the UCR. Each experimental session lasted until the male ejaculated. The time the experimental subject spent in a zone adjacent to the source of the olfactory stimulus during the 10 s of CS prese...

Social recognition manifests itself in decreased investigation of a previously encountered individual. Estrogen receptor alpha (ERalpha) knock out mice show deficient social recognition and anxiety. These data show that the ERalpha is involved in these effects, but they do not say anything about the brain sites important for these effects. In this...

The establishment and maintenance of stable, long-term male-female relationships, or pair-bonds, are marked by high levels of mutual attraction, selective preference for the partner, and high rates of sociosexual behavior. Central oxytocin (OT) affects social preference and partner-directed social behavior in rodents, but the role of this neuropept...

The display of copulatory behaviors usually requires the presence of a mate and is, therefore, preceded by a search for and approach to a potential partner. The intensity of approach behaviors is determined by a process labeled sexual incentive motivation. Although it is known that female sexual motivation depends on estrogens, their site of action...

In Experiment 1 castrated male rats were implanted with a Silastic capsule containing either E or cholesterol (CHOL) 35 days after castration. They were then tested for sexual incentive motivation and copulatory behaviors every 5th day for 3 weeks. None of the treatments affected sexual incentive motivation. After the last test, all subjects were i...

The effects of estradiol and progesterone on social recognition were evaluated in a habituation-dishabituation procedure. Ovariectomized female rats were either given 18 microg/kg of estradiol benzoate followed by progesterone, 1 mg/rat, 48 h later or oil. The test consisted of 4 consecutive exposures to a juvenile rat and a final exposure to a nov...

Introduction: Earlier studies have shown that sildenafil may modify some aspects of male rat sexual behavior and sexual incentive motivation. Stimulation of endothelial nitric oxide synthase (eNOS) has also been reported to affect sexual motivation in old rats. Aim: To determine the effects of sildenafil and a compound stimulating eNOS on copula...

Paced mating induces positive affect as revealed by conditioned place preference (CPP) in female rats. It has been suggested that endogenous opioids are involved in the generation of this positive affect since systemic administration of the opioid antagonist naloxone blocks mating-induced CPP. Several brain structures, including the medial preoptic...

Several proerectile drugs act on the nitric oxide-cyclic guanosine monophosphate pathway, which is known to influence rat copulatory behavior. In the present study we evaluated the effects of two proerectile compounds, one (Impaza) acting on endothelial nitric oxide synthase, and the other (sildenafil) on phosphodiesterase 5, on sexual incentive mo...

Permanent bilateral lesions of the medial preoptic area anterior hypothalamus (MPOA/AH) produce a drastic inhibition of male sexual behavior in all species studied to date. The present experiment was designed to evaluate if temporal inactivation of the MPOA/AH by infusions of lidocaine also inhibits sexual behavior in male rats. This would allow us...

Social and sexual incentive motivation, defined as the intensity of approach to a social and a sexual incentive, respectively, were studied in female Swiss Webster mice. In the first experiment, the social incentive was a castrated mouse of the same strain as the females, whereas the sexual incentive was an intact male mouse of the same strain. Ova...

Motivation can be defined as a class of central nervous processes determining the likelihood of display of a behavior and the intensity of the behavior if displayed. All behavior is, according to this definition, caused and controlled by motivation. Although the concept of motivation eventually could be replaced by an entirely mechanistic explanati...

This chapter focuses on simple incentive stimuli of possible importance for sexual behavior in nonhuman animals. Nonhuman mammals may respond to stimuli or to qualities of stimuli that human sensory systems are unable to detect. Some of these stimuli or stimulus qualities may have sexual incentive properties. Two groups of stimuli that are supposed...

This chapter focuses on same-sex behaviors in nonhuman animals. Preference for having sex with partners of one's own sex is called homosexuality in contemporary society. There are not many examples of same-sex preferences among nonhuman mammals. Indeed, such preferences have been firmly established only in one subpopulation of rams and in one prima...

This chapter focuses on dysfunctions and/or abnormal sexual behaviors. It presents a discussion on the notions of, and differences among normal, abnormal, functional, and dysfunctional. Although rarely defined in the clinical literature, the habitual meaning of “normal” seems to be “close to average.” Anything far from the average is correspondingl...

This chapter describes how sexual behaviors can be modified by experience. Sexual responses can habituate with repeated presentations of a constant stimulus, and they can be sensitized by irrelevant stimuli. Negative alliesthesia is another process that may temporarily affect a stimulus's capacity to activate sexual approach and copulatory behavior...

Hyperactive sexual desire and the paraphilias represent aspects of human sexual behavior that are morally questionable in contemporary society. This chapter reviews the current understanding of high sexual desire and paraphilias including the proposed diagnostic criteria, epidemiology, and treatment. Hyperactive sexual desire is an ambiguous concep...

This chapter examines the brain structures involved in the control of sexual behavior. In the male, the medial preoptic area is essential for male sexual behavior. It is also possible that the copulatory motor patterns are under preoptic control. The ventromedial nucleus of the hypothalamus may exert some inhibitory action on male sexual behaviors....

This chapter begins with a presentation of the theoretical model providing a basis for organization of the present knowledge. Existing scientific information about sexuality is so vast that it is impossible to grasp its essence without having a theoretical structure that can impose order upon it. It outlines a model that describes how internal stat...

This chapter discusses the deliberate omissions of arguments and propositions related to various aspects of sexual behavior in the book. Many arguments that could have been made in support for a proposition were not made in the book, whereas sometimes arguments that could have been made against a proposition were not made. It states that the argume...

This chapter focuses on a sexual dysfunction, hypoactive sexual desire disorder, and provides an analysis of its diagnosis, prevalence, etiology, and potential treatments. The etiology of hypoactive sexual desire disorder is unknown. Endocrine changes do not seem to be involved, and no other organismic cause has been found. An incentive motivation/...