Comparison of object manipulation among 74 species of non-human primates

Seventy-four primates species (24 genera of six families) were presented with a nylon rope and a wooden cube, and their subsequent manipulations were recorded in detail. Five hundreds and six manipulation patterns were distinguished on the basis of the actions performed, body-parts used and relations to other objects. Inter-specific comparisons revealed three groups: (1) lemurs, marmosets, spider monkeys and leaf-eaters; (2) Old World monkeys except leaf-eaters; and (3) cebus monkeys and apes. The first group had the smallest repertoire of manipulations, in which only a few types of actions and body-parts were involved. The second and third groups had more varied modes of manipulation. Actions such as Roll, Rub and Slide, and use of fingers characterized these groups. Except for the lesser ape, their manipulations were frequently related with other objects. Moreover, actions such as Drape, Drop, Strike, Swing and Throw were typical of the third group. The factors producing such inter-specific differences in manipulations and the relations to tool use are discussed.     

Functional organization of cerebral cortical areas at rest in five-, six-, and seven-year-old children

The coherence functions of the main EEG rhythmical components in five-, six-, and seven-year-old children were analyzed. The results of factor analysis showed four types of the basic structure of cortico-cortical interactions at rest. It was shown that these structures are rather stable; however, some of their connections change with age, reflecting the general trend of gradual heterochronous maturation of cerebral cortical areas.     

Electromechanical potentials in cortical bone--II. Experimental analysis

The electrokinetic model developed in Part 1 of this paper is used to characterize the electromechanical effect in cortical bone. Low frequency characteristics of stress-generated potentials are measured to provide insight into the origin and generation of these potentials induced in fluid-filled cortical bone. The results support the proposed model and indicate that fluid movement within the microporosity of bone is responsible for observed potentials whose origin is electrokinetic. The microporosity in bone, composed of the fluid spaces in and around mineral crystals encrusting collagen fibrils, constitutes an enormous surface area and appears to dominate surface-related phenomena at low frequencies. Previous experimental results, reported by many researchers, are also supported by this mechanism.     

Theophylline antagonizes flurazepam-induced depression of cerebral cortical neurons.

Intravenously administered theophylline (50--100 mg/kg) antagonized the depressant actions of adenosine and flurazepam on rat cerebral cortical neurons. When assessed in conjunction with recent reports that theophylline competes with diazepam for binding sites in brain tissue, this finding suggests that one action of the benzodiazepines may be exerted at a purinergic receptor associated with central neurons.     

Perspectives on object manipulation and action grammar for percussive actions in primates

The skill of object manipulation is a common feature of primates including humans, although there are species-typical patterns of manipulation. Object manipulation can be used as a comparative scale of cognitive development, focusing on its complexity. Nut cracking in chimpanzees has the highest hierarchical complexity of tool use reported in non-human primates. An analysis of the patterns of object manipulation in naive chimpanzees after nut-cracking demonstrations revealed the cause of difficulties in learning nut-cracking behaviour. Various types of behaviours exhibited within a nut-cracking context can be examined in terms of the application of problem-solving strategies, focusing on their basis in causal understanding or insightful intentionality. Captive chimpanzees also exhibit complex forms of combinatory manipulation, which is the precursor of tool use. A new notation system of object manipulation was invented to assess grammatical rules in manipulative actions. The notation system of action grammar enabled direct comparisons to be made between primates including humans in a variety of object-manipulation tasks, including percussive-tool use.     

Genetic manipulation of calcium-handling proteins in cardiac myocytes. I. Experimental studies

Two genetic experimental approaches, de novo expression of parvalbumin (Parv) and overexpression of sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a), have been shown to increase relaxation rates in myocardial tissue. However, the relative effect of Parv and SERCA2a on systolic function and on beta-adrenergic responsiveness at varied pacing rates is unknown. We used gene transfer in isolated rat adult cardiac myocytes to gain a fuller understanding of Parv/SERCA2a function. As demonstrated previously, when Parv is expressed in elevated concentration (>0.1 mM), the transduced myocytes showed a reduction in sarcomere-shortening amplitude: 129 +/- 17, 81 +/- 8, and 149 +/- 14 nm for control, Parv, and SERCA2a, respectively. At physiological temperature, shortening amplitude responses of Parv and SERCA2a myocytes to the beta-adrenergic agonist isoproterenol (Iso) were not statistically different from that of control myocytes. However, in SERCA2a myocytes, in which baseline was slightly elevated and the Iso-stimulated value was slightly lower, the increase in shortening was slightly less than in Parv or control myocytes: 108 +/- 14, 169 +/- 39, and 34 +/- 12% for control, Parv, and SERCA2a, respectively. In another test set, Parv myocytes had the strongest early postrest potentiation among all groups studied (rest time = 2-10 s), and SERCA2a myocytes were the least sensitive to variations in stimulation rhythm. To replicate the deficient Ca2+ removal observed in heart failure, we used 150 nM thapsigargin. Under these conditions, control myocytes exhibited slowed relaxation, whereas Parv myocytes retained their rapid kinetics, showing that Parv is still able to control relaxation, even when SERCA2a function is impaired.     

Experimental manipulation of succession in heathland ecosystems

An experiment was carried out in two heathland ecosystems, one dominated by Calluna vulgaris and the other by Molinia caerulea, to analyse the effects of soil organic matter accumulation and nutrient mineralization on plant species dynamics during succession. The experiment included one treatment that received nutrient solution and two treatments where the rate of soil organic matter accumulation was reduced by removing litter or accelerated by adding litter. In a fourth treatment the C. vulgaris litter produced in the C. vulgaris-dominated plots was replaced by litter of M. caerulea and vice versa. Treatments were applied over 8 years. Addition of nutrient solution caused C. vulgaris to decline, and grass species to increase sharply, compared to the control plots. Addition of litter enhanced both N mineralization and the biomass of M. caerulea and Deschampsia flexuosa but reduced the biomass of C. vulgaris. The effects of replacing C. vulgaris litter by M. caerulea litter, or vice versa, on N mineralization and species dynamics could not be attributed to differences between the decomposability of the different litter materials that were transferred. The results confirm the hypothesis that increased litter inputs accelerate the rate of species replacement during succession.     

Priority areas for conservation of primates in a threatened Amazonian savanna

Primates are globally recognized as an important component of biodiversity, however, more than half of primate species in the world are threatened and agriculture expansion is one of the main threats. Brazil has one of the largest networks of protected areas (PAs) in the world, but there are some conservation gaps, such as the Amazonian savannas. We aim to identify a network of priority areas to conserve a Brazilian Amazonian savanna highly threatened by agriculture expansion, by using seven primate species and four vegetation types as targets. We constructed species distribution models (SDMs) for the primates and used a Systematic Conservation Planning approach. We defined as a quantitative conservation target the proportion of the distribution of each primate species within the network according to traits related to their vulnerability to extinction. In addition, we set a target of including at least 30% of each savanna type within priority areas. We created a map of potential use of the land for agriculture and another of environmental risk, which were included as costs in the decision process, and together with the SDMs and vegetation types, identified the network of priority areas by using the software Marxan. We evaluated the feasibility of implementing conservation actions, such as establishing Conservation Units (e.g. reserves managed by the government), or implementing community-based conservation actions in each priority area. Additionally, we estimated the economic investment (US$/year) required to establish Conservation Units across the priority areas. Conservation targets for primates and vegetation types were met by protecting 3,240 km² of the Savannas of Amapá. An investment of approximately US$958,122/year over five years is required to turn these priority areas into Conservation Units, however, we propose other strategies such as conservation on community lands and public policies. All these strategies would allow for protecting forest cover and the heterogeneous environments that are suitable for primates and other biodiversity components.     

Experimental Brugia pahangi and B. malayi infections of callitrichid primates

The callitrichid primates, Callithrix jacchus jacchus (the marmoset) and Saguinus labiatus (the tamarin) were inoculated with infective larvae of Brugia malayi and B. pahangi. Microfilaraemia at low levels developed in 3 out of 4 C.j. jacchus infected with B. malayi and living or dead adult worms found in all 4. Only one of 4 C.j. jacchus became microfilaraemic (mf + ve) when given B. pahangi and adults were found in two. Of 4 S. labiatus given B. pahangi one became very lightly mf + ve and adults were found in 3. It is concluded that these animals are not suitable hosts for chemotherapeutic experiments.     

Experimental manipulation of natural plant communities

Attempts to elucidate the factors controlling the structure of plant communities have relied increasingly on field experiments. This is a powerful approach for testing theoretical predictions that offers important advantages over observational and comparative studies. However, field experiments suffer from intrinsic difficulties as well as more-easily remediable limitations. Recent progress has been made by new approaches including the use of multifactor experiments, and the development and dissemination of better statistical tools.     

Stimulation of cerebral cortical synaptosomal Na-K-ATPase by biogenic amines.

The amines noradrenaline, dopamine, 5-hydroxytryptamine, and histamine (0.01-0.5 mM) enhanced the activity of Na-K-ATPase (EC 3.6.1.3) in rat cerebral cortical synaptosomal fractions. The activities of Mg-ATPase and Ca-Mg-ATPase were not significantly affected. No stimulation of Na-K-ATPase occurred in the presence of chelating agents (0.5 mM EGTA or EDTA) unless 0.5 mM calcium had also been added to the incubation medium. These results are consistent with the hypothesis that amines depress cerebral cortical neurones by activation of an electrogenic sodium pump. Calcium ions appear to be involved in this process.     

Synchronization of neuronal assemblies in reciprocally connected cortical areas

Summary To investigate scene segmentation in the visual system we present a model of two reciprocally connected visual areas comprising spiking neurons. The peripheral area P is modeled similar to the primary visual cortex, while the central area C is modeled as an associative memory representing stimulus objects according to Hebbian learning. Without feedback from area C, spikes corresponding to stimulus representations in P are synchronized only locally (slow state). Feedback from C can induce fast oscillations and an increase of synchronization ranges (fast state). Presenting a superposition of several stimulus objects, scene segmentation happens on a time scale of hundreds of milliseconds by alternating epochs of the slow and fast state, where neurons representing the same object are simultaneously in the fast state. We relate our simulation results to various phenomena observed in neurophysiological experiments, such as stimulus-dependent synchronization of fast oscillations, synchronization on different time scales, ongoing activity, and attention-dependent neural activity.     

Experimental gastric carcinogenesis in Cebus apella nonhuman primates

The evolution of gastric carcinogenesis remains largely unknown. We established two gastric carcinogenesis models in New-World nonhuman primates. In the first model, ACP03 gastric cancer cell line was inoculated in 18 animals. In the second model, we treated 6 animals with N-methyl-nitrosourea (MNU). Animals with gastric cancer were also treated with Canova immunomodulator. Clinical, hematologic, and biochemical, including C-reactive protein, folic acid, and homocysteine, analyses were performed in this study. MYC expression and copy number was also evaluated. We observed that all animals inoculated with ACP03 developed gastric cancer on the 9(th) day though on the 14(th) day presented total tumor remission. In the second model, all animals developed pre-neoplastic lesions and five died of drug intoxication before the development of cancer. The last surviving MNU-treated animal developed intestinal-type gastric adenocarcinoma observed by endoscopy on the 940(th) day. The level of C-reactive protein level and homocysteine concentration increased while the level of folic acid decreased with the presence of tumors in ACP03-inoculated animals and MNU treatment. ACP03 inoculation also led to anemia and leukocytosis. The hematologic and biochemical results corroborate those observed in patients with gastric cancer, supporting that our in vivo models are potentially useful to study this neoplasia. In cell line inoculated animals, we detected MYC immunoreactivity, mRNA overexpression, and amplification, as previously observed in vitro. In MNU-treated animals, mRNA expression and MYC copy number increased during the sequential steps of intestinal-type gastric carcinogenesis and immunoreactivity was only observed in intestinal metaplasia and gastric cancer. Thus, MYC deregulation supports the gastric carcinogenesis process. Canova immunomodulator restored several hematologic measurements and therefore, can be applied during/after chemotherapy to increase the tolerability and duration of anticancer treatments.     

Experimental manipulation of cell surface to affect cellular recognition mechanisms.

The mechanism of selective cell adhesion was studied using Chinese hamster V79 and chick embryonic neural retinal cells. Both of these cell types have been shown to have two experimentally separable mechanisms of adhesion; Ca²⁺-dependent and Ca²⁺-independent. Cells can be dispersed so that either or both of the mechanisms remain intact by use of different treatments. A method of labeling cells with FITC was devised to identify one of the two types of cells in a binary cell population. When cells with one of the two adhesion mechanisms were mixed with cells with the other mechanism, they segregated completely, forming independent aggregates, not only in the heterotypic combination of these cell types but also in the homotypic combination of each cell type. In contrast, when cells were mixed with others with the same adhesion mechanism, either Ca²⁺-dependent or -independent, they formed chimeric aggregates, even in the heterotypic cell combination. These results suggest that the specificity in each of those two mechanisms of cell adhesion plays an important role in cellular recognition processes.     

Scaling of limb joint surface areas in anthropoid primates and other mammals

Recently it was reported that limb joint surface areas scale positively allometrically with body weight in anthropoid primates. This was attributed to the biomechanics of weight bearing: larger animals must require relatively larger joint surfaces to withstand relatively greater weight-related stresses on the joints. Our data on humeral and femoral geometry and joint surface areas in 73 species belonging to six mammalian orders (including primates) demonstrate that positive allometry of joint surface areas is not a general phenomenon for mammals and cannot have its basis among Anthropoidea in the biomechanics of weight bearing. We argue that, to the extent that positive allometric scaling of joint surface areas occurs in anthropoid primates, it is an artifact of differences in positional behaviour among distinct taxonomic groups that also happen to differ widely in body weight. Furthermore, we argue that, among mammals ranging in body size from sportive lemurs to giant pandas, functionally similar groups tend to exhibit: (1) linear dimensions (especially diameters and shaft circumferences) that scale in direct proportion to each other; and (2) joint surface areas that scale in direct proportion to the squares of linear dimensions and to the 2/3 power of body mass. In other words, limb bones of functionally similar animals fit the theoretical model of geometric similarity (or skeletal isometry). Differences in relative sizes of joint surface areas are related to differences in force transmission and movement potential among functionally distinct groups of animals.