CAN consists of a network of interconnected brain areas, such as the telencephalon, diencephalon, and brainstem, which control preganglionic sympathetic and parasympathetic visceromotor outputs. Here we focus on human emotional crying (including tear production) and draw upon findings specific to vocalizations where relevant. Further research will be needed to investigate more precisely the time course of crying and the role of specific physiological mechanisms in crying onset and subsequent changes and its relationship with emotion (regulation) and stress processes. Consequently, alterations in sympathetic vasoconstrictor nerve activity and the transduction of this activity into vasomotor tone have significant effects on the regulation of blood flow and arterial pressure. A further study could examine the effect of estradiol and progesterone on sound-induced vasoconstriction and its interaction with the effect of testosterone and cortisol by recruiting female participants and by examining the phase of their menstrual cycle on the day of the experiment. Given that the purpose of the study was to examine the effect of testosterone, cortisol, and the testosterone/cortisol ratio on sound-induced vasoconstriction, we wanted to exclude the possible effects of estradiol and progesterone. However, there was no direct evidence of the contribution of the noradrenergic sympathetic nerves to the sound-induced vasoconstriction because we could not directly measure the activity of neurons located within the RVLM. In the between-subject analysis, the finger BVPRs, cortisol levels, testosterone levels, and testosterone/cortisol ratios for three sound stimuli were averaged for each participant. To the best of our knowledge, only one single investigation specifically focused on human emotional crying and the brain . These pathways are responsible for conveying the felt aspects of emotional expressions, such as is typically involved in laughter and crying. In contrast, ablation of the overlying neocortex had only a transient effect on distress calls after separation, whereas crying produced in other contexts, such as feeding, physical restraint, and alarm, appeared to be unaffected. Further, the role of the amygdala in crying is clearly apparent in a study demonstrating that ablation of this structure in rhesus monkeys significantly decreased distress vocalizations. However, the current knowledge about the role of PAG in human crying is largely limited to vocal utterances (in animals and humans), although recent findings about pathological crying in humans, on which we elaborate next, seem to represent a reasonable argument for the importance of the PAG for the production of emotional tears as well. The SNS and testosterone are intricately linked, with each influencing the other in a complex interplay. Their interplay influences how individuals react to stressful situations and engage in risk-taking behaviors. While they can offer benefits, they can also have side effects and may not be suitable for everyone. However, it is important to note that the use of testosterone boosters should be approached with caution. Sertoli cells play a crucial role in testis formation and in the process of spermatogenesis. This process is continuous, in which diploid unipotent germ cells differentiate, and subsequently undergo the process of meiotic cell division, forming specialized haploid cells, the spermatozoa . Preganglionic fibers from both, the sympathetic and parasympathetic ANS, release the neurotransmitter acetylcholine. This system is divided into sympathetic and parasympathetic autonomous nervous system according to its anatomical, physiological and pharmacological characteristics 1, 2. This system can be functionally divided into sympathetic and parasympathetic autonomic nervous system 1, 2. The PNS includes 12 cranial nerves, with 10 nerves originating from the brainstem and 31 spinal nerves pairs coming from the spinal cord 1, 2. Banks et al. observed some differences between the action of neurotransmitters noradrenaline and acetylcholine in a study demonstrating the role of neurotransmitters in different species (human, rat, rabbit and mouse) on the smooth muscle cells contraction of tunica albuginea. Later, Lamano-Carvalho et al. following the same line, demonstrated that, after chemical sympathectomy, prepubertal animals presented an increase in the concentration of progesterone and a decrease in androstenedione and testosterone levels. Although it is known that both sympathetic and parasympathetic fibers innervate the testes, few studies demonstrate the role of cholinergic innervation in this gonad. However, Sosa et al. demonstrated that when stimulating the inferior spermatic nerve, via noradrenaline, there was an increase in the concentration of testosterone in the testes. Autonomous innervation via the superior spermatic nerve is related to the expression of LH (luteinizing hormone) receptors in Leydig cells of immature rats, ensuring the testicular development of these animals . The production of distress vocalizations is a complex process, which includes laryngeal activity, respiratory movements, and supralaryngeal (articulatory) activity. Finally, we summarize what is now known about the neurobiology of human emotional crying, what remains unknown, and important directions for future research. The animal work additionally provided some relevant information on the neural underpinnings of specific emotional states that are related to crying. However, we also acknowledge that the production of emotional tears (and some related specific facial expression characteristics of human tearful crying) may have different functional characteristics and neurobiological underpinnings in humans. Parvizi et al. and Rabins and Arciniegas ; specifically discuss the role of the cerebellum in pathological crying and laughing. In neurology, these conditions are well-known as pathological crying, or pseudobulbar affect 44–47. Another important source of knowledge concern clinical observations in neurological patients with damage in specific brain structures, who display pathological crying (and laughing). Some of these findings may reflect a decrease in subjective distress, as fMRI findings in humans demonstrate that the amygdala and ACC are strongly activated during self-induced sadness (e.g., 42,43).
