Ion G. Motofei

Neurophysiology of the ejaculatory process: developing perspectives.

Libido or sexual interest is a psychological construct intended to explain the likelihood or strength of a sexual response. At the neural level, libido represents a superior/complex projection that most probably involves integration of ‘motivation’ centres in the diencephalon (e.g. medial preoptic area; sexually differentiated nucleus) with sensory, cognitive, and decision-making centres in the cortex. In men, the presence of androgen, particularly testosterone, appears to be an important modulator of sexual desire, ‘priming’ (i.e. lowering the threshold for) neural responsiveness under specific contexts/conditions and to sexually relevant stimuli [4].

Preliminary study with bicalutamide in heterosexual and homosexual patients with prostate cancer: a possible implication of androgens in male homosexual arousal

Study Type – Symptom prevalence (case series) 
Level of Evidence 4

A dual physiological character for sexual function: the role of serotonergic receptors

Anatomically, sexual reflexes are mixed (somatic‐autonomic) circuits, represented by emission (sympathetic centre and somatic afferents), expulsion (parasympathetic centre and somatic efferents) and erection (parasympathetic centre and somatic afferents). Physiologically, ejaculation has a dual autonomic mediation, consisting of two distinct and opposite autonomic centres (emission and expulsion), both with a positive contribution to the respective function. Experimentally, serotonin (5HT) has two distinct, opposite and positive effects on sexual function, with 5HT‐1A agonists decreasing intravaginal ejaculatory latency and erection, and 5HT‐2C agonists increasing both erection and ejaculatory latency. In this review I assume that 5HT modulates sexual reflexes, establishing a functional connection between the involved somatic and autonomic structures. The 5HT‐1A receptors are assumed to make the connection between somatic pathways and sympathetic centres while the 5HT‐2C receptors could establish the connection between somatic pathways and parasympathetic centres. Further studies will develop the cerebral sexual duality, explaining the implication of psychological factors in sexual function and the role of sexuality in psychosocial behaviour.

A dual physiological character for sexual function: libido and sexual pheromones.

Human sexual response is a complex function involving many cerebral, spinal and peripheral aspects; the last are relatively known and benefit from good pharmacological control, as in the case of erectile dysfunction. Spinal cord sexual reflexes also have a good theoretical and experimental description. There is minimal understanding of the cerebral sexual processes (libido, sexual arousal, orgasm). The initial perspective was that the cerebral areas implied in sexuality exert descending stimulatory and inhibitory influences on spinal cord sexual centres/reflexes. This was a wrong supposition, which inhibited progress in this subject, with a considerable impact on a subject’s individual and social life. A new approach to sexual function arises from the idea that simple neurological structures can support only simple functions, while a more complex function requires correspondingly complex anatomical structures. For this reason the spinal cord would not be able to realise the integration of multiple (spinal and psychosensorial) stimuli into a unique and coherent ejaculation response. Consequently, all mechanisms implied in human sexuality would be cerebral processes, ejaculation reflexes ascending in evolution to the cerebral level. This new evolutionary concept was developed after 2001 in five distinct articles on the cerebral duality of sexual arousal, sexual hormones, ejaculation and serotonergic receptors. During this period other published results suggested a possible cerebral duality for sexual pheromones and libido in humans. All these dual physiological aspects are integrated in this review into one neurophysiological model, thus trying to further develop the new concepts of sexual function and perhaps relational behaviour. In conclusion, ejaculation is a dual cerebral process with arousal sensation (hormonally modulated) and libido perception (pheromonally modulated) as the afferent part. Two neurophysiological axes could exist in both men and women. In this assumption the mechanisms for libido and sexual arousal are not the only ones invoked, their correlations and implications are also suggested, perhaps critical aspects for further developments in the field.

A dual physiological character for cerebral mechanisms of sexuality and cognition: common somatic peripheral afferents

What’s known on the subject? and What does the study add?

A pilot study on the sexual side effects of finasteride as related to hand preference for men undergoing treatment of male pattern baldness

Whats known on the subject? and What does the study add?

Finasteride adverse effects in subjects with androgenic alopecia: A possible therapeutic approach according to the lateralization process of the brain

Abstract Nowadays, finasteride is a relatively frequently prescribed drug in the therapeutic management of male androgenic alopecia. The reported adverse effects are notable in some patients, consisting in signs and symptoms that are encountered both during finasteride administration and after treatment cessation. Clinical and imagistic data show that cognition and sexuality are two distinct but interrelated environmental functions, most probable due to lateralization process of the brain. Specific for our topic, relatively recent published studies found that frequency and severity of finasteride adverse effects could be interrelated with hand preference and sexual orientation of the respective subjects. This paper tries to explain/support this interrelation through a psychophysiologic approach, to suggest how this premise could be further proved in dermatological practice, and to highlight its relevance in respect to therapeutic approach of male androgenic alopecia. As a possible therapeutic application, subjects having preference for a certain sexual orientation and/or predisposition for a given dominant hand could be advised before finasteride administration, that present an increased risk/sensitivity to develop adverse effects. Finally, even if finasteride and post-finasteride symptoms overlap to a large extent they should be, however, viewed as distinct physiopathologic entities, which could require perhaps different therapeutic approaches.

The Ventral-Hypothalamic Input Route: A Common Neural Network for Abstract Cognition and Sexuality

Classically, external receptors of the body transmit information from the environment to the cerebral cortex via the thalamus. This review explains and argues that only concrete external information is transmitted from peripheral receptors to the cortex via a thalamic route, while abstract and sexual external information are actually transmitted from peripheral receptors to the cortex through a cognitive hypothalamic route. Sexual function typically implies participation of two distinct partners, ensuring reproduction in many species including humans. Human sexual response involves participation of multiple (environmental, biological, psychological) kinds of stimuli and processing, so the understanding of sexual control and response supposes integration between the classical physiological mechanisms with the more complex processes of our ‘mind’. Cognition and sexuality are two relational functions, which are dependent on concrete (colours, sounds, etc.) and/or abstract (gestures, facial expression, how you move, the way you say something seemingly trivial, etc.) environmental cues. Abstract cues are encoded independent of the specific object features of the stimuli, suggesting that such cues should be transmitted and interpreted within the brain through a system different than the classical thalamo‐cortical network that operates on concrete (material) information. Indeed, data show that the cerebral cortex is capable of interpreting two distinct (concrete and abstract) formats of information via distinct and non‐compatible brain areas. We expand upon this abstract‐concrete dichotomy of the brain, positing that the two distinct cortical networks should be uploaded with distinct information from the environment via two distinct informational input routes. These two routes would be represented by the two distinct routes of the ascending reticular activating system (ARAS), namely the classical/dorsal thalamic input route for concrete information and the ventral hypothalamic input route for abstract cognition and sexuality. Physiologically, the hypothalamic (dual‐autonomic) route of the ARAS that processes abstract and sexual information is incompatible with the thalamic (somatic) route of the ARAS that processes concrete information, such that the two distinct routes would be needed to support the mind processes (awareness, consciousness, sexuality) through their own informational inputs from the environment. Informationally, the concrete external data are differentiated from abstract and sexual external data, so that they should be transmitted to cortex through distinct input routes. Pathologically, the hardware and/or software impairments of the hypothalamic default‐mode network generate disturbed messages within the brain (related to information transmitted on this route), laying at the basis of mental and sexual disorders. The novel conceptualisations presented in the present paper help address issues surrounding the mind‐brain dichotomy and, in doing so, suggest new possible avenues for exploration in the treatment and interventions for cognitive and sexual problems.

Are Hand Preference and Sexual Orientation Possible Predicting Factors for Finasteride Adverse Effects in Male Androgenic Alopecia

Sexual side effects of finasteride seem to be redoubtable, being encountered not only during therapy but also after treatment cessation. Consequently, any possible clinical/paraclinical elements that might predict these adverse effects would be useful in the selection of a therapeutic strategy for male androgenic alopecia. Previous published studies show that some compounds that interfere with sexual hormones can decrease sexual activation and response, according to hand preference (as reported for finasteride and tamoxifen) and according to sexual orientation (as noted for bicalutamide). Our preliminary published data and the arguments presented here suggest that these two individual parameters might be used by dermatologists in the therapeutic approach of male androgenic alopecia, so as to alert specific subsets of men, prior to treatment, of the potential increased risk for developing adverse effects to finasteride.

A Pilot Study on Tamoxifen Sexual Side Effects and Hand Preference in Male Breast Cancer

Recent clinical and imaging studies suggest that sex hormones modulate sexuality according to a psychophysiologic process of lateralization of the brain, with androgens playing a greater role in sexual functioning of left hemibrain/right handedness and estrogens possibly for right hemibrain/left handedness. Based on this perspective, the current study attempted to specify the relationship between hand preference, estrogens, and sexual function in subjects with male breast cancer, taking into account the sexual side effects of tamoxifen as the agent for inhibiting estrogen action. Twenty-eight Romanian men—17 right-handed and 11 left-handed—undergoing treatment with tamoxifen for male breast cancer participated in this study. These men were assessed both prior to and during tamoxifen treatment using the International Index of Erectile Function, a standardized instrument used for the evaluation of various aspects of sexual functioning, including erectile function (EF), orgasmic function (OF), sexual desire (SD), and overall functioning (OF). A main effect for handedness was found on EF, OF, SD, and OS scales, with right-handed men showing higher functioning than left-handed men. Regarding interaction effects, the left-handed group of men showed greater decreased sexual functioning during tamoxifen (on three subscales: OF, SD, OS) compared to right-handed men. Further research should be conducted in order to support and refine this potential lateralized process of sexual neuromodulation within the brain.