A Markerless 3D Computerized Motion Capture System Incorporating a Skeleton Model for Monkeys

In this study, we propose a novel markerless motion capture system (MCS) for monkeys, in which 3D surface images of monkeys were reconstructed by integrating data from four depth cameras, and a skeleton model of the monkey was fitted onto 3D images of monkeys in each frame of the video. To validate the MCS, first, estimated 3D positions of body parts were compared between the 3D MCS-assisted estimation and manual estimation based on visual inspection when a monkey performed a shuttling behavior in which it had to avoid obstacles in various positions. The mean estimation error of the positions of body parts (3–14 cm) and of head rotation (35–43°) between the 3D MCS-assisted and manual estimation were comparable to the errors between two different experimenters performing manual estimation. Furthermore, the MCS could identify specific monkey actions, and there was no false positive nor false negative detection of actions compared with those in manual estimation. Second, to check the reproducibility of MCS-assisted estimation, the same analyses of the above experiments were repeated by a different user. The estimation errors of positions of most body parts between the two experimenters were significantly smaller in the MCS-assisted estimation than in the manual estimation. Third, effects of methamphetamine (MAP) administration on the spontaneous behaviors of four monkeys were analyzed using the MCS. MAP significantly increased head movements, tended to decrease locomotion speed, and had no significant effect on total path length. The results were comparable to previous human clinical data. Furthermore, estimated data following MAP injection (total path length, walking speed, and speed of head rotation) correlated significantly between the two experimenters in the MCS-assisted estimation (r = 0.863 to 0.999). The results suggest that the presented MCS in monkeys is useful in investigating neural mechanisms underlying various psychiatric disorders and developing pharmacological interventions.     

Female-female mounting among goats stimulates sexual performance in males

The hypothesis that female-female mounting is proceptivity in goats, in that male goats are aroused by the visual cues of this mounting behavior, was tested. Once a week, male goats were randomly selected and placed in a test pen in which they were allowed to observe one of six selected social or sexual stimulus conditions. The stimulus conditions were one familiar male with two estrous females (MEE); three estrous females that displayed female-female mounting (E(m)); three estrous females that did not mount (E(nm)); three non-estrous females (N(E)); three familiar males (M); and no animals in the pen (Empty). After 10 min, the stimulus animals were removed, and an estrous female was placed in the test pen with the male for a 20-min sexual performance test. During sexual performance tests, the frequencies and latencies of all sexual behaviors were recorded. This procedure was repeated so all males (n = 6) were tested once each test day, and all the stimulus conditions were presented each test day. This was repeated weekly until all males had been exposed to each stimulus condition. Viewing mounting behavior, whether male-female or female-female, increased the total number of sexual behaviors displayed, increased ejaculation frequency, and decreased latency to first mount and ejaculation, post-ejaculatory interval, and the interval between ejaculations. We conclude that male goats are aroused by the visual cues of mounting behavior, and that female-female mounting is proceptivity in goats.     

Baboon (Papio anubis) social complexity--a network approach

Although many studies have analyzed the causes and consequences of social relationships, few studies have explicitly assessed how measures of social relationships are affected by the choice of behaviors used to quantify them. The use of many behaviors to measure social relationships in primates has long been advocated, but it was analytically difficult to implement this framework into primatological work. However, recent advances in social network analysis (SNA) now allow the comparison of multiple networks created from different behaviors. Here we use our database of baboon social behavior (Papio anubis, Gashaka Gumti National Park, Nigeria) to investigate (i) to what extent social networks created from different behaviors overlap, (ii) to what extent individuals occupy similar social positions in these networks and (iii) how sex affects social network position in this population of baboons. We used data on grooming, aggression, displacement, mounting and presenting, which were collected over a 15-month period. We calculated network parameters separately for each behavior. Networks based on displacement, mounting and presenting were very similar to each other, whereas grooming and aggression networks differed both from each other and from mounting, displacement and presenting networks. Overall, individual network positions were strongly affected by sex. Individuals central in one network tended to be central in most other networks as well, whereas other measures such as clustering coefficient were found to vary depending on the behavior analyzed. Thus, our results suggest that a baboon's social environment is best described by a multiplex network based on affiliative, aggressive and sexual behavior. Modern SNA provides a number of useful tools that will help us to better understand animals' social environment. We also discuss potential caveats related to their use.     

Recording movement traces in field studies

A method is presented for the simultaneous recording of body movements in space and electrophysiological data in field studies in order to obtain criteria for the evaluation of muscular and mental effort, with the aim of improving the design of workplaces--here exemplified the driver's cab of a railway engine. Eight light-emitting diodes were attached to certain parts of the body and their positions recorded by means of a video system. The positions of the diodes were computed off-line with the aid of image-processing system. In comparison with the resolution of the video camera the accuracy of determining the coordinates of a diode can clearly be improved by computing the center of its imaged bright area. In combination with recordings of the eye movements and the railway track by means of an extra video camera, evaluation of the movement traces permits a differentiated study of specific movements and actions.     

Long-term Behavioral Tracking of Freely Swimming Weakly Electric Fish

Long-term behavioral tracking can capture and quantify natural animal behaviors, including those occurring infrequently. Behaviors such as exploration and social interactions can be best studied by observing unrestrained, freely behaving animals. Weakly electric fish (WEF) display readily observable exploratory and social behaviors by emitting electric organ discharge (EOD). Here, we describe three effective techniques to synchronously measure the EOD, body position, and posture of a free-swimming WEF for an extended period of time. First, we describe the construction of an experimental tank inside of an isolation chamber designed to block external sources of sensory stimuli such as light, sound, and vibration. The aquarium was partitioned to accommodate four test specimens, and automated gates remotely control the animals'' access to the central arena. Second, we describe a precise and reliable real-time EOD timing measurement method from freely swimming WEF. Signal distortions caused by the animal''s body movements are corrected by spatial averaging and temporal processing stages. Third, we describe an underwater near-infrared imaging setup to observe unperturbed nocturnal animal behaviors. Infrared light pulses were used to synchronize the timing between the video and the physiological signal over a long recording duration. Our automated tracking software measures the animal''s body position and posture reliably in an aquatic scene. In combination, these techniques enable long term observation of spontaneous behavior of freely swimming weakly electric fish in a reliable and precise manner. We believe our method can be similarly applied to the study of other aquatic animals by relating their physiological signals with exploratory or social behaviors.     

Role of Endocannabinoids and Cannabinoid-1 Receptors in Cerebrocortical Blood Flow Regulation

Background

Endocannabinoids are among the most intensively studied lipid mediators of cardiovascular functions. In the present study the effects of decreased and increased activity of the endocannabinoid system (achieved by cannabinoid-1 (CB1) receptor blockade and inhibition of cannabinoid reuptake, respectively) on the systemic and cerebral circulation were analyzed under steady-state physiological conditions and during hypoxia and hypercapnia (H/H).

Methodology/Principal Findings

In anesthetized spontaneously ventilating rats the CB1-receptor antagonist/inverse agonist AM-251 (10 mg/kg, i.v.) failed to influence blood pressure (BP), cerebrocortical blood flow (CoBF, measured by laser-Doppler flowmetry) or arterial blood gas levels. In contrast, the putative cannabinoid reuptake inhibitor AM-404 (10 mg/kg, i.v.) induced triphasic responses, some of which could be blocked by AM-251. Hypertension during phase I was resistant to AM-251, whereas the concomitant CoBF-increase was attenuated. In contrast, hypotension during phase III was sensitive to AM-251, whereas the concomitant CoBF-decrease was not. Therefore, CoBF autoregulation appeared to shift towards higher BP levels after CB1-blockade. During phase II H/H developed due to respiratory depression, which could be inhibited by AM-251. Interestingly, however, the concomitant rise in CoBF remained unchanged after AM-251, indicating that CB1-blockade potentially enhanced the reactivity of the CoBF to H/H. In accordance with this hypothesis, AM-251 induced a significant enhancement of the CoBF responses during controlled stepwise H/H.

Conclusion/Significance

Under resting physiological conditions CB1-receptor mediated mechanisms appear to have limited influence on systemic or cerebral circulation. Enhancement of endocannabinoid levels, however, induces transient CB1-independent hypertension and sustained CB1-mediated hypotension. Furthermore, enhanced endocannabinoid activity results in respiratory depression in a CB1-dependent manner. Finally, our data indicate for the first time the involvement of the endocannabinoid system and CB1-receptors in the regulation of the cerebral circulation during H/H and also raise the possibility of their contribution to the autoregulation of CoBF.     

短尾猴的社会行为与社会关系

群体生活的动物通过社会行为相联系,社会行为的类别和发生的频率决定了动物社会关系的性质,进而决定了社会结构的类型。本文根据作者在安徽黄山对短尾猴16年的观察研究,描述和分析了一些重要的社会行为,探讨了短尾猴社会中各种社会关系的特点和性质。雌性短尾猴之间的行为比较简单,缺乏多样性,主要通过近距及理毛等状态性行为建立和维持,是长久和稳固的关系;雄性短尾猴之间具有丰富的行为,事件性行为(如拥抱、爬跨等)占主要部分,易发生冲突但也易于和解;雄性和雌性关系与繁殖季节有关,交配期主要是性关系,产仔期主要是友好关系;成体和幼体的关系主要是照料与被照料的关系。     

Cyclic proceptivity in a captive female orang-utan (Pongo Pygmaeus Abelii)

An adult male—female pair of orang-utans was observed for a 3-month period, commencing with the introduction of the animals to each other. After approximately 2 weeks, the female began to show proceptive behaviors towards the male. Two other proceptive periods were observed, occuring from 26 to 30 days apart, and lasting for 4–6 days. These female-initiated periods of sexual activity began with increased locomotor activity, solitary play, proximity to the male, following the male, and social grooming. The peak periods of proceptive behaviour included hand—genital contact, mouth—genital contact, rolling the male onto his back, both dorso-ventral and ventro-ventral mounting, and pelvic thrusting. Although hormonal levels could not be assessed in this study, it is believed that these peaks coincided with ovulation. In previous reports, the presence of proceptive behaviors was perhaps over-shadowed by highly aggressive sexual behavior on the part of male orang-utans. The visibility of proceptivity in this study is attributed to the large cage which allowed the female to escape the male's advances, enabled distance between the animals when they preferred it, and continuous exposure of the orangs to each other. This female orang-utan behavior was compared to the female sexual behaviours of the other great ape species — the chimpanzee and the gorilla.     

Size-assortative mating and sexual size dimorphism are predictable from simple mechanics of mate-grasping behavior

Background  

A major challenge in evolutionary biology is to understand the typically complex interactions between diverse counter-balancing factors of Darwinian selection for size assortative mating and sexual size dimorphism. It appears that rarely a simple mechanism could provide a major explanation of these phenomena. Mechanics of behaviors can predict animal morphology, such like adaptations to locomotion in animals from various of taxa, but its potential to predict size-assortative mating and its evolutionary consequences has been less explored. Mate-grasping by males, using specialized adaptive morphologies of their forelegs, midlegs or even antennae wrapped around female body at specific locations, is a general mating strategy of many animals, but the contribution of the mechanics of this wide-spread behavior to the evolution of mating behavior and sexual size dimorphism has been largely ignored.     

Sexual Experience Enhances Drosophila melanogaster Male Mating Behavior and Success

Competition for mates is a wide-spread phenomenon affecting individual reproductive success. The ability of animals to adjust their behaviors in response to changing social environment is important and well documented. Drosophila melanogaster males compete with one another for matings with females and modify their reproductive behaviors based on prior social interactions. However, it remains to be determined how male social experience that culminates in mating with a female impacts subsequent male reproductive behaviors and mating success. Here we show that sexual experience enhances future mating success. Previously mated D. melanogaster males adjust their courtship behaviors and out-compete sexually inexperienced males for copulations. Interestingly, courtship experience alone is not sufficient in providing this competitive advantage, indicating that copulation plays a role in reinforcing this social learning. We also show that females use their sense of hearing to preferentially mate with experienced males when given a choice. Our results demonstrate the ability of previously mated males to learn from their positive sexual experiences and adjust their behaviors to gain a mating advantage. These experienced-based changes in behavior reveal strategies that animals likely use to increase their fecundity in natural competitive environments.     

Hyperprolactinemia preferentially inhibits erectile function in adrenalectomized male rats

To determine if the inhibitory effects of hyperprolactinemia on sexual arousal and serum LH levels could be dissociated from those on erectile function, copulatory behavior was examined in pituitary-grafted, adrenalectomized male rats that had been castrated and given 20mm subcutaneous testosterone implants. Whereas transplantation of three pituitaries under the kidney capsules inhibited mounting rates in intact animals, pituitary grafting did not significantly reduce mounting rates in the adrenalectomized group beyond the effect of adrenalectomy alone. In contrast, the effects of pituitary grafting on erectile function were enhanced in the adrenalectomized animals. Hyperprolactinemia also caused a significant reduction in serum LH, but only in the intact animals. These results suggest that: 1. the effects of hyperprolactinemia on erectile function occur independently from those on sexual arousal, and 2. the inhibitory effects of hyperprolactinemia on sexual arousal are linked to the effects of hyperprolactinemia on LH release.     

Revisiting the same-sex mounting in chelonians under the concept of whole-animal

Most vertebrate species are bisexual. But as well as the sexual behavior, same-sex mating-like behavior sometimes occurs. Recently, the same-sex mounting reported from chelonians was reviewed. The potential causes for such behavior that were hypothesized, such as dearth of correct mates or expression of dominance, are of the social domain. On further consideration, it may be instructive to view animals more holistically. We propose here two additional hypothetical causes: intersex gonads, on which we present new data, and misleading body size, on which we speculate from recent literature. We also revisit the effect of the sex ratio on the frequency of same-sex mounting.     

The effect of season on the induction of sexual behavior by estradiol in female rhesus monkeys

Rhesus monkeys housed in an outdoor environment are seasonal breeders, with ovulations and concomitant sexual behavior limited to the fall and winter months. To determine if there is a seasonal difference in the capacity of physiological levels of estradiol (E2) to induce sexual behavior in ovariectomized rhesus monkeys housed outdoors, subjects living in a social group were treated with subcutaneous E2 implants in a counter-balanced design during the nonbreeding season (May-July) and during the breeding season (September-November). Serum E2 levels were monitored by obtaining blood samples twice a week. Three levels of E2 were studied: baseline (less than 30 pg/ml), follicular (100 pg/ml), and periovulatory (200 pg/ml). Two of five adult males in the group were injected with human chorionic gonadotropin (hCG) twice a week to insure that males with high testosterone levels were present during each season. Focal observations of behavior of 15 minutes' duration on each subject were conducted 5 days per week, with frequencies and durations of social, sexual, and solitary behaviors recorded. Concomitant 2-h group scans were made to record all occurrences of mounting behavior. Neither heterosexual serial mounting nor seminal plugs were ever observed in E2-treated females during the summer months. In contrast, copulation and seminal plugs were observed in subjects at both treatment levels during the fall. While E2-treated females engaged in homosexual mounting behavior during both summer and fall, E2 treatment resulted in heterosexual copulation only during the fall. Changes in patterns of social behavior paralleled changes in sexual behavior and were significantly affected by treatment and season, with more male-female interactions during the fall months.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of Microdesmis keayana roots on sexual behavior of male rats

In the present study, the aphrodisiac properties of Microdesmis keayana J. Léonard root extract and major isolated alkaloids were evaluated by observing the sexual behavior of male rats.Aqueous extract (150 mg/kg body weight) and pure alkaloids (3 mg/kg body weight) were administered orally by gavage to male rats. Latent times of observation, intromission and ejaculation, mounting behavior, number of intromissions and mating performances were evaluated and compared to those obtained with untreated rats in the presence of receptive and non-receptive females. The results have shown that aqueous extract and alkaloids of M. keayana stimulate sexual parameters in rats’ sexual behavior.A short-term toxicity study undertaken to establish the therapeutic index of aqueous extract, showed that a high dose of the extract (2 g/kg body weight) caused no mortality or changes in rats’ behavior.     

Facilitation of mounting behavior in male rats by intracranial injections of luteinizing hormone-releasing hormone

Luteinizing hormone-releasing hormone (LH-RH) administration has been reported to facilitate male sex behavior. This laboratory has previously reported development of the ‘mounting test’, a paradigm which reflects sexual arousal mechanisms. We have used this test to study the interaction of LH-RH with the central components of male copulatory behavior in the rat.Sixty 90-day-old Long-Evans male rats were screened for sex behavior and divided into 5 treatment groups. For all mounting tests, a local anesthetic was applied to the penis and mounts were scored during a 15-min exposure to a stimulus female. The animals were given 3 successive weekly tests. By the final test, a significant decrement in mounting behavior was noted, and those males given 50 ng LH-RH i.c.v. displayed more mounting in this test than animals given either no treatment or saline ($\text{P < 0.01}$). A slight but significant ($\text{P < 0.05}$) enhancement of performance was also noted in peptide-treated rats in test I. There was no significant difference in any of the tests between animals given lateral cerebroventricular (i.c.v.) injections of 2 μl acidified saline and those given no treatment. When blood samples were taken from similarly treated animals and assayed by radioimmunoassay for luteinizing hormone and testosterone, plasma levels of these hormones were not different at either 30 min or 2 h after injection of saline or LH-RH.Thus, in animals with diminished genital sensory input, LH-RH administration increases mounting behavior without inducing measurable reproductive endocrine changes. It is proposed that this effect results from an interaction of this peptide with the neural substrates of the arousal mechanism.     

How does Behavior Change the Brain? Multiple Methods to Answer Old Questions

Clearly the brain controls behavior but can behavior also "control" the brain? On an evolutionary time scale, selective ecological pressures shape the sensory and motor capacities as well as the body and behavior. Correspondingly, in development, behavior acts in concert with the environment to cause structural changes in the brain lasting a lifetime. Surprisingly, in "real time" social behavior can also cause changes, typically reversible, in the brain in adult animals. Changes caused by behavioral interactions can be dramatic, and in many instances, these interactions are directly related to reproductive behavior. Understanding how behavior sculpts the brain in the course of behavioral interactions is a major challenge. Analyzing such changes requires a model system allowing control of the biological and behavioral environment of many animals simultaneously yet allowing access to physiological, cellular and molecular processes being regulated. The mouthbrooding cichlid Haplochromis (Astatotilapia) burtoni (Günther) from Lake Tanganyika lends itself to the study of social influences on the brain. It has complex, though easily observable individual and social behaviors regulated by two distinct classes of males, those with territories and those without. Many features of the animals are shaped by social encounters including the maturation of juveniles, the hypothalamic-pituitary-gonadal axis, the growth rate, the basal stress level among others. How does social information effect change in the brain and body? Animals must attend to the social scene to identify their chances. Learning how social information is transduced into cellular changes in this species should help understand how this happens in other social animals.     

Involvement of CB1-receptors and beta-adrenoceptors in the regional hemodynamic responses to lipopolysaccharide infusion in conscious rats

A possible involvement of endocannabinoids in a chronic model of endotoxemia was assessed by measuring the regional (renal, mesenteric, hindquarters) hemodynamic responses to continuous 24-h LPS infusion (150 microg.kg(-1).h(-1)) in conscious, male Sprague-Dawley rats, in the absence or presence of the cannabinoid (CB1) receptor antagonist AM-251 (3 mg/kg). AM-251 inhibited the tachycardic and hindquarters vasodilator effects of LPS, but did not influence the other hemodynamic changes. In subsequent experiments, it was shown that the tachycardic and hindquarters vasodilator effects of LPS were also inhibited by the nonselective beta-adrenoceptor antagonist propranolol. In addition, the late (at 24 h) hindquarters vasodilator effects of LPS were inhibited by the beta2-adrenoceptor antagonist ICI-118551. Against the background of our previous work showing beta-adrenoceptor involvement in the cardiovascular effects of exogenous cannabinoids, we conclude that AM-251 may have been inhibiting endocannabinoid-modulated, sympathoadrenal-mediated activation of vasodilator beta-adrenoceptors in LPS-infused rats rather than suppressing a direct vasodilator action of endocannabinoids.     

CB1 receptor signaling regulates social anxiety and memory

The endocannabinoid (eCB) system regulates emotion, stress, memory and cognition through the cannabinoid type 1 (CB₁) receptor. To test the role of CB₁ signaling in social anxiety and memory, we utilized a genetic knockout (KO) and a pharmacological approach. Specifically, we assessed the effects of a constitutive KO of CB₁ receptors (CB₁KOs) and systemic administration of a CB₁ antagonist (AM251; 5 mg/kg) on social anxiety in a social investigation paradigm and social memory in a social discrimination test. Results showed that when compared with wild‐type (WT) and vehicle‐treated animals, CB₁KOs and WT animals that received an acute dose of AM251 displayed anxiety‐like behaviors toward a novel male conspecific. When compared with WT animals, KOs showed both active and passive defensive coping behaviors, i.e. elevated avoidance, freezing and risk‐assessment behaviors, all consistent with an anxiety‐like profile. Animals that received acute doses of AM251 also showed an anxiety‐like profile when compared with vehicle‐treated animals, yet did not show an active coping strategy, i.e. changes in risk‐assessment behaviors. In the social discrimination test, CB₁KOs and animals that received the CB₁ antagonist showed enhanced levels of social memory relative to their respective controls. These results clearly implicate CB₁ receptors in the regulation of social anxiety, memory and arousal. The elevated arousal/anxiety resulting from either total CB₁ deletion or an acute CB₁ blockade may promote enhanced social discrimination/memory. These findings may emphasize the role of the eCB system in anxiety and memory to affect social behavior .