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Nicol, C. J., Adachi, M., Akiyama, T. E., & Gonzalez, F. J. (2005). PPARgamma in endothelial cells influences high fat diet-induced hypertension. Am J Hypertens, 18(4 Pt 1), 549–556.
Abstract: BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands improve human hypertension. However, the mechanism and site of this effect remains unknown, confounded by PPARgamma expression in many cell types, including endothelial cells (ECs). METHODS: To evaluate the vascular role of PPARgamma we used a conditional null mouse model. Specific disruption of PPARgamma in ECs was created by crossing Tie2-Cre+ transgenic (T2T+) and PPARgamma-floxed (fl/fl) mice to generate PPARgamma (fl/fl)T2T+ (PPARgamma E-null) mice. Conscious 8- to 12-week-old congenic PPARgamma (fl/fl)Cre- (wild type) and PPARgamma E-null mice were examined for changes in systolic blood pressure (BP) and heart rate (HR), untreated, after 2 months of salt-loading (drinking water), and after treatment for 3 months with high fat (HF) diet alone or supplemented during the last 2 weeks with rosiglitazone (3 mg/kg/d). RESULTS: Untreated PPARgamma E-nulls were phenotypically indistinguishable from wild-type littermates. However, compared to similarly treated wild types, HF-treated PPARgamma E-nulls had significantly elevated systolic BP not seen after normal diet or salt-loading. Despite sex-dependent baseline differences, salt-loaded and HF-treated PPARgamma E-nulls of either sex had significantly elevated HR versus wild types. Interestingly, rosiglitazone improved serum insulin levels, but not HF diet-induced hypertension, in PPARgamma E-null mice. CONCLUSIONS: These results suggest that PPARgamma in ECs not only is an important regulator of hypertension and HR under stressed conditions mimicking those arising in type 2 diabetics, but also mediates the antihypertensive effects of rosiglitazone. These data add evidence supporting a beneficial role for PPARgamma-specific ligands in the treatment of hypertension, and suggest therapeutic strategies targeting ECs may prove useful.
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Miller-Butterworth, C. M., Kaplan, J. R., Barmada, M. M., Manuck, S. B., & Ferrell, R. E. (2007). The Serotonin Transporter: Sequence Variation in Macaca fascicularis and its Relationship to Dominance. Behav Genet, .
Abstract: Specific genotypes of the rhesus monkey and human serotonin transporter gene (SERT) promoter region are associated with personality traits and serotonergic activity. However, the most commonly studied promoter polymorphism (5-HTTLPR) is monomorphic in many other monkey species. To date, no systematic search for alternative potentially functional polymorphisms across the remaining coding parts of the gene has been undertaken in other primate species, despite the crucial role SERT plays in modulating serotonergic tone. We investigated whether sequence variation in this gene is associated with social rank and serotonin metabolite (5-HIAA) differences in 524 cynomolgus macaques. Sequence variation and extent of linkage disequilibrium (LD) across the regulatory and coding regions were initially characterized in 92 macaques. The exons and promoter contained 28 polymorphisms, more than double that recorded for human SERT. In further contrast to humans, the macaque SERT showed no significant LD. Potentially functional polymorphisms were genotyped in all animals. No individual variants or haplotypes were significantly associated with social rank or 5-HIAA concentrations; however, certain serotonin transporter diplotypes may modulate acquisition of dominance status.
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Assersohn, C., Whiten, A., Kiwede, Z. T., Tinka, J., & Karamagi, J. (2004). Use of leaves to inspect ectoparasites in wild chimpanzees: a third cultural variant? Primates, 45(4), 255–258.
Abstract: We report 26 cases of using leaves as tools with which wild chimpanzees (Pan troglodytes schweinfurthii) in the Sonso community, Budongo Forest, Uganda, appeared to inspect objects removed during grooming. Careful removal of potential ectoparasites and delicate lip or manual placement on leaves followed by intense visual examination characterised this behaviour. It appears to be done to judge whether either ingestion or discarding is most appropriate, the former occurring in most cases. This behaviour may represent a third variant of ectoparasite handling, different from those described at Tai and Gombe, yet sharing features with the latter. These two East African techniques may thus have evolved from leaf grooming.
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Gruter, C. C. (2004). Conflict and postconflict behaviour in captive black-and-white snub-nosed monkeys (Rhinopithecus bieti). Primates, 45(3), 197–200.
Abstract: Black-and-white snub-nosed monkeys (Rhinopithecus bieti) have almost never been the subject of any behavioural observations in captivity. This study was aimed at providing preliminary information about agonistic and reconciliation behaviour in a group kept at the Kunming Institute of Zoology in China. Established procedures were used for this investigation (i.e., the postconflict/matched-control method and the time-rule method). Intra-group aggression rates were quite low. Postconflict affiliation as well as selective attraction of former opponents to each other following conflicts was demonstrated. Former opponents contacted each other earlier in postconflict periods than in matched-control periods. The average conciliatory tendency of all focal individuals combined was 54.5%. After an agonistic interaction, the first affiliative contact between former aggressors usually took place within the first minute. The behaviours most often shown as first affiliations after a conflict were body contact, mount, touch, and “hold-lumbar”, of which the latter is an explicit reconciliatory gesture. Furthermore, the adult male intervened non-aggressively in 84% of all conflicts (n=25) among the adult females. Overall, the patterns of aggression and reconciliation observed in R. bieti bear many of the traits that characterise tolerant primate species.
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Murai, C., Tomonaga, M., Kamegai, K., Terazawa, N., & Yamaguchi, M. K. (2004). Do infant Japanese macaques ( Macaca fuscata) categorize objects without specific training? Primates, 45(1), 1–6.
Abstract: In the present study, we examined whether infant Japanese macaques categorize objects without any training, using a similar technique also used with human infants (the paired-preference method). During the familiarization phase, subjects were presented twice with two pairs of different objects from one global-level category. During the test phase, they were presented twice with a pair consisting of a novel familiar-category object and a novel global-level category object. The subjects were tested with three global-level categories (animal, furniture, and vehicle). It was found that they showed significant novelty preferences as a whole, indicating that they processed similarities between familiarization objects and novel familiar-category objects. These results suggest that subjects responded distinctively to objects without training, indicating the possibility that infant macaques possess the capacity for categorization.
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Saucier, D. M., Shultz, S. R., Keller, A. J., Cook, C. M., & Binsted, G. (2007). Sex differences in object location memory and spatial navigation in Long-Evans rats. Anim. Cogn., .
Abstract: In both humans and rodents, males typically excel on a number of tasks requiring spatial ability. However, human females exhibit advantages in memory for the spatial location of objects. This study investigated whether rats would exhibit similar sex differences on a task of object location memory (OLM) and on the watermaze (WM). We predicted that females should outperform males on the OLM task and that males should outperform females on the WM. To control for possible effects of housing environment, rats were housed in either complex environments or in standard shoebox housing. Eighty Long-Evans rats (40 males and 40 females) were housed in either complex (Complex rats) or standard shoebox housing (Control rats). Results indicated that males had superior performance on the WM, whereas females outperformed males on the OLM task, regardless of housing environment. As these sex differences cannot be easily attributed to differences in cognitive style related to linguistic processing of environmental features or to selection pressures related to the hunting gathering evolutionary prehistory of humans, these data suggest that sex differences in spatial ability may be related to traits selected for by polygynous mating strategies.
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Hvorecny, L. M., Grudowski, J. L., Blakeslee, C. J., Simmons, T. L., Roy, P. R., Brooks, J. A., et al. (2007). Octopuses (Octopus bimaculoides) and cuttlefishes (Sepia pharaonis, S. officinalis) can conditionally discriminate. Anim. Cogn., .
Abstract: In complex navigation using landmarks, an animal must discriminate between potential cues and show context (condition) sensitivity. Such conditional discrimination is considered a form of complex learning and has been associated primarily with vertebrates. We tested the hypothesis that octopuses and cuttlefish are capable of conditional discrimination. Subjects were trained in two maze configurations (the conditions) in which they were required to select one of two particular escape routes within each maze (the discrimination). Conditional discrimination could be demonstrated by selecting the correct escape route in each maze. Six of ten mud-flat octopuses (Octopus bimaculoides), 6 of 13 pharaoh cuttlefish (Sepia pharaonis), and one of four common cuttlefish (S. officinalis) demonstrated conditional discrimination by successfully solving both mazes. These experiments demonstrate that cephalopods are capable of conditional discrimination and extend the limits of invertebrate complex learning.
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Suda-King, C. (2007). Do orangutans (Pongo pygmaeus) know when they do not remember? Anim. Cogn., .
Abstract: Metacognition refers to the ability to monitor and control one's own cognitive activities such as memory. Although recent studies have raised an interesting possibility that some species of nonhuman animals might possess such skills, subjects often required a numerous number of training trials to acquire the effective use of metacognitive responses. Here, five orangutans (Pongo pygmaeus) were tested whether they were able to escape spatial memory tests when they did not remember the location of preferred reward in a relatively small number of trials. The apes were presented with two identical cups, under one of which the experimenter hid a preferred reward (e.g., two grapes). The subjects were then presented with a third container, “escape response”, with which they could receive a less preferred but secure reward (e.g., one grape). The orangutans as a group significantly more likely selected the escape response when the baiting of the preferred reward was invisible (as compared to when it was visible) and when the hiding locations of the preferred reward were switched (as compared to when they remained unchanged). Even when the escape response was presented before the final presentation of the memory test, one orangutan successfully avoided the test in which she would likely err. These findings indicate that some orangutans appear to tell when they do not remember correct answers in memory tests.
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Cunningham, E., & Janson, C. (2007). A socioecological perspective on primate cognition, past and present. Anim. Cogn., .
Abstract: The papers in this special issue examine the relationship between social and ecological cognition in primates. We refer to the intersection of these two domains as socioecological cognition. Examples of socioecological cognition include socially learned predator alarm calls and socially sensitive foraging decisions. In this review we consider how primate cognition may have been shaped by the interaction of social and ecological influences in their evolutionary history. The ability to remember distant, out-of-sight locations is an ancient one, shared by many mammals and widespread among primates. It seems some monkeys and apes have evolved the ability to form more complex representations of resources, integrating “what-where-how much” information. This ability allowed anthropoids to live in larger, more cohesive groups by minimizing competition for limited resources between group members. As group size increased, however, competition for resources also increased, selecting for enhanced social skills. Enhanced social skills in turn made a more sophisticated relationship to the environment possible. The interaction of social and ecological influences created a spiraling effect in the evolution of primate intelligence. In contrast, lemurs may not have evolved the ability to form complex representations which would allow them to consider the size and location of resources. This lack in lemur ecological cognition may restrict the size of frugivorous lemur social groups, thereby limiting the complexity of lemur social life. In this special issue, we have brought together two review papers, five field studies, and one laboratory study to investigate the interaction of social and ecological factors in relation to foraging. Our goal is to stimulate research that considers social and ecological factors acting together on cognitive evolution, rather than in isolation. Cross fertilization of experimental and observational studies from captivity and the field is important for increasing our understanding of this relationship.
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Westergaard, G. C., Evans, T. A., & Howell, S. (2007). Token mediated tool exchange between tufted capuchin monkeys (Cebus apella). Anim. Cogn., .
Abstract: Three experiments were conducted to test whether a pair of tufted capuchin monkeys (Cebus apella) could generalize their ability to exchange tokens and tool objects with a human experimenter to similar exchanges with a conspecific partner. Monkeys were tested in side-by-side enclosures, one enclosure containing a tool-use apparatus and one or more token(s), and the other enclosure containing one or more tool object(s). The monkeys willingly transferred tokens and tools to a conspecific with little practice. Following a small amount of training, we also found that the monkeys would select situation-appropriate tokens to exchange for specific tools, but did not select appropriate tool objects in response to another monkey's token transfers. Implications regarding role reversal are discussed.
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