![]() ![]() These results suggest that low doses of cortisol do not affect baro-afferent signals, but central or efferent components of the arterial baroreflex circuit presumably via rapid, non-genomic mechanisms. There was no effect of cortisol on the CMS effect, however. Furthermore, BRS increased in the cortisol group after cortisol infusion. In the cortisol group, salivary cortisol concentration increased after IV cortisol administration, indicating effective distribution of the substance throughout the body. Baroreflex sensitivity (BRS) of heart rate (HR) control was measured non-invasively based on spontaneous beat-to-beat HR and systolic blood pressure changes. CMS was assessed at four measurement points: baseline, -16 min, +0 min, and +16 min relative to substance application. The CMS procedure involved the assessment of eye blink responses to acoustic startle stimuli elicited at six different latencies to ECG-recorded R-waves (R +0, 100, 200, 300, 400 and 500 ms). ![]() Using a single blind, randomized controlled design, the cortisol group (n=16 volunteers) received 1 mg cortisol intravenously, while the control group (n=16) received a placebo substance. Cardiac modulation of startle (CMS) has been proposed as a method to reflect cardio-afferent signals at subcortical (potentially brainstem-) level. ![]() While peripheral effects have been excluded, it remains unclear whether this effect is mediated by cortical or subcortical (e.g. The recruitment of other cognitive processes during active decision-making, however, may facilitate GC modulation of mate choosiness, thereby promoting tactical plasticity at this critical life history juncture.Ĭortisol, the final product of human HPA axis activation, rapidly modulates the cortical processing of afferent signals originating from the cardiovascular system. These findings may reflect a buffering of primary sensory areas in the brain against elevated GCs. Further, we found no effect of elevated GCs on sexual proceptivity or the species-typical preference for longer calls. Females in the moderate dose group (60 ng g-1), however, exhibited a significant increase (>100%) in choosiness. In contrast, females in the vehicle, Low (20 ng g-1) and High (180 ng g-1) corticosterone groups exhibited a nominal decline in choosiness after injection, suggesting that the experience of injection has little or perhaps slightly suppressive effects on female choosiness. Females in the control group (no injection) showed no change in choosiness across timepoints. We found support for this predicted inverted-U relationship. We predicted that mate choosiness-forfeiting an initial mate preference to pursue a suddenly more attractive mate-would be particularly impacted by elevated GCs with moderate GC levels associated with greater choosiness. To our knowledge this is the first experimental study on the endocrine basis of mate choosiness. Here we investigated the effects of GC concentrations on three aspects of female sexual behavior in breeding Cope's gray treefrogs (Hyla chrysoscelis): proceptivity-a measure of sexual motivation, intraspecific mate preferences, and mate choosiness. Glucocorticoids (GCs) are rarely studied in the context of female mate choice, despite the expression of receptors for these products in sexual, sensory and decision-making brain areas. ![]()
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