Neuroanatomy and function of human sexual behavior: A neglected or unknown issue?

INTRODUCTION

Sexual desire, arousal, and orgasm are mediated by complex, yet still not fully understood, interactions of the somatic and autonomic nervous systems operating at the central and peripheral levels. Disruption of endocrine, neural, or vascular response, caused by aging, medical illness, neurological diseases, surgery, or drugs, can lead to sexual dysfunctions, thus significantly affecting patients' quality of life.

PURPOSE

This narrative review aims at characterizing the involvement of the central nervous system in human sexual behavior.

METHODS

A literature search was conducted using PubMed in its entirety up to June 2018, analyzing the studies dealing with the neurobiological and neurophysiological basis of human sexuality.

RESULTS

Sexual behavior is regulated by both subcortical structures, such as the hypothalamus, brainstem, and spinal cord, and several cortical brain areas acting as an orchestra to finely adjust this primitive, complex, and versatile behavior. At the central level, dopaminergic and serotonergic systems appear to play a significant role in various factors of sexual response, although adrenergic, cholinergic, and other neuropeptide transmitter systems may contribute as well.

CONCLUSIONS

Providing healthcare professionals with information concerning sexual behavior may overcome useless and sometimes dangerous barriers and improve patient management, since sexual well-being is considered one of the most important aspects of one's quality of life.

Approach to the male patient with sexual dysfunction

The management of the male patient with sexual dysfunction (SD) requires special knowledge and abilities. Generally, SD is best approached from the physiologic perspective, keeping in mind that sexual functioning has important psychosocial dimensions. The history obtained from the patient and, if possible, from his partner should seek information not only on the SD, but also on coexisting neurologic or medical disorders. A list of drugs should be obtained, as many prescription drugs, even in low doses, can influence sexual function. The clinical examination, including sensory, motor, and reflex testing of the lumbosacral segments, may reveal pertinent somatic abnormalities, which in the case of a suspected peripheral nervous system lesion may be supported by clinical neurophysiologic testing. The first-line diagnostic approach includes defining the type of sexual dysfunction to allow the most appropriate therapy. Metabolic and other systemic diseases need to be ruled out. Patients suspected of having psychologic, structural, urologic, endocrinologic, or vascular etiology of SD should be referred to the appropriate specialist.