Humans belong to the Order Primates, and much of our anatomy and physiology can be best understood in the context of our primate heritage. There is some evidence that one aspect of that heritage may be unique patterns of neural control of limb movements. This proposition is based on observations documenting distinctive limb motions and patterns of muscle use during locomotion in primates compared to other mammals. However, because these uniquely primate aspects of locomotor behavior have been documented for only a handful of monkeys and apes, it is still premature to conclude what is or isn't characteristic of the Order. The current study was initiated to address the most significant gap in this knowledge base, namely, comparable information on the locomotor behavior of the most primitive primates - prosimians. This study will address two specific questions: The first concerns electromyographic documentation of patterns of muscle use during quadrupedal locomotion in prosimian primates. Do prosimian muscle recruitment patterns more closely resemble those of higher primates, those of nonprimates, or do they display some unique pattern of their own? Comparable data have already been collected on three prosimian species, and this proposal will add data for three additional species in order to adequately sample the range of anatomical and locomotor diversity among prosimians. With this completed data set, it will be possible to better characterize muscle use among prosimians, and determine whether previous conclusions are truly characteristic of the entire Order. The second research question focuses on the slow loris, Nycticebus coucang. One surprising aspect of this primate's locomotor mode is an unusual distribution of weight support between its fore- and hind limbs. Since there is currently no satisfactory explanation for how primates achieve their unique distribution of weight support, it is proposed that investigation of an exception to the common pattern may be a key to understanding the pattern itself.
This proposal constitutes a request for continuing support for the Stony Brook Primate Locomotion Laboratory, a facility that has existed for nearly 30 years for the purpose of empirical investigation of the locomotor diversity displayed by humans and nonhuman primates, using state-of-the-art technology to document limb movement patterns, muscle recruitment profiles, and substrate reaction forces. The information collected has been used to address a wide variety of questions concerning form/function relationships that pertain to the evolution of humans and nonhuman primates. In addition to addressing the specific questions outlined above, the Stony Brook University Primate Locomotion Laboratory provides facilities for training both graduate and undergraduate students in the latest experimental methods, and on occasion hosts scholars from other institutions. In addition, the project investigators often supply data and answer specific questions regarding muscle activity patterns, limb use, or distribution of substrate reaction forces during primate locomotion for colleagues at other institutions. The Stony Brook Primate Locomotion Laboratory continues to serve as a major resource for students and senior researchers from around the world.
