|Title: ||Neural basis of a visuo-motor transformation in the fly|
|Authors: ||Huston, Stephen|
|Supervisors: ||Krapp, Holger|
|Issue Date: ||17-Jan-2006|
|Abstract: ||How the outputs of populations of sensory neurons are used by motor systems to
generate appropriate behaviour is a long standing question in neuroscience. I address
this problem by studying a comparatively simple model system. In the fly, Neck
Motor Neurons control gaze-stabilising head movements that occur during wholebody
rotations. These motor neurons receive several sensory inputs including one
from well-characterized visual interneurons, Tangential Cells (TCs), which respond to
panoramic image shifts induced during self-motion.
In chapter one, I provide a general introduction to sensory-motor circuits and the fly
In chapter two, I report that the visual receptive fields of Neck Motor Neurons are
similar to those of the TCs. Using this result, I show an alignment between the
coordinate systems used by the visual and the neck motor systems to process visual
information. Thus, TCs encode visual inputs in a manner already closely matched to
the requirements of the neck motor neurons, considerably facilitating the visual-motor
In chapter three, I analyse the gating of neck motor neuron visual responses by
convergent mechanosensory inputs from the halteres. Some neck motor neurons do
not fire action potentials in response to visual stimuli alone, but they will in response
to haltere movements. I show that visual stimuli produce sustained sub-threshold
depolarisations in these neurons. These visual depolarisations increase the proportion
of haltere-induced action potentials in neck motor neurons. Thus, visual inputs can
only affect the spiking output if the halteres are moving. This simple mechanism
could explain why flies only make visually induced head movements during walking
or flight: behaviours that involve beating the halteres.
By analysing how the outputs of a model sensory system are used, I have shown a
novel alignment between sensory and motor neuron populations and a simple
mechanism underlying multisensory fusion.|
|Appears in Collections:||Theses - Department of Zoology|
This item has been accessed 815 times.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.