Hormones and Behavior最新文献

How an organism responds to risk depends on how that individual perceives such risk. Integrating cues from multiple sensory modalities allows individuals to extract information from their environment, and whether and how the brain and body respond differently to different sensory cues can help reveal mechanistic decision-making processes. Here, we assessed neural, hormonal, and behavioral responses to different sensory cues of predation risk in Trinidadian guppies (Poecilia reticulata). Adult guppies were assigned to one of four treatment groups: control, visual, olfactory, and both sensory cues combined from a natural predator, the pike cichlid (Crenicichla alta), for 2 h. We found no difference in glucocorticoid response to any cue. However, we found behavioral and neural activation responses to olfactory-only cues. In addition, we found a sex by treatment effect, where males showed greater changes in neural activation in brain regions associated with avoidance behavior, while females showed greater changes in neural activation in regions associated with social behavior and memory, mirroring sex by treatment differences in behavioral antipredator responses. Altogether, our results demonstrate that single and combinatory cues may influence risk-taking behavior differently based on sex, suggesting that perception and integration of cues can cascade into sex differences in behavior.

The influence of the neuropeptide arginine vasotocin (AVT) has been demonstrated across various species, on an ample range of behaviors, yet the results appear to be highly species-specific. In this study, we aimed to test how AVT influences both social and non-social behaviors in the common waxbill Estrilda astrild, a highly social estrildid finch. Through a within-subject design study, we experimentally manipulated AVT pathways through muscular injections of both an agonist and an antagonist of AVT at different dosages, and performed competition over food tests to assess behavioral changes. Our observations reveal a decrease in birds' movements with both low and high dosages of AVT. Additionally, the higher AVT dosage led to a significant decrease in birds' feeding, aggressive behavior, and allopreening. Conversely, the lower AVT dosage increased the duration of allopreening, which is a proxy for affiliation. The use of Manning Compound, a V1a antagonist, did not produce any changes in behavior, however, the absence of affinity studies for this compound in birds makes it difficult to interpret these results. It is plausible that in common waxbills, AVT V1b or V1a receptors may be involved in regulating movement, feeding, aggressive behavior, and allopreening, rather than V2 AVT receptors.

Gastrointestinal (GI) symptoms such as bloating, constipation, and nausea are common in the days before menstruation, experienced by as many as 73 % of menstruating individuals. Mood may influence the link between menstrual cycle and GI symptoms, with prior studies indicating that even among healthy controls, GI symptoms worsen premenstrually and are associated with worsening mood. Associations between GI symptoms and mood are poorly understood among those with premenstrual syndrome (PMS), a cluster of mood and/or physical symptoms that occur in the week before menses affecting roughly 20 % of menstruators. Our primary aim was to examine associations between GI symptoms and mood symptoms across the menstrual cycle, in those who do and do not report PMS using a menstrual tracking app. We hypothesized that GI symptoms would be reported more frequently in the luteal phase than follicular phase, and that frequency of GI symptoms would be positively associated with mood symptoms in those with PMS. We analyzed data from 33,628 menstrual cycles across 32,241 participants, including n = 27,897 controls (29,137 menstrual cycles) and n = 4344 PMS participants (4491 menstrual cycles). GI symptoms were reported significantly more frequently in the luteal phase than the follicular phase in both control and PMS groups (p < 0.001). Mood symptoms were significantly positively associated with GI symptoms in both groups, in both follicular and luteal phases (p < 0.001). Results suggest that premenstrual GI symptoms are a common issue, and additional work is needed to explore associations between mood and GI symptoms in the context of the menstrual cycle.

Time of day can alter memory performance in general. Its influence on memory recognition performance for faces, which is important for daily encounters with new persons or testimonies, has not been investigated yet. Importantly, high levels of the stress hormone cortisol impair memory recognition, in particular for emotional material. However, some studies also reported high cortisol levels to enhance memory recognition. Since cortisol levels in the morning are usually higher than in the evening, time of day might also influence recognition performance. In this pre-registered study with a two-day design, 51 healthy men encoded pictures of male and female faces with distinct emotional expressions on day one around noon. Memory for the faces was retrieved two days later at two consecutive testing times either in the morning (high and moderately increased endogenous cortisol levels) or in the evening (low endogenous cortisol levels). Additionally, alertness as well as salivary cortisol levels at the different timepoints was assessed. Cortisol levels were significantly higher in the morning compared to the evening group as expected, while both groups did not differ in alertness. Familiarity ratings for female stimuli were significantly better when participants were tested during moderately increased endogenous cortisol levels in the morning than during low endogenous cortisol levels in the evening, a pattern which was previously also observed for stressed versus non-stressed participants. In addition, cortisol levels during that time in the morning were positively correlated with the recollection of face stimuli in general. Thus, recognition memory performance may depend on the time of day and as well as on stimulus type, such as the difference of male and female faces. Most importantly, the results suggest that cortisol may be meaningful and worth investigating when studying the effects of time of day on memory performance. This research offers both, insights into daily encounters as well as legally relevant domains as for instance testimonies.

Female fertility signals are found across taxa, and the precision of such signals may be influenced by the relative strength of different sexual selection mechanisms. Among primates, more precise signals may be found in species with stronger direct male-male competition and indirect female mate choice, and less precise signals in species with stronger indirect male-male competition (e.g. sperm competition) and direct female mate choice. We tested this hypothesis in a wild population of Kinda baboons in Zambia, combining data on female signals with reproductive hormones (estrogen and progesterone metabolites) and intra- and inter-cycle fertility. We predicted that Kinda baboons will exhibit less precise fertility signals than other baboon species, as they experience weaker direct and stronger indirect male-male competition. The frequency of copulation calls and proceptive behavior did not vary with hormones or intra- or inter-cycle fertility in almost all models. Sexual swelling size was predicted by the ratio of estrogen to progesterone metabolites, and was largest in the fertile phase, but differences in size across days were small. Additionally, there was variability in the timing of ovulation relative to the day of sexual swelling detumescence across cycles and swelling size did not vary with inter-cycle fertility. Our results suggest that female Kinda baboon sexual swellings are less precise indicators of fertility compared to other baboon species, while signals in other modalities do not reflect variation in intra- and inter-cycle fertility. Female Kinda baboon sexual signals may have evolved as a strategy to reduce male monopolizability, allowing for more female control over reproduction by direct mate choice.

Telomere length (TL) is an important cellular marker of biological aging impacting the brain and heart. However, how it is related to the brain (e.g., cognitive function and neuroanatomic architecture), and how these relationships may vary by sex and reproductive status, is not well established. Here we assessed the association between leukocyte TL and memory circuitry regional brain volumes and memory performance in early midlife, in relation to sex and reproductive status. Participants (N = 198; 95 females, 103 males; ages 45–55) underwent structural MRI and neuropsychological assessments of verbal, associative, and working memory. Overall, shorter TL was associated with smaller white matter volume in the parahippocampal gyrus and dorsolateral prefrontal cortex. In males, shorter TL was associated with worse working memory performance and corresponding smaller white matter volumes in the parahippocampal gyrus, anterior cingulate cortex, and dorsolateral prefrontal cortex. In females, the impact of cellular aging was revealed over the menopausal transition. In postmenopausal females, shorter TL was associated with poor associative memory performance and smaller grey matter volume in the right hippocampus. In contrast, TL was not related to memory performance or grey and white matter volumes in any memory circuitry region in pre/perimenopausal females. Results demonstrated that shorter TL is associated with worse memory function and smaller volume in memory circuitry regions in early midlife, an association that differs by sex and reproductive status. Taken together, TL may serve as an early indicator of sex-dependent brain abnormalities in early midlife.