Effects of antidepressant treatment on sexual arousal in depressed women: a preliminary FMRI study

Anatomical Markers of Activity in Hypothalamic Neurons

The scientific community has searched for years for ways of examining neuronal tissue to track neural activity with reliable anatomical markers for stimulated neuronal activity. Existing studies that focused on hypothalamic systems offer a few options but do not always compare approaches or validate them for dependence on cell firing, leaving the reader uncertain of the benefits and limitations of each method. Thus, in this article, potential markers will be presented and, where possible, placed into perspective in terms of when and how these methods pertain to hypothalamic function. An example of each approach is included. In reviewing the approaches, one is guided through how neurons work, the consequences of their stimulation, and then the potential markers that could be applied to hypothalamic systems are discussed. Approaches will use features of neuronal glucose utilization, water/oxygen movement, changes in neuron-glial interactions, receptor translocation, cytoskeletal changes, stimulus-synthesis coupling that includes expression of the heteronuclear or mature mRNA for transmitters or the enzymes that make them, and changes in transcription factors (immediate early gene products, precursor buildup, use of promoter-driven surrogate proteins, and induced expression of added transmitters. This article includes discussion of methodological limitations and the power of combining approaches to understand neuronal function. © 2020 American Physiological Society. Compr Physiol 10:549-575, 2020.

Brain Morphological Changes With Functional Deficit Associated With Sexual Arousal in Postmenopausal Women

INTRODUCTION

We have not known how menopause synchronously influences brain morphology and function associated with visually stimulated sexual arousal in postmenopausal women.

AIM

This study used a combination of functional magnetic resonance imaging and voxel-based morphometry to evaluate menopause-related brain morphological and functional changes in postmenopausal women.

METHODS

Nineteen premenopausal women and 19 postmenopausal women underwent functional and structural magnetic resonance imaging. Brain function activity was measured while the subjects viewed an erotic video clip.

MAIN OUTCOME MEASURES

A 2-sample t-test was used for cross-analysis of the 2 groups for comparison of gray matter volumes (corrected P < .05) and brain activation (uncorrected P < .01).

RESULTS

Our study revealed a relationship between sexual function and morphological changes in postmenopausal women. Compared with premenopausal women, the postmenopausal group showed significantly lower brain activations in the major parts of the limbic system and basal ganglia, including the parahippocampal gyrus, head of caudate nucleus, insula, putamen, hippocampus, hypothalamus, amygdala, and globus pallidus, which are involved in sexual behavior and emotional responses. In morphometric analyses, postmenopausal women showed significantly decreased gray matter volumes of the insula, putamen, parahippocampal gyrus, amygdala, and anterior cingulate gyrus, most of which were associated with decreased functional activity during visual sexual arousal in postmenopausal women. In addition, the premenopausal group alone showed a positive correlation between the activity of the insula and the level of estradiol (Pearson correlation r = 0.588; P = .008).

CONCLUSION

This study demonstrates an association between menopause-related brain function and morphological changes in postmenopausal women. This finding provides insight into the neural mechanisms associated with the sexual functional deficit in postmenopausal women. Baek H-S, Kim G-W, Sundaram T, et al. Brain Morphological Changes with Functional Deficit Associated with Sexual Arousal in Postmenopausal Women. Sex Med 2019;7:480-488.

Neural correlates of emotion processing comparing antidepressants and exogenous oxytocin in postpartum depressed women: An exploratory study

Despite common use of antidepressants to treat postpartum depression, little is known about the impact of antidepressant use on postpartum brain activity. Additionally, although oxytocin has been investigated as a potential treatment for postpartum depression, the interaction between antidepressants and exogenous oxytocin on brain activity is unknown. We explored postpartum depressed women's neural activation in areas identified as important to emotion and reward processing and potentially, antidepressant response: the amygdala, nucleus accumbens and ventral tegmental area. We conducted a secondary analysis of a functional imaging study of response to sexual, crying infant and smiling infant images in 23 postpartum depressed women with infants under six months (11 women taking antidepressants, 12 unmedicated). Participants were randomized to receive a single dose of oxytocin or placebo nasal spray. There was significantly higher amygdala activation to sexual stimuli than either neutral or infant-related stimuli among women taking antidepressants or receiving oxytocin nasal spray. Among unmedicated women receiving placebo, amygdala activation was similar across stimuli types. There were no significant effects of antidepressants nor oxytocin nasal spray on reward area processing (i.e., in the nucleus accumbens or ventral tegmental area). Among postpartum women who remain depressed, there may be significant interactions between the effects of antidepressant use and exogenous oxytocin on neural activity associated with processing emotional information. Observed effect sizes were moderate to large, strongly suggesting the need for further replication with a larger sample.

Amitriptyline and Sexual Function: A Systematic Review Updated for Sexual Health Practice

Amitriptyline is an old drug but is still prevalently used as the first-line treatment for a variety of common diseases. Surprisingly, knowledge of sexual risks with amitriptyline comes from only one clinical trial and several case reports from three decades ago. In the current study, a systematic review of the literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) related to amitriptyline and sexual dysfunction (SD) was performed. The frequency, gender-difference, types, disease-specificity and time course of SD, and the relationship between SD and nonsexual adversity were studied. A total of 14 publications, including 8 qualified randomized clinical trials, were eligible. The frequency of SD in overall, male and female patients was 5.7, 11.9 and 1.7%, respectively. SD was six-fold higher in men than women. The frequency of SD was 6.9% in depressive patients compared with 0.8% in non-depressive patients ( p = .008), and gradually decreased at 8 weeks after treatment ( p = .02). Amitriptyline impacted arousal and libido more than orgasm and ejaculation in male patients but mainly libido in female patients. SD was significantly correlated with insomnia linearly whereas somnolence and nausea dually. Therefore, amitriptyline-associated SD mainly occurs in depressive and male patients, disturbs each phase of the sexual response cycle in men but mainly libido in women, gradually decreases under long-term treatment, and can be predicted by the co-existence of insomnia, somnolence or nausea during treatment. Clinicians should caution and tailor the gender and disease vulnerability of amitriptyline in their practice.

Relationship between SSRI-induced sexual dysfunction and central serotonergic activity based on the loudness dependence of auditory evoked potentials

RATIONALE

It has been hypothesized that selective serotonin reuptake inhibitor (SSRI)-induced sexual dysfunction can occur more frequently in patients with higher central serotonergic activity, and that this higher serotonergic activity can induce inhibition of sexual desire, ejaculation, and orgasm. Thus, the aim of this study was to determine the relationship between SSRI-induced sexual dysfunction and increased serotonin.

METHOD

Event-related potentials for the loudness dependence of auditory evoked potentials (LDAEP) were measured in 46 patients at a single time point. The subjects' scores on the Hamilton Depression Rating Scale and Antidepressant Side-Effect Checklist were also determined by the investigators at the same time point. All patients had received SSRI monotherapy.

RESULTS

Overall, 37 % (17/46) of the patients experienced some form of SSRI-induced sexual dysfunction: lack of sexual desire, impotence, orgasm, and menstrual abnormality or mastalgia were experienced by 21.7, 8.3, 15.2, and 20.6 % of the patients, respectively. The subjects were thus divided into two groups-those with and without sexual dysfunction-and their data were compared. There was a tendency for the LDAEP to be lower in the group with sexual dysfunction (1.04 ± 0.77 μV) than the group without sexual dysfunction (1.45 ± 0.86 μV), although the difference was not statistically significant (p = 0.086). Furthermore, the distribution of the frequency of SSRI-induced sexual dysfunction differed marginally significantly between patients with low and high LDAEP, dichotomized according to the median LDAEP on the Cz electrode (χ (2) = 3.664, p = 0.056).

CONCLUSIONS

There was a relatively high frequency of SSRI-induced sexual dysfunction in patients with low LDAEP.

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.