Function In Nonhuman Primates Research Articles

Laterality of limb function in wild chimpanzees of Gombe National Park: comprehensive study of spontaneous activities

Abstract Resurgence of interest in laterality of hand function in nonhuman primates requires baseline knowledge of spontaneous hand-use in nature, in order to make sense of experimental studies in captivity. We present ethological data on 43 categories of limb movements exhibited by one community of wild chimpanzees ( Pan troglodytes schweinfurthii ) in the Gombe National Park, Tanzania. By focal-subject sampling, 42 individuals were observed at close-range over 4 months during their everyday activities. Laterality of hand function was largely absent, as both pooled results for the group and individual results rarely departed from 50:50 (ambilaterality). Neither age nor sex differences emerged. Nor did it matter if the subject was arboreal or terrestrial, or if the non-active hand was idle or engaged in postural support. Laterality was equally absent for unimanual and bimanual tasks. Lack of lateralization for limb movement in this natural population contrasts with findings of apparent right-handedness in captive chimpanzees. Unnatural postures and biased selection of measures in captive studies may account for these differences.

New characters for the functional interpretation of primate scapulae and proximal humeri.

The study of muscle function in nonhuman primates through the technique of electromyography (EMG) has facilitated the identification of specific functional roles for muscles in particular behaviors. This has led to a more complete understanding of the biomechanics of certain regions of the musculoskeletal system, and should facilitate our ability to identify morphological features useful in the functional interpretation of fossil material. The current paper represents one such investigation of a new set of morphometric characters of the scapula and proximal humerus suggested by EMG analyses of shoulder muscle function. A set of new metric variables were examined on the scapulae and proximal humeri of 25 species of extant anthropoid primates, as well as on casts of scapulae and humeri of three fossil primate taxa. The variables are primarily related to the line of action and attachments of the rotator cuff muscles. The position of the scapular spine, the degree of lateral expansion of the subscapular fossa, the size and shape of the subscapularis insertion facet on the lesser tubercle, and the orientation of the infraspinatus insertion facet on the greater tubercle all appear to successfully sort the extant taxa into locomotor groups. Their appearance on the fossil specimens generally supports previous functional interpretations of each taxon's locomotor abilities based on a variety of other characters, suggesting that these traits are equally applicable to fossil material.

A modest proposal: displacement activities as an indicator of emotions in primates

Displacement activities are behaviour patterns (mostly body care activities) characterized by their apparent irrelevance to the situation in which they appear. Scratching, autogrooming, yawning and body shaking are among the most commonly reported displacement activities in non-human primates. A review of the primate literature indicates that displacement activities tend to occur in situations of psychosocial stress and that their frequency of occurrence is affected by anxiogenic and anxiolytic drugs. In the light of this evidence, it is suggested that displacement activities can be used as indicators of emotional states arising in a variety of primate social interactions. Methodological problems associated with such a use are discussed. The hypothesis that displacement activities may also have a communicative function in non-human primates is not supported adequately by available data.

Monoclonal antibodies against human T cell adhesion molecules--modulation of immune function in nonhuman primates.

The cytotoxic T cell is thought to be a primary effector of allograft rejection. In vitro studies have demonstrated that the interaction between cytotoxic T cells and target cells involves cell surface adhesion molecules that result in conjugate formation, with subsequent antigen recognition, T cell activation, and target cell lysis. Experiments have also demonstrated the ability of monoclonal antibodies with specificity for two human T cell adhesion molecules, lymphocyte function associated (LFA) antigen-1 (LFA-1, CD11a, alpha-chain/CD18, beta-chain) and LFA-2 (CD2), to inhibit conjugate formation in vitro. Studies in a nonhuman primate model were undertaken to determine whether the in vivo administration of monoclonal antibodies with specificity for the alpha chain of LFA-1 (CD11a) or with specificity for CD2 could modulate in vivo T cell function. Cynomolgus monkeys (Macaca fascicularis) received 10 daily intravenous infusions of either anti-CD11a, anti-CD2 or both anti-CD11a and anti-CD2 monoclonal antibodies. Antibody administration was well tolerated and resulted in high levels of circulating murine monoclonal antibody in the peripheral circulation. Nearly all the animals generated antimurine antibodies that were specific for both idiotypic and nonidiotypic determinants of the infused mouse protein. Circulating lymphocytes and T cells were not depleted by treatment with anti-CD11a or anti-CD2 mAbs; in fact, treatment with the combination of anti-CD11a plus anti-CD2 or anti-CD11a alone led to increased numbers of circulating lymphocytes and T cells. Modulation of the LFA-1 molecule on circulating T cells occurred as a result of treatment with anti-CD11a (or the combination of anti-CD11a plus anti-CD2), whereas treatment with anti-CD2 (or anti-CD11a plus anti-CD2) did not result in modulation of the CD2 antigen despite detectable levels of circulating anti-CD2 mAb. In vivo T cell function was assessed by placement of skin allografts. As compared with treatment with saline or a control mAb, allograft survival was significantly prolonged in animals treated with anti-CD11a or combination treatment but not in animals receiving anti-CD2 alone. We conclude that the in vivo administration of anti-LFA-1 mAb may be useful for the blockade of effector T cell activity during allograft rejection, that saturation of antigen and antigen modulation may be important for efficacy of such antibody effects in vivo, and that monoclonal antibodies with specificity for functionally important T cell surface molecules may alter T cell function in vivo without lymphocyte depletion.

Use of the NCTR operant test battery in nonhuman primates

A battery of behavioral tasks, designed to monitor complex "cognitive" functions in nonhuman primates, has been in use for several years at the National Center for Toxicological Research. Subjects performing in this Operant Test Battery (OTB) work for food reinforcers and correct performance in each task contained in the OTB is thought to depend upon a relatively specific brain function. The specific tasks and the functions that they are thought to model are: delayed matching-to-sample (DMTS), short-term memory and attention; incremental repeated acquisition (IRA), learning; temporal response differentiation (TRD), time perception; progressive ratio (PR), motivation; and conditioned position responding (CPR), color and position discrimination. Data from various studies indicate that, in general: 1) OTB responding between subjects follows a normal or near-normal distribution; 2) performance in one task does not correlate very highly with performance in any of the other tasks; 3) females acquire correct OTB responding more rapidly than do males; and 4) the profile of disruption of task performance by acute drug administration varies depending upon drug class.

The performance of human infants on a measure of frontal cortex function, the delayed response task.

The Delayed Response task is the best-established marker of frontal lobe function in nonhuman primates. This article reports the developmental progression of human infants on that task. It is proposed that maturation of prefrontal cortex may make possible these age-related improvements in Delayed Response performance. This would suggest the importance of prefrontal cortex functioning very early in life. Twelve infants (6 male, 6 female) were tested longitudinally every two weeks from 6-12 months of age. Another 36 infants (18 male, 18 female) were tested only once: 12 each at 8, 10, and 12 months. We predicted that infants would improve on Delayed Response over these ages because infants' performance on AB improves during this time, and Delayed Response is very similar to AB. The AB task, devised by Piaget, is used to study cognitive development in infants. The ages over which AB performance improves are well established. In both AB and Delayed Response, the subject watches as the experimenter hides a desired object in one of two identical wells. After a brief delay, the subject is allowed to reach. In AB, the object is hidden in the same well on subsequent trials until the subject reaches to the correct well; then side of hiding is reversed and the procedure repeated. In Delayed Response, side of hiding is varied randomly over trials. In the present study of Delayed Response each testing session consisted of 16 trials (eight to the right, eight to the left). We found: (1) the developmental progression for Delayed Response is almost identical to that for AB. (2) Infants of 7 1/2-9 months fail Delayed Response under the same conditions and in the same ways as do monkeys with lesions of dorsolateral prefrontal cortex. It is therefore suggested that AB and Delayed Response require the same cognitive abilities, and that improved performance on these tasks provides an index of maturation of frontal cortex function.

Lack of platelet monoamine oxidase activity in cebus monkeys (Cebus albifrons)

1. Recent evidence suggests that monoamine oxidase (MAO) plays an important role modulating the extrapyramidal syndromes produced by neuroleptic drugs in both human and nonhuman primates. 2. To evaluate the possibility of using peripheral blood platelet MAO-B levels as indices of central nervous system MAO-B effects, we measured platelet MAO-B levels in Cebus monkeys that were previously tested with neuroleptics ( N = 36) or drug naive ( N = 6). 3. No platelet MAO-B was consistently detectable in these blood samples. 4. Thus platelet measures of MAO-B do not reliably reflect brain MAO-B function in nonhuman primates and do not offer a useful model for studying blood-brain MAO-B relationships.

Gonadal hormones influence the emergence of cortical function in nonhuman primates.

The role of gonadal hormones in the maturation of the orbital prefrontal cortex (ORB) was studied in normal male and female rhesus monkeys, monkeys given ORB lesions at 50 days of age, and female monkeys given androgen at different ages. Monkeys were tested on an object discrimination reversal task at 75 days of age. Gender influenced the performance of monkeys on the task during normal development and after ORB lesions. Normal males made fewer errors than did normal females. Females treated with androgen performed similarly to normal male monkeys. ORB lesions produced deficits in male monkeys and in females given androgen during late prenatal or early postnatal life, but not in normal females. These findings suggest that gonadal hormones may play an inductive role in the differentiation of higher cortical function in nonhuman primates.

Neurobiology of primate audio-vocal behavior

Audio-vocal behavior is an outstanding means of social communication among nonhuman primates and man. Neurobiological studies of this behavior contribute to a better understanding of communication processes in general and of the cerebral prerequisits for the evolution of language and speech in particular. In the first part of the review the cerebral system which generates, selects and controls species-specific vocal behavior is described in anatomical and physiological terms. Its structures and functions are organized in a hierarchical manner whereby the pericingular cortex and the periaqueductal gray are nodal areas in the system. In the second part auditory decoding mechanisms of vocal signals are discussed in terms of cortical ablation studies and response characteristics of single neurons along the auditory pathway. There are marked differences in the processing of natural calls at the collicular, medial geniculate and cortical levels. The cortex makes a necessary contribution to the decoding of complex sounds. References to the problem of lateralization of auditory function in non-human primates are made. A keystone for the understanding of communication processes in general lies in the question of how the signal producing motor system and the signal receiving decoding system is centrally tied together. One way to investigate such processes is to compare single unit responses along the auditory pathway during an animal's own phonation and during the playback of that vocalization. The results provide evidence for an internal feed-forward mechanism during phonation which influences parts of the auditory system.

The activity of γ-linolenate and dihomo-γ-linolenate methyl esters in vitro and in vivo on blood platelet function in non-human primates and in man

γ-linolenate and dihomo-γ-linolenate methyl esters have been shown to be potent inhibitors of adenosine diphosphate-(ADP) induced platelet aggregation in vitro and in vivo . Using fresh human plasma, dihomo-γ-linolenate methyl ester appeared to be approximately twice as potent as the γ-linolenate methyl ester in vitro . Both compounds were shown to be potent inhibitors of ADP-induced platelet aggregation after oral administration to the baboon. At 4mg/kg (p.o.) γ-linolenate methyl ester was inactive when administered daily for 5 days. A potent inhibitory effect was observed with this compound after acute administration at 25 mg/kg by the same route. Dihomo-γ-linolenate methyl ester inhibited ADP-induced platelet aggregation after oral administration at 2 mg/kg for 5 days. Combined with 0.7g Naudicelle oil,∗ dihomo-γ-linolenate methyl ester inhibited platelet aggregation at oral doses of 15, 4 and 1.5 mg/kg respectively, 3 hours after dosing. In man, dihomo-γ-linolenate methyl ester inhibited platelet aggregation at dose levels of 1.5 mg/kg when administered as a single oral dose or daily over a period of 5 days. In the acute study inhibition was observed up to 4 hours after dosing and had normalised after 6 hours. In the chronic study a progressive inhibition was achieved over the 5 day dose period with inhibition 24 hours after dosing on the 3rd day. A possible sex difference in the efficacy of dihomo-γ-linolenate methyl ester was observed in the baboon and in human volunteers, the material being less effective in females.