Meeting Abstract

50.7  Jan. 6  Movement and Body Stretch Encoding by Mechanosensors in Manduca sexta SIMON, M.A.**; TRIMMER, B.A.; Tufts University, Medford, MA; Tufts University, Medford, MA michael.simon@tufts.edu

Caterpillars are soft-bodied, terrestrial climbers capable of a wide variety of complex movements despite a relatively simple nervous system. To navigate successfully, they must adapt their movements in response to sensory information, in particular mechanical forces and deformations. Such mechanoreceptors must be attached to soft tissues, and it is unknown how they encode information or how that information is used to coordinate movement. In the soft-bodied crawler Manduca sexta, one potentially important sensory organ is the longitudinal stretch receptor organ (SRO), a muscle-like tissue anchored to the soft cuticle. Here, we discuss the output of an SRO undergoing stretching stimuli and show that its output includes multiple components. These responses include coding for receptor length and stretch velocity. The output also exhibits adaptation over longer duration stretches but does not appear to directly encode tension. We will also present new evidence regarding how the SRO might be dynamically adjusted by the activity of stretch receptor motoneurons (SRMs). Finally, we will discuss the implications that these results have for our understanding of proprioceptor function and what impact such feedback has on soft-bodied locomotion.