Primate

About: Primate is a research topic. Over the lifetime, 1250 publications have been published within this topic receiving 67388 citations. The topic is also known as: the primate order & primates.

Three-dimensional stereotactic surface projection analysis of macaque brain PET: development and initial applications.

Abstract: To characterize better the local brain functions of conscious rhesus macaques, we developed automated image analysis techniques for monkey PET images, examined the cerebral glucose metabolism of monkeys, and compared it with that of humans. Methods: Glucose metabolic PET images from 11 monkeys were obtained using a high-resolution animal PET scanner after intravenous administration of FDG. T1-weighted MR images were obtained from 6 of the monkeys. Referencing a bicommissural stereotactic macaque brain atlas, we created a PET brain template using coregistered MR images. Each individual PET image set was transformed to the PET template through an automated affine transformation, followed by nonlinear warping along the directions of the major neuronal fiber bundles in the brain. For minimization of residual anatomic variability, metabolic activities were extracted using 3-dimensional stereotactic surface projections. The effects of anatomic standardization were evaluated using MR images. Patterns of cerebral glucose metabolism of young versus aged monkeys were examined. The metabolic activities of aged monkeys were compared with those of elderly healthy human volunteers that had been analyzed similarly. Results: Anatomic standardization reduced individuals9 anatomic variability as evidenced by a reduction in the number of MR pixels with higher SDs calculated across monkeys. Coefficient-of-variation maps of conscious monkeys revealed that the greatest metabolic variances were near the central sulci and occipital cortices. Age-associated glucose metabolic reductions were most pronounced in the occipital lobe, caudate nucleus, and temporal lobe. Compared with human brains, the monkey frontal lobe and posterior cingulate gyrus had significantly less metabolic activity and the supramarginal gyrus and vermis had significantly more metabolic activity. Conclusion: The proposed method permits pixel-by-pixel characterization of the metabolic activities of rhesus macaque brains in the stereotactic coordinate system. Greater metabolic variances in the central sulcus region and occipital lobe suggest potential difficulties in controlling sensory input and motor output or planning in conscious monkey experiments. The analyses revealed age-related metabolic reductions in monkeys and marked differences in metabolic patterns between aged monkey brains and aged human brains. The proposed brain-mapping technique enables reproducible and observer-independent analyses and will serve as an important investigative tool for primate brain imaging research.

The anterior cingulate cortex is necessary for forming prosocial preferences from vicarious reinforcement in monkeys.

Abstract: A key feature of most social relationships is that we like seeing good things happen to others. Research has implicated the anterior cingulate cortex (ACC) in attaching value to social outcomes. For example, single neurons in macaque ACC selectively code reward delivery to the self, a partner, both monkeys, or neither monkey. Here, we assessed whether the ACC's contribution to social cognition is causal by testing rhesus monkeys (Macaca mulatta) on a vicarious reinforcement task before and after they sustained ACC lesions. Prior to surgery, actors learned that 3 different visual cues mapped onto 3 distinct reward outcomes: to self ("Self"), to the other monkey ("Other"), or to neither monkey ("Neither"). On each trial, actors saw a cue that predicted one of the 3 juice offers and could accept the offer by making a saccade to a peripheral target or reject the offer by breaking fixation. Preoperatively, all 6 actors displayed prosocial preferences, indicated by their greater tendency to give reward to Other relative to Neither. Half then received selective, bilateral, excitotoxic lesions of the ACC, and the other half served as unoperated controls. After surgery, all monkeys retained the social preferences they had demonstrated with the preoperatively learned cues, but this preference was reduced in the monkeys with ACC lesions. Critically, none of the monkeys in the ACC lesion group acquired social preferences with a new set of cues introduced after surgery. These data indicate that the primate ACC is necessary for acquisition of prosocial preferences from vicarious reinforcement.

Cell transcriptomic atlas of the non-human primate Macaca fascicularis

Abstract: Studying tissue composition and function in non-human primates (NHPs) is crucial to understand the nature of our own species. Here we present a large-scale cell transcriptomic atlas that encompasses over 1 million cells from 45 tissues of the adult NHP Macaca fascicularis. This dataset provides a vast annotated resource to study a species phylogenetically close to humans. To demonstrate the utility of the atlas, we have reconstructed the cell-cell interaction networks that drive Wnt signalling across the body, mapped the distribution of receptors and co-receptors for viruses causing human infectious diseases, and intersected our data with human genetic disease orthologues to establish potential clinical associations. Our M. fascicularis cell atlas constitutes an essential reference for future studies in humans and NHPs.

Polymorphic Color Vision in Primates: Evolutionary Considerations

Abstract: Color provides a reliable cue for object detection and identification during various behaviors such as foraging, mate choice, predator avoidance, and navigation The total number of colors that a visual system can discriminate is largely dependent on the number of different spectral types of cone opsins present in the retina and the spectral separations among them Thus, opsins provide an excellent model system to study evolutionary interconnections at genetic, phenotypic, and behavioral levels Primates have evolved a unique ability for three-dimensional color vision (trichromacy) from the two-dimensional color vision (dichromacy) present in the majority of other mammals This development was accomplished via allelic differentiation (eg, most New World monkeys) or gene duplication (eg, Old World primates) of the middle to long wavelength-sensitive (M/LWS, or red–green) opsin gene However, questions remain regarding the behavioral adaptations of primate trichromacy Allelic differentiation of the M/LWS opsins results in extensive color vision variability in New World monkeys, where trichromats and dichromats are found in the same breeding population, enabling us to directly compare visual performances among different color vision phenotypes Thus, New World monkeys can serve as an excellent model to understand and evaluate the adaptive significance of primate trichromacy in a behavioral context In this chapter, we summarize recent findings on color vision evolution in primates and other vertebrates and introduce our genetic and behavioral study of vision–behavior interrelationships in free-ranging sympatric capuchin and spider monkey populations in Costa Rica