Physiological Correlates of Aggression and Impulsivity in Free-Ranging Female Primates (original) (raw)
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Hormones and Behavior, 2022
A variety of studies show that the s-allele of the serotonin transporter genotype (5-HTT) is related to aggression. However, influences of sex and 5-HTT genotype of both subject and opponent have not received as much attention in aggression research. Using a nonhuman primate model, the present study explores differences in rates of aggression exhibited by 201 group-housed male and female rhesus monkeys (Macaca mulatta; 122 females; 79 males) exposed to an unfamiliar ageand sex-matched stranger while in the presence of other same-sex members of their social group. The study also assesses whether the rates of aggression increase when the home-cage resident, the unfamiliar stimulus animal, or both possess the short (s) allele of the 5-HTT. Results showed that, when compared to females, males exhibited higher rates of physical aggression toward the stranger, and when both the male resident and the male stranger possessed the s-allele, rates of physical aggression toward the stranger increased five-fold. Resident females also engaged *
Aggression and brain serotonergic responsivity: Response to slides in male macaques
Physiology & Behavior, 1995
Aggression and brain serotonergic responsivity: Response to slides in male macaques. PHYSIOL BEHAV 57(2) 205-208, 1995.--The association between central serotonergic responsivity (measured by prolactin response to acute administration of fenfluramine hydrochloride) and aggressivity was examined in 40 adult male cynomolgus monkeys (Macaca fascicularis). Prolactin response to fenfluramine was distributed bimodally with 24 monkeys displaying a "low" prolactin response and 15 showing a "high" prolactin response to the fenfluramine challenge. Behavioral responsivity was assessed by placing the monkeys individually in an open-field enclosure and presenting a series of photographic slides depicting both threatening and nonthreatening images. Monkeys that were low prolactin responders displayed significantly more aggressive gestures in response to a threatening slide of a human being than did the high responders (p < 0.05). Insofar as fenfluramine-stimulated prolactin release assesses serotonergic responsivity, these data support related findings in people and nonhuman primates linking reduced serotonergic activity and aggression.
Serotonergic influences on life-history outcomes in free-ranging male rhesus macaques
American Journal of Primatology, 2007
longitudinal measures of serotonergic and dopaminergic functioning are predictive of major life-history outcomes in nonhuman primate males. Low concentrations of CSF 5-HIAA are associated with negative life-history patterns characterized by social instability and excessive aggression, and positive life-history patterns characterized by higher dominance rank. Am. J. Primatol. 69:851-865, 2007.
Factors affecting aggression among females in captive groups of rhesus macaques (Macaca mulatta)
American Journal of Primatology, 2011
Captive groups of primates often exhibit higher rates of aggression than wild, free-ranging groups. It is important to determine which factors influence aggression in captivity because aggression, particularly intense aggression, can be harmful to animal health and well-being. In this study, we investigated the effect of ground substrate as well as season, rank, age, and group size on rates of agonistic interactions per female in seven captive groups of rhesus macaques (n 5 70 females, 1,723 focal samples) at the California National Primate Research Center. Agonistic interactions were divided into three categories: displacements, mild aggression, and intense aggression. Females living in enclosures with gravel substrate were 1.7 times more likely to be involved in intense aggression (e.g. chases and physical contact) than females living in enclosures with grass (Poisson regression model: Po0.001). Highranking females were at least 1.3 times more likely to be involved in mild (e.g. threats and lunges) aggression than lower-ranking females (low rank: P 5 0.03; mid rank: P 5 0.001). Females of all ranks were 1.5-1.9 times more likely to be involved in both intense and mild aggression during the breeding season than other seasons. Age and group size did not affect rates of mild or intense aggression. These findings indicate that although some aggression appears to be natural and unavoidable, i.e. aggression during the breeding season, the well-being of captive macaques can be improved by developing grass substrate in outdoor enclosures. Am.
Psychoneuroendocrinology, 2004
Individually housed rhesus monkeys sometimes spontaneously develop self-injurious behavior (SIB) in the form of self-directed biting that, on occasion, results in severe tissue damage and mutilation. We previously demonstrated lower levels of plasma cortisol in rhesus monkeys with a history of self-wounding (SW) when compared to non-wounders (NW). Furthermore, cortisol levels were negatively correlated with rates of self-directed biting. The present study was designed to further characterize the relationships between hypothalamic-pituitary-adrenocortical (HPA) activity, self-wounding, and self-directed biting. Basal 24-h urinary free cortisol excretion, the urinary free cortisol response to a low dose of dexamethasone, and the plasma cortisol response to ACTH were examined in 24 individually housed rhesus monkeys, based on wounding history, i.e. the presence/absence of a veterinary record of self-wounding, and current rates of self-directed biting, i.e. the median split of self-dire...
Self-injurious behavior in male rhesus macaques does not reflect externally directed aggression
Physiology & Behavior, 2003
Self-injurious behaviors (SIB), such as self-biting and self-wounding, have been observed in a small percentage of captive nonhuman primates. Because rhesus monkeys that exhibit SIB also tend to be more aggressive, it was hypothesized that SIB is related to externally directed aggression and is associated with contexts in which physical contact between participants is prevented. The purpose of this study was to test the hypothesized relationship between SIB and outward aggression. Subjects were first presented with videotapes of conspecifics, scenery and a blank screen, and their behavior was recorded. Levels of salivary cortisol, an indicator of stress, were also measured before and after presentation of the videos. Although aggression increased when subjects viewed tapes containing conspecifics, neither cortisol levels nor self-biting behavior varied as a function of tape content. The subjects were then placed in two additional test situations: an empty room and the same room containing an unfamiliar conspecific. Aggression was significantly higher in the stranger condition compared to the empty room condition. The two situations yielded parallel increases in cortisol, suggesting that being alone was just as stressful as being paired with an unfamiliar conspecific. Self-biting rates were also similar in these two conditions. Thus, contrary to our prediction, increases in aggression did not correlate with increases in SIB. These results suggest that under similarly stressful conditions, SIB and externally directed aggression are unrelated.
Neuroscience & Biobehavioral Reviews, 2005
Previous studies have reported hyperactivation of catecholaminergic systems and elevated concentrations of corticotropin-releasinghormone (CRH) in the cerebrospinal fluid (CSF) of child maltreatment victims or combat veterans with post-traumatic stress disorder (PTSD). This study investigated the CSF concentrations of CRH and monoamine metabolites in rhesus macaque mothers that physically abused their infants and had themselves been abused as infants. Ten abusive mothers and 10 controls served as study subjects. All animals were sampled for CSF during pregnancy and the postpartum period. Focal observations of social and maternal behavior were also made. Abusive mothers had significantly higher CSF concentrations of CRH and 5-HIAA than controls. Across both subjects and controls, higher CRH, 5-HIAA and MHPG concentrations were associated with antisocial behavior patterns including a high frequency of maternal aggression, infant rejection, and a low frequency of contacts received from other individuals. These findings are consistent with those of previous primate and human studies and suggest that the neurobiological alterations associated with infant abuse may play an important role in the occurrence of maladaptive behavior in adulthood, including the perpetuation of infant abuse across generations.
Neurogenetics of Aggressive Behavior: Studies in Primates
Current Topics in Behavioral Neurosciences, 2013
Aggressive behavior can have adaptive value in certain environmental contexts, but when extreme or executed inappropriately, can also lead to maladaptive outcomes. Neurogenetic studies performed in nonhuman primates have shown that genetic variation that impacts reward sensitivity, impulsivity, and anxiety can contribute to individual differences in aggressive behavior. Genetic polymorphisms in the coding or promoter regions of the Mu-Opioid Receptor (OPRM1), Corticotropin Releasing Hormone (CRH), Monoamine Oxidase A (MAOA), Dopamine D4 Receptor (DRD4), and Serotonin Transporter (SLC6A4) genes have been shown to be functionally similar in humans and rhesus macaques and have been demonstrated to contribute to individual differences in aggression. This body of literature suggests mechanisms by which genetic variation that promotes aggressivity could simultaneously increase evolutionary success while making modern humans more vulnerable to psychopathology.
Behavior Genetics, 2006
Functional allelic variation in the transcriptional control region of the serotonin transporter and monoamine oxidase A genes has been associated with anxiety-and aggression-related behavior in humans and, more recently, in nonhuman primates. Here, we have genotyped these polymorphic regions in seven species of the genus Macaca. Macaques exhibit exceptional inter-species variation in aggression-related social behavior as illustrated by recent studies showing overlapping patterns of aggression-based social organization grades and macaque phylogeny. We cloned and sequenced two new alleles of the serotonin transporter gene-linked polymorphic region in Barbary and Tibetan macaques. In addition, we observed that species displaying tolerant societies, with relaxed dominance and high levels of conciliatory tendency, were monomorphic for both the serotonin transporter gene and, with the exception of Tonkean macaques, the monoamine oxidase A gene. In contrast, those species known to exhibit intolerant, hierarchical and nepotistic societies were polymorphic at one or more of these loci. Rhesus (M. mulatta), the most intolerant and hierarchical species of macaques, showed the greatest degree of allelic variation in both genes. Additional investigation of a polymorphic repeat in exon III of the dopamine receptor D4 as well as a repeat/single nucleotide polymorphism in the 3Ā¢untranslated region of the dopamine transporter which have both been implicated in the modulation of complex behavior failed to reveal a relationship between allelic variability and social organization grade. Taken together, these findings suggest that genetic variation of serotonergic neurotransmission may play an important role in determining inter-species differences in aggression related behavior in macaques.
Biological Psychiatry, 2005
Background: Allelic variation of the monoamine oxidase A (MAOA) gene has been implicated in conduct disorder and antisocial, aggressive behavior in humans when associated with early adverse experiences. We tested the hypothesis that a repeat polymorphism in the rhesus macaque MAOA gene promoter region influences aggressive behavior in male subjects. Methods: Forty-five unrelated male monkeys raised with or without their mothers were tested for competitive and social group aggression. Functional activity of the MAOA gene promoter polymorphism was determined and genotypes scored for assessing genetic and environmental influences on aggression. Results: Transcription of the MAOA gene in rhesus monkeys is modulated by an orthologous polymorphism (rhMAOA-LPR) in its upstream regulatory region. High-and low-activity alleles of the rhMAOA-LPR show a genotype Ļ« environment interaction effect on aggressive behavior, such that mother-reared male monkeys with the low-activity-associated allele had higher aggression scores. Conclusions: These results suggest that the behavioral expression of allelic variation in MAOA activity is sensitive to social experiences early in development and that its functional outcome might depend on social context.