Detailed analysis of the male copulatory motor pattern in mammals: Hormonal bases

Moralí, Gabriela; Soto, M.A.; Contreras, J. L.; Arteaga, Marcela; González-Vidal, Marı́a Dolores; Beyer, Carlos

doi:10.1111/1467-9450.00346

Cited by 28 publications

(13 citation statements)

References 23 publications

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“…In both rodents and lagomorphs, mounting and thrusting is observed in both males and females while lordosis is observed in females only [Morali and Beyer, 1992; Northcutt and Lonstein, 2008]. Small differences are present such that in contrast to rats, previous sexual experience does not affect mounting behavior in rabbits [Contreras and Beyer 1979] and SDN-POA lesions in male rabbits as well as hormonal manipulations in female rabbits do alter the pelvic thrusting behavior [Morali et al 2003]. Thus the sexual dimorphism in the SDN-POA of rabbits appears to be highly derived, and its effects on behavior remain unclear.…”

Section: Discussionmentioning

confidence: 99%

Sexual Dimorphism in the Brain of the Monogamous California Mouse (Peromyscus californicus)

Campi

Jameson

Trainor³

2013

Brain Behav Evol

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Sex differences in behavior and morphology are usually assumed to be stronger in polygynous species compared to monogamous species. A few brain structures have been identified as sexually dimorphic in polygynous rodent species, but it is less clear whether these differences persist in monogamous species. California mice are among the 5% or less of mammals that are considered to be monogamous and as such provide an ideal model to examine sexual dimorphism in neuroanatomy. In the present study we compared the volume of hypothalamic- and limbic-associated regions in female and male California mice for sexual dimorphism. We also used tyrosine hydroxylase (TH) immunohistochemistry to compare the number of dopamine neurons in the ventral tegmental area (VTA) in female and male California mice. Additionally, tract tracing was used to accurately delineate the boundaries of the VTA. The total volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA), the principal nucleus of the bed nucleus of the stria terminalis (BNST), and the posterodorsal medial amygdala (MEA) was larger in males compared to females. In the SDN-POA we found that the magnitude of sex differences in the California mouse were intermediate between the large differences observed in promiscuous meadow voles and rats and the absence of significant differences in monogamous prairie voles. However, the magnitude of sex differences in MEA and the BNST were comparable to polygynous species. No sex differences were observed in the volume of the whole brain, the VTA, the nucleus accumbens or the number of TH-ir neurons in the VTA. These data show that despite a monogamous social organization, sexual dimorphisms that have been reported in polygynous rodents extend to California mice. Our data suggest that sex differences in brain structures such as the SDN-POA persist across species with different social organizations and may be an evolutionarily conserved characteristic of mammalian brains.

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Section: Discussionmentioning

confidence: 99%

Sexual Dimorphism in the Brain of the Monogamous California Mouse (Peromyscus californicus)

Campi

Jameson

Trainor³

2013

Brain Behav Evol

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“…Tests were videotaped and subsequently viewed to score males’ investigation of the female (defined as nasal contact with the body of the estrous female) as well as mounting of the female. Mounts with slow rhythmic pelvic thrusting were distinguished and scored as intromissions (Baum et al, 1994; Morali et al, 2003). …”

Section: Methodsmentioning

confidence: 99%

Optogenetic Activation of Accessory Olfactory Bulb Input to the Forebrain Differentially Modulates Investigation of Opposite versus Same-Sex Urinary Chemosignals and Stimulates Mating in Male Mice

Kunkhyen

McCarthy

Korzan

et al. 2017

eNeuro

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Surgical or genetic disruption of vomeronasal organ (VNO)-accessory olfactory bulb (AOB) function previously eliminated the ability of male mice to processes pheromones that elicit territorial behavior and aggression. By contrast, neither disruption significantly affected mating behaviors, although VNO lesions reduced males’ investigation of nonvolatile female pheromones. We explored the contribution of VNO-AOB pheromonal processing to male courtship using optogenetic activation of AOB projections to the forebrain. Protocadherin-Cre male transgenic mice received bilateral AOB infections with channelrhodopsin2 (ChR2) viral vectors, and an optical fiber was implanted above the AOB. In olfactory choice tests, males preferred estrous female urine (EFU) over water; however, this preference was eliminated when diluted (5%) EFU was substituted for 100% EFU. Optogenetic AOB activation concurrent with nasal contact significantly augmented males’ investigation compared to 5% EFU alone. Conversely, concurrent optogenetic AOB activation significantly reduced males’ nasal investigation of diluted urine from gonadally intact males (5% IMU) compared to 5% IMU alone. These divergent effects of AOB optogenetic activation were lost when males were prevented from making direct nasal contact. Optogenetic AOB stimulation also failed to augment males’ nasal investigation of deionized water or of food odors. Finally, during mating tests, optogenetic AOB stimulation delivered for 30 s when the male was in physical contact with an estrous female significantly facilitated the occurrence of penile intromission. Our results suggest that VNO-AOB signaling differentially modifies males’ motivation to seek out female vs male urinary pheromones while augmenting males’ sexual arousal leading to intromission and improved reproductive performance.

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“…The mechanism responsible for the main effect of vomeronasal organ removal found in male rats—reduced capacity to perform intromission—is easy to explain in motivational terms. It must be recalled that a mount and an intromission are identical motor patterns until penetration is initiated 85,86 . At that moment, pelvic anteroposterior thrusting stops and is replaced by a strong forward thrust.…”

Section: A Short Analysis Of Sexual‐incentive Stimuli and Their Effectsmentioning

confidence: 99%

“…It must be recalled that a mount and an intromission are identical motor patterns until penetration is initiated. 85,86 At that moment, pelvic anteroposterior thrusting stops and is replaced by a strong forward thrust. It is believed that the critical stimulus for the forward thrust is sensory stimulation caused by penile contact with the vaginal orifice.…”

Section: A Short Analysis Of Sexual-incentive Stimuli and Their Effectsmentioning

confidence: 99%

Motivational Influences on the Degree and Direction of Sexual Attraction

Hernández‐González

Guevara

Ågmo

2008

Annals of the New York Academy of Sciences

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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 explanation of the causes of behavior, in terms of neural events, such explanations would be overly complex for everyday use. This is particularly the case with regard to the momentaneous fluctuations in the intensity of a behavior, like those occurring during copulation in rats. Thus, the concept of motivation will remain useful even when mechanistic explanations become available. Even though the propensity to perform sexual responses is determined by sexual motivation, another element is required for the execution of such responses. This other element is an appropriate stimulus, a sexual incentive. For a male rat, an appropriate incentive could be a sexually receptive female. For a human, it could be a mental representation of a sexual partner. The incentive activates approach behaviors, and the intensity of these behaviors will be determined by motivation and by the quality of the incentive stimulus, its attractivity. Much work has been done with the purpose of identifying the nature of the incentive stimulus or stimuli emitted by rats and other mammals. While visual stimuli seem to be of limited importance, auditory and particularly olfactory stimuli have been found to have incentive properties. Soluble chemicals may be important for some aspects of copulation, but copulatory motor patterns are basically under the control of tactile stimuli. The processing of sexual incentives in the rat brain has been studied with electroencephalographic techniques, and data show that the prefrontal cortex (PFC) participates in the identification of sexual incentives. Furthermore, there are important differences between the medial and orbital frontal cortices. The medial PFC, as well as the ventral tegmental area, also seem to participate in the generation of pelvic thrusting.

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Detailed analysis of the male copulatory motor pattern in mammals: Hormonal bases

Cited by 28 publications

References 23 publications

Sexual Dimorphism in the Brain of the Monogamous California Mouse (Peromyscus californicus)

Sexual Dimorphism in the Brain of the Monogamous California Mouse (Peromyscus californicus)

Optogenetic Activation of Accessory Olfactory Bulb Input to the Forebrain Differentially Modulates Investigation of Opposite versus Same-Sex Urinary Chemosignals and Stimulates Mating in Male Mice

Motivational Influences on the Degree and Direction of Sexual Attraction

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