Categorization and conceptual behavior in nonhuman primates

This essay describes some of the studies that have been carried out in the past 5 years with two species of baboons, both in laboratory-controlled conditions (Guinea baboons, Papio papio) and in outdoor settings (olive baboons, Papio anubis)

Processing of above/below categorical spatial relations by baboons (Papio papio)

Three video-formatted experiments investigated the categorization of ‘above’ and ‘below’ spatial relations in baboons (Papio papio). Using an identity matching-to-sample task, six baboons correctly matched line–dot stimuli based on the ‘above’ or ‘below’ location of the dot relative to the line (Experiment 1). Positive transfer of performance was then observed when the line–dot distance depicted in the sample stimulus differed from that of the two comparison stimuli (Experiment 2). Using a go:nogo procedure, two baboons were further trained to discriminate whether a ‘B’ character was displayed ‘above’ or ‘below’ a ‘3’ character (Experiment 3). After training, a positive transfer of performance was observed with the same type of stimuli depicted in different type fonts. Altogether, these results suggest that baboons may form conceptual representations of ‘above’ and ‘below’ spatial relations, and categorize visual forms on that basis

Metagenomic analysis of dental calculus in ancient Egyptian baboons

Dental calculus, or mineralized plaque, represents a record of ancient biomolecules and food residues. Recently, ancient metagenomics made it possible to unlock the wealth of microbial and dietary information of dental calculus to reconstruct oral microbiomes and lifestyle of humans from the past. Although most studies have so far focused on ancient humans, dental calculus is known to form in a wide range of animals, potentially informing on how human-animal interactions changed the animals' oral ecology. Here, we characterise the oral microbiome of six ancient Egyptian baboons held in captivity during the late Pharaonic era (9th-6th centuries BC) and of two historical baboons from a zoo via shotgun metagenomics. We demonstrate that these captive baboons possessed a distinctive oral microbiome when compared to ancient and modern humans, Neanderthals and a wild chimpanzee. These results may reflect the omnivorous dietary behaviour of baboons, even though health, food provisioning and other factors associated with human management, may have changed the baboons' oral microbiome. We anticipate our study to be a starting point for more extensive studies on ancient animal oral microbiomes to examine the extent to which domestication and human management in the past affected the diet, health and lifestyle of target animals

Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys

We transplanted kidneys from α1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GalT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GalT-KO pigs to humans. © 2005 Nature Publishing Group

Evaluation of performance impairment by spacecraft contaminants

The environmental contaminants (isolated as off-gases in Skylab and Apollo missions) were evaluated. Specifically, six contaminants were evaluated for their effects on the behavior of juvenile baboons. The concentrations of contaminants were determined through preliminary range-finding studies with laboratory rats. The contaminants evaluated were acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), trichloroethylene (TCE), heptane and Freon 21. When the studies of the individual gases were completed, the baboons were also exposed to a mixture of MEK and TCE. The data obtained revealed alterations in the behavior of baboons exposed to relatively low levels of the contaminants. These findings were presented at the First International Symposium on Voluntary Inhalation of Industrial Solvents in Mexico City, June 21-24, 1976. A preprint of the proceedings is included

Associative learning in baboons and humans: Species differences in learned attention to visual features

We examined attention shifting in baboons and humans during the learning of visual categories. Within a conditional matching-to-sample task, participants of the two species sequentially learned two two-feature categories which shared a common feature. Results showed that humans encoded both features of the initially learned category, but predominantly only the distinctive feature of the subsequently learned category. Although baboons initially encoded both features of the first category, they ultimately retained only the distinctive features of each category. Empirical data from the two species were analyzed with the 1996 ADIT connectionist model of Kruschke. ADIT fits the baboon data when the attentional shift rate is zero, and the human data when the attentional shift rate is not zero. These empirical and modeling results suggest species differences in learned attention to visual features

Reaction to spatial novelty and exploratory strategies in baboons

Exploratory activity was examined in 4 young baboons with the aim of investigating the type of spatial coding (purely geometric and/or by taking into account the identity of the object) used for the configuration of objects. Animals were individually tested in an outdoor enclosure for their exploratory reactions (contact time and order of spontaneous visits) to changes brought about to a configuration of different objects. Two kinds of spatial changes were made: a modification (1) of the shape of the configuration (by displacement of one object) and (2) of the spatial arrangement without changing the initial shape (exchanging the location of two objects). In the second experiment, the effect of a spatial modification of the global geometry constituted by four identical objects was investigated. Finally, in the third experiment, a substitution of a familiar object with a novel one was performed without changing the objects' configuration. The baboons strongly reacted to geometrical modifications of the configuration. In contrast, they were less sensitive to modifications of local features that did not affect the initial spatial configuration. Analyses of spontaneous exploratory activities revealed two types of exploratory strategies (cyclic and back-and-forth). These data are discussed in relation to (1) the distinction between the encoding of geometric versus local spatial features and (2) the spatial function of exploratory activity

Cytokine expression in malaria-infected non-human primate placentas

Malaria parasites are known to mediate the induction of inflammatory immune responses at the maternal-foetal interface during placental malaria (PM) leading to adverse consequences like pre-term deliveries and abortions. Immunological events that take place within the malaria-infected placental micro-environment leading to retarded foetal growth and disruption of pregnancies are among the critical parameters that are still in need of further elucidation. The establishment of more animal models for studying placental malaria can provide novel ways of circumventing problems experienced during placental malaria research in humans such as inaccurate estimation of gestational ages. Using the newly established olive baboon (Papio anubis)-Plasmodium knowlesi (P. knowlesi) H strain model of placental malaria, experiments were carried out to determine placental cytokine profiles underlying the immunopathogenesis of placental malaria. Four pregnant olive baboons were infected with blood stage P. knowlesi H strain parasites on the one fiftieth day of gestation while four other uninfected pregnant olive baboons were maintained as uninfected controls. After nine days of infection, placentas were extracted from all the eight baboons through cesarean surgery and used for the processing of placental plasma and sera samples for cytokine sandwich enzyme linked immunosorbent assays (ELISA). Results indicated that the occurrence of placental malaria was associated with elevated concentrations of tumour necrosis factor alpha (TNF-{\alpha}) and interleukin 12 (IL-12). Increased levels of IL-4, IL-6 and IL-10 and interferon gamma (IFN-{\gamma}) levels were detected in uninfected placentas. These findings match previous reports regarding immunity during PM thereby demonstrating the reliability of the olive baboon-P. knowlesi model for use in further studies.Comment: Open Veterinary Journal 1st June 2012. Seven pages, Three Figures. arXiv admin note: text overlap with arXiv:1201.323