Neural mediation of estrogen-dependent courtship behavior in female ring doves.

Investigated the role played by the preoptic-hypothalamic region in the mediation of female ring dove courtship behavior. In Exp I, 43 ovariectomized Ss were tested in response to estradiol benzoate (EB) injections both before and after preoptic area (POA), posterior medial hypothalamus (PMH), or sham lesions. Only the PMH group's behavior significantly declined following lesions. Exp II, with 46 Ss, examined whether intracranial EB implants would be effective in stimulating courtship behavior in ovariectomized Ss. Unilateral EB implants were placed throughout the hypothalamic region, including rostral to the anterior preoptic and caudal to the PMH. Implants in the PMH were most effective in stimulating behavior. Results indicate the importance of the PMH in mediation of estrogen-dependent courtship behavior and are analogous to recent findings concerning the role of the ventromedial hypothalamus in mammalian female sexual behavior. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estrogen facilitation of progesterone-induced incubation behavior in castrated male ring doves.

Previous studies have shown that incubation is shared by both male and female ring doves and is induced, without prior participation in courtship and nest building, by progesterone (100 mg/day) treatment. In the present experiment with 52 mature male ring doves, it was shown that the effectiveness of progesterone is markedly reduced by castration and restored after estradiol benzoate (200 mg/day * 14) pretreatment, thus simulating the endocrine events which precede incubation in the female. Estrogen also stimulated the appearance of nest cooing (another isomorphic behavior) but not bow cooing (a male-specific display). Results are discussed in terms of hormonal specificity underlying reproductive behavior and the possible physiological roles of estrogen and progesterone in the ring dove. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of gonadal hormones in incubation behavior of male ring doves (Streptopelia risoria).

Examined the role of testicular hormones in the incubation behavior of 85 male ring doves. Intramuscular injection of testosterone propionate (TP) at 100 mg/day to intact or castrated Ss throughout a reproductive cycle had no deleterious effects on sitting or crop-sac growth. Similarly, castrated Ss given TP only until the start of a reproductive cycle incubated normally. Thus, changes in androgen titer following courtship do not affect incubation behavior. In contrast, progesterone administered to intact Ss at 100 mg/day throughout a reproductive cycle interfered with both sitting behavior and crop-sac growth. It is concluded that high levels of progesterone (whether of gonadal or adrenal origin) would be incompatible with maintenance of incubation, possibly because of interference with prolactin secretion. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Role of adrenal hormones in incubation behavior of male ring doves (Streptopelia risoria).

Injected 111 male ring doves intramuscularly with dexamethasone throughout a reproductive cycle in an attempt to suppress adrenocortical secretions. Ss were tested for initiation and maintenance of incubation behavior. Treated Ss showed normal initiation of sitting when observed in their cages, but when they were tested alone in novel cages initiation of incubation tended to be disrupted. Prolonged dexamethasone treatment interfered with maintenance of incubation behavior in both test situations. The deleterious effect of dexamethasone on maintenance of home cage sitting was alleviated by concurrent treatment with prolactin or ACTH. In conclusion, adrenal secretions do not seem to be necessary for onset of incubation in males, but there are hormonal requirements for maintenance of this behavior. (35 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of posterior hypothalamic lesions on voluntary behavior and hippocampal electroencephalograms in the rat.

Postoperatively rated 126 male hooded rats with posterior hypothalamic lesions for somnolence. Ss were later subjected to formal testing. Ss showed deficits in initiating voluntary movements (walking, swimming) but more automatic movements seemed less impaired (grooming, scratching, tail rattling). Somnolent Ss swam in but could not escape cold water, but they could not swim in warm water. Initial somnolence was related to deficits in shock avoidance and the initiation of walking and swimming. Ss could learn a T maze to escape shock and an E maze to escape cold but not warm water. Hippocampal rhythmical slow activity frequency was reduced postoperatively; amplitude was normal. Results support the idea that the posterior hypothalamus is part of a trigger mechanism for the initiation and maintenance of voluntary movement. (44 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hormones and midbrain mediation of courtship behavior in the male ring dove (Streptopelia risoria).

Investigated the possible role of the intercollicularis (ICo) region in the androgen-dependent courtship behavior of male ring doves. In Exp I, bilateral lesions in the ICo region reduced nest-cooing but did not specifically alter other courtship behavior of males tested with stimulus females. In Exp II, unilateral implants containing crystalline testosterone propionate (TP) or cholesterol (C) were placed in the ICo region or in other parts of the midbrain of castrated Ss. The TP implants activatad nest-cooing only when placed in the ICo region. Diffusion from the implant was probably not responsible for the elicitation of nest-cooing, since the weights of the peripheral steroid-sensitive tissues of Ss implanted with TP and C did not differ and since many sites near, but not in, the ICo region were ineffective. Data demonstrate the importance of the ICo region in the expression of courtship behavior in the male ring dove. The facilitation of certain vocal courtship behavior by hormonal stimulation is in line with the suggestion that the central gray/ICo/torus semicircularis regions of the vertebrate brain are analogous in their mediation of vocalizations. (58 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of medial preoptic–anterior hypothalamic lesions on development of sociosexual behavior in dogs.

Bilateral medial preoptic–anterior hypothalamic lesions in adult male dogs eliminate or impair copulatory behavior and reduce urine-marking responses but do not affect aggressive behavior. The present study examined the emergence of the adult forms of these same male sociosexual behavioral patterns when the lesions were made prior to puberty. 18 beagle puppies were allowed to interact with male peers during development. Ss with lesions had reduced frequency of juvenile mounting and an almost total absence of male copulatory activity in adulthood. Urine-marking and aggressive behavior in the juvenile and adult periods were not affected by the lesions. Findings reveal a sparing of function with regard to urine-marking but not sexual behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of estrogen on behavior of ovariectomized ring doves (Streptopelia risoria).

Gave 30 ovariectomized and 6 intact female ring doves daily injections of 0, 5, 25, 50, or 100 mg of estradiol benzoate (EB) in .1 cc of sesame oil. Characteristic female behavior patterns in response to male courtship were abolished by 2-stage bilateral ovariectomy. Depending on the dose level, these behavior patterns recovered after systemic EB treatment. At a dosage of 50 mg, full recovery of female behavior patterns, with the exception of nest building, was observed. The order of recovery of the behavior patterns resembled the order of appearance in the normal breeding cycle, suggesting a causal relation between the level of estrogen and the normal display of specific behavior patterns. At a higher dose (100 mg), the oviduct weight was stimulated further while behavioral effect was suppressed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of ovariectomy on the reproductive behavior of female ring doves (Streptopelia risoria).

Studied the behavior of 12 adult male and 12 adult female ring doves during the breeding period. The stages of female mating responsiveness were defined by characteristic behavioral events (e.g., approaching, nest soliciting, nest crouching, and nest building). In Exp. I, 24 females had their left (functional) ovary completely or partially removed or received sham operations. Sinistrally ovariectomized Ss lost their characteristic behavior patterns in response to courting: Their behaviors were regressed to that of the nonresponsive stage, where sleeping, perching, and other self-directed activities are the dominant behavior patterns. The characteristic responsive behavior patterns were recovered in some Ss as the right rudimentary ovary regenerated. In Exp. II with 25 female Ss, a 2-stage bilateral ovariectomy entirely abolished any chance of behavioral recovery. Results verify the role of ovarian hormones in female reproductive behavior in ring doves. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Female sexual responses in male cats facilitated by olfactory bulbectomy and medial preoptic/anterior hypothalamic lesions.

Using 23 sexually active male cats, the authors performed bilateral lesions of the medial preoptic/anterior hypothalamic area and olfactory bulbectomies, with the order of operations balanced. In all Ss, male sexual behavior was virtually eliminated by the combined operations. Increased levels of female proceptive behavior were seen after either type of lesion alone, and combined operations resulted in increased levels of receptivity. Results support the concept that there exists, within the brains of male animals, the neural basis for the display of female as well as male sexual responses and that certain brain operations may potentiate the display of female responses. However, it does not appear that the reduction of male behavior is necessarily coupled with an increase in female behavior, since no correlation was seen between the degree of enhancement of female behavior and the decrement in male behavior. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social dynamics of group courtship behavior in male red-sided garter snakes (Thamnophis sirtalis parietalis).

Examined the social dynamics of the formation of mating balls (gatherings of males) during the mating period of red-sided garter snakes to determine whether the mating balls are formed simply because of a common attraction to the female or whether males are stimulated by the mating balls themselves. Nine test males and 9 stimulus females were used in tests, along with 55 other males, to measure the effect of other courting males. Results show that male Ss courted females more actively when other males were also courting the female than when they were alone with her, suggesting that the female is more attractive to the male when courted by other males. A positive correlation was observed between the number of additional males present and the amount of courtship activity shown by the test male toward the stimulus female. The extent to which the courtship activity of the test males was stimulated by the presence of additional courting males was not influenced by how actively the additional males courted. Results suggest that males are intrinsically stimulated by mating balls. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of rostral medial forebrain bundle and olfactory tubercle lesions upon sexual behavior of male rats.

Examined the effect on sexual behavior of 57 male Sprague-Dawley rats of reduced olfactory system input to the preoptic area and medial forebrain bundle (MFB). Bilateral electrolytic lesions in the MFB just caudal to the preoptic area virtually abolished mating behavior. Electrolytic lesions or sham lesions placed bilaterally in the olfactory tubercle produced decrements in the mating behavior. There was no evidence of gonadotropic dysfunction in any of the groups, nor were there significant differences in their mean body weights at sacrifice. (22 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Estrogen-progesterone regulation of nest-building and incubation behavior in ovariectomized ring doves (Streptopelia risoria).

Determined the role of ovarian hormones in the induction of nest-building (tucking) and incubation behavior in female doves by systemic injections of estrogen, or progesterone, or estrogen combined with progesterone, or oil in 40 reproductively experienced, ovariectomized Ss. Combined estrogen and progesterone treatment was the most effective hormone regimen for eliciting both behavior patterns in females and also facilitated these behaviors in their 40 untreated mates. Differences in role of the gonadal progesterone in male and female doves are discussed. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Female and male sexual responses in female cats with ventromedial hypothalamic lesions.

Following preoperative testing for receptivity, proceptivity, and male mating behavior, 27 female cats received either lesions in the anterior or posterior portion of the ventromedial hypothalamus (VMH) or sham lesions. Neither of the VMH lesion placements reduced proceptivity and receptivity scores. However, the female mating pattern was significantly altered in that although females in both lesion groups initially allowed a stud male to mount, they usually did not allow the male to intromit. As in rodents, the VMH in the cat appears to be an important neural area for the display of normal female sexual behavior. Low levels of male sexual behavior were seen in the 3 groups preoperatively, and no changes were observed in the levels of male behavior following lesion placement. Thus, because lesions that disrupted female behavior did not affect male sexual behavior, it appears that the neural areas controlling homotypical and heterotypical sexual behaviors are not necessarily neurally linked. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social behavior of rats with chronic prefrontal lesions.

Studied the social behavior of adult male Wistar albino rats in 6 experiments following medial frontal (n = 20) or orbital frontal (n = 14) lesions. 34 Ss served as controls. While both lesion groups showed transient increases in emotionality, only the Ss with orbital frontal lesions showed changes in social behavior. They were more aggressive in male-male aggression and shock-induced aggression but failed to differ from controls on tests of gregariousness, territorial aggression, and predatory aggression. Data may provide support for C. M. Leonard's (1969) suggestion that the orbital frontal cortex of rats and monkeys is homologous. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Roles of the vomeronasal and olfactory systems in courtship behavior of male garter snakes.

Studied whether male garter snakes required intact vomeronasal or olfactory systems to detect the pheromone that triggers the chin-pressing behavior of courtship. Male garter snakes with testosterone propionate pellets implanted sc were tested for courtship displays with estradiol-benzoate-treated females. Three groups of 10 males were formed from snakes exhibiting strong courtship responses. Bilateral olfactory nerve cuts were attempted on 1 group, vomeronasal nerve cuts on a 2nd, and control surgeries on a 3rd. All snakes in the olfactory nerve cut and control groups courted after surgery, and 3 snakes in each group copulated. More than half of the snakes in the olfactory nerve cut group had complete nerve cuts. Nine of the 10 snakes in the vomeronasal nerve cut group exhibited no courtship responses after surgery. The 1 snake in this group that courted was the only snake in which intact vomeronasal nerve fascicles were observed. Data indicate that male garter snakes without functional olfactory systems do court and mate normally, but that male garter snakes without functional vomeronasal systems exhibit no courtship responses. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interactions between visual and vocal courtship stimuli in the neuroendocrine response of female doves.

Tested the predictions of 4 models of additive interaction between auditory and visual courtship stimuli in inducing the reproductive development of female ring doves (Streptopelia risoria). Ss were exposed to a male's courtship vocalizations in combination with different visual stimuli. Some Ss saw a male that was courting them; others saw the male while he was courting another female; a 3rd group heard the male's vocalizations come from behind the image of a conspecific; 4th group heard the sounds coming from the side of the conspecific's image; a final group heard the male but could not see a conspecific. Although all Ss were stimulated by the male's vocalizations, the first group had a greater neuroendocrine response (measured by reproductive tract development) than any other group, and the last group was less stimulated than the others. The 2nd, 3rd, and 4th groups showed no significant differences among themselves. This suggests that traditional ethological sensory filtering models may not be adequate to explain the interaction between visual and vocal courtship stimuli in the reproductive development of female doves. Rather than being a passive recipient of male-generated stimuli, the female dove may require evidence that she is an active partner in courtship before responding to the male. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of morphiceptin in the medial preoptic area on male sexual behavior

Morphiceptin, a selective mu opioid agonist, injected into the medial preoptic area (MPOA), delayed the onset of copulation in male rats, but did not affect genital reflexes, sexual motivation or general motor activity. In a dose-dependent manner, morphiceptin (100 ng and 1000 ng) injected into the MPOA increased mount and intromission latencies. Similar injections of morphiceptin into the ventromedial hypothalamus had no effect on any parameter of copulation. The increase in copulatory latencies following the injection of the highest dose of morphiceptin was blocked by pretreatment with the opioid antagonist naloxone. In the X-maze task, morphiceptin had no effect on sexual motivation, as measured by the percentage of trials on which the male chose the female's chamber, but it increased the number of trials in which the subject did not select a chamber within 60 s and the latency to the female the first time he chose her chamber. Similar to the copulation task, the mount and intromission latencies were also increased in the X-maze, after the male reached the female. Morphiceptin in the MPOA had no effect on ex copula genital reflexes, tested in restrained supine males, or on motor activity, tested in a grid box. These results suggest that morphiceptin disrupts either the specific copulatory somatomotor pattern or a more general motivational component.