RAPID: Sensorimotor function in complex environments in a primate neuroanatomical model species

University Of Southern California, Los Angeles CA

Investigators

Abstract

Humans rely on visual cues to navigate complex terrain safely and stably. This project uses a primate model to investigate how visual and locomotor adaptations that occurred during early primate evolution shaped strategies for navigating complex environments. Major evolutionary transitions in both the visual and locomotor systems took place in our tree-dwelling early primate ancestors. However, it is not fully understood how animals with visual and locomotor systems similar to those of early primates approach specific sensorimotor challenges posed by environmental complexity. The investigators examine how primates move through complex environments by addressing questions related to the mechanics of movement as well as the spatial relationships between visual gaze and foot placement. The findings have the potential to benefit society by providing data necessary to understand how human integrated visual and motor function evolved, thus providing insights into addressing dysfunction in these systems. The project also enhances education by providing STEM learning and training opportunities for undergraduate students. Early primates inhabited a discontinuous, three-dimensional, visually obstructed, and variably illuminated arboreal habitat that posed substantial biomechanical and visual challenges. Comparative studies of locomotion, visual adaptations, and neuroanatomy have shown that primates evolved specialized cortical processing of visual signals, and relatively greater cortical control over patterns of limb movement during locomotion, all while facing the selective pressures of life in a challenging arboreal environment. However, there is limited understanding about how non-human primates navigate environments that mimic the complexity of the natural habitats in which these adaptations arose. This project addresses the following fundamental questions: 1) How do primates move through arboreal habitats that are visually and mechanically challenging? 2) Did the patterns of visually guided locomotion observed in humans emerge early in primate evolution along with other visual and locomotor adaptations? The project involves data collection on forces, joint angles, and gaze behavior during navigation of complex substrates and with varied light conditions in a nocturnal strepsirrhine primate. The species is an appropriate model because it is a generalized arboreal quadruped and its visual system is likely similar to that of the earliest primates. Results from this project can facilitate synthesis of comparative experimental data on non-human primates and existing neuroanatomical data to improve our understanding of integrated visuomotor function in humans. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.