Behavioral Neuroscience and Sexual Behavior Development

Behavioral neuroscience

Exploration of the brain pathways that lead to different behaviors.

Common behaviors studied

Generally, common behaviors within and often between species.

Motivated behaviors

Behaviors that have an evolutionary history and a genetic basis, which may be modified by experience.

Active areas of research in behavioral neuroscience

Feeding, sex, aggression, day/night rhythms, and sleep.

Neural mechanisms

The underlying processes in the brain that influence emotions, learning, memory, and motivation.

Research techniques in behavioral neuroscience

Brain imaging, electrophysiology, and behavioral experiments.

Sexual differentiation in embryos

In the absence of the Y chromosome and SRY gene, the default pathway leads to the development of ovaries and feminization.

SRY gene

Triggers the development of testes, which produce testosterone, leading to the masculinization of the embryo.

Sexually dimorphic nucleus (SDN)

A brain structure larger in males than in females, involved in regulating male-typical sexual behaviors.

Hormonal exposure

Influences the size and structure of the SDN during critical periods of brain development.

Prairie voles

Monogamous voles that form long-term pair bonds, studied for understanding sexual behavior and bonding.

Montane voles

Typically promiscuous voles used to compare with prairie voles in studies of sexual behavior.

Oxytocin receptors

Higher densities in prairie voles' brain regions associated with reward and bonding, influencing their monogamous behavior.

Oxytocin in female voles

Released during mating, facilitating the formation of pair bonds by acting on specific brain regions.

Nucleus accumbens and prefrontal cortex

Brain areas involved in reward processing and social attachment, influenced by oxytocin.

Dopamine interaction with oxytocin

Reinforces the bond with the mate, promoting monogamous behavior.

Vasopressin in male voles

Regulates sexual behavior, territoriality, aggression, and pair bonding.

Vasopressin

A hormone that acts on the ventral pallidum and lateral septum, enhancing pair bonds and paternal behavior in monogamous species.

Prairie Voles

A monogamous species that exhibits higher levels of vasopressin receptors, enhancing pair bonding.

Testosterone

A hormone important for libido and sexual arousal, present in both men and women.

Estrogen

A hormone that plays a role in modulating sexual desire, particularly in women, fluctuating throughout the menstrual cycle.

Progesterone

A hormone that also modulates sexual desire, particularly in women.

Hypothalamus

A brain region involved in sexual motivation and behavior.

Amygdala

A brain region involved in sexual motivation and behavior.

Prefrontal Cortex

A brain region involved in sexual motivation and behavior.

Somatosensory Pathways

Crucial pathways for the perception of physical touch and sensations associated with sexual activity.

Sensory Receptors

Cells in the skin and genital areas that detect stimuli and send signals to the spinal cord and brain.

Somatosensory Cortex

Processes signals from sensory receptors, contributing to the experience of touch, pleasure, and arousal.

Sexually Dimorphic Nucleus (SDN)

A brain region in the hypothalamus associated with sexual orientation, influenced by prenatal hormone exposure.

Oxytocin

A neuropeptide known as the 'love hormone,' released during physical touch and sexual activity, promoting bonding and trust.

Nucleus Accumbens

A brain region that oxytocin acts on to enhance emotional connections.

Vasopressin and Male Bonding

Vasopressin influences territorial and protective behaviors, contributing to male bonding.

Pair Bonding in Voles

Oxytocin is involved in pair bonding, with infusion into the brain producing similar effects.

Sexual Orientation

A complex trait likely influenced by multiple brain regions and factors beyond the SDN.

Testicular Cancer and Testosterone

Men who have had both testes removed show little interest in sex unless given testosterone.

Menopause and Sexual Drive

Women after menopause may exhibit decreased sex drive, which can be restored with low levels of estrogen and testosterone.

Low Testosterone Replacement

Very little replacement testosterone is needed to restore interest in sex for boys and men with low testosterone.