Project Summary
The ability to produce spatially and contextually dependent motor responses depends on the nervous
system’s capacity to spatially localize tactile signals. How these computations are accomplished and how the
diversity of neuronal cell-types contribute to network function is not well understood. This project will investigate
how patterns of synaptic connectivity between diverse cell-types in the nervous system contribute to the spatial
localization of tactile stimuli.
The Tuthill lab is a collaborative and multifaceted team studying proprioception and sensorimotor
processing in Drosophila melanogaster. This project will integrate information from different parts of the
sensorimotor pathway while focusing on neural circuits involved in tactile information processing. Specifically, it
will investigate how tactile sensory information from the leg is represented topographically in the ventral nerve
cord (VNC) of the fly. This will be done by mapping the morphologies and projection patterns of tactile
mechanosensory neurons using spatially selective genetic labeling techniques. Moreover, the fine morphology
and synaptic connectivity patterns of individual sensory neuron axons will be reconstructed using volumetric
electron microscopy image data. To characterize important cell-types in the tactile circuit, interneurons in the
VNC that receive synaptic input from the tactile mechanosensory neurons will also be reconstructed. This will
involve predicting the cell-type identity of these cells based on morphology, synaptic connectivity, and local
shape features, all of which can be derived from large scale electron microscopy. This will shed light on the
diverse neuronal types involved in tactile sensory networks as well as the anatomical features that define such
types. Finally, theoretical modeling techniques will be applied to elucidate how the architecture of tactile circuits
define the spatial representation of tactile sensation and how that may predict the spatial acuity of the fly in
response to stimulation. This involves developing a model that represents tactile mechanosensory neurons from
different areas on the leg and their downstream partners in the VNC. Constrained by the synaptic connectivity,
this model will predict the spatial resolution with which flies can distinguish tactile stimulation on the leg. Overall,
this project will examine how individual connections between neurons contribute to tactile sensory encoding and
elucidate how deficits in the tactile circuit may affect spatial localization.