Award details

Nanomechanics of active sensors in insects

Reference	BB/C518522/1
Principal Investigator / Supervisor	Professor Daniel Robert
Co-Investigators / Co-Supervisors	Professor Mervyn Miles, Professor James Windmill
Institution	University of Bristol
Department	Biological Sciences
Funding type	Research
Value (£)	427,420
Status	Completed
Type	Research Grant
Start date	20/04/2005
End date	19/04/2008
Duration	36 months

Abstract

The proposed research will investigate the mechanical and neural processes at work in the auditory organs of insects. Nanoscale and sub-nanoscale sensitivity will be investigated with respect to auditory mechanics and neuronal motility. Mosquitoes, the fruit fly Drosophila and locusts are the model systems of choice for such investigations; they are currently used in our laboratory, they are amenable to the planned experimental procedures and, despite their small size and apparent structural simplicity, they display many of the functional attributes of the auditory organs of mammals. The process of active audition is to date one of the most debated topics in auditory science. In essence, the research programme will examine several key steps in the chain of hearing, from the conversion of acoustic energy into mechanical vibrations of external auditory structures (the antenna), to the mechanical behaviour (deflections) of the mechanoreceptor cells themselves. This will be achieved by conducting a thorough systems analysis of the mosquitos auditory system. In addition to its fundamental contributions, this research will also serve to lay the foundations for future work that will emulate the biological principles and mechanisms of active audition and apply them to technological detection systems. Adding to our fundamental understanding of nanoscale detection, the proposed research has the potential to contribute to a wider realm of scientific research and commercial applications that are pertinent to medicine, environmental science, and materials science. The initial work will be focussed on the installation of the new Atomic Force Microscope (AFM), hearing organ stimuli and insect housing. This will then be used, in combination with the existing microscanning laser vibrometer workstation, to investigate, step by step, how the hearing organ translates changes in air particle velocity into the motion of mechanoreceptor cells. This stepwise analysis is essential; it provides a series of transfer functions characterising energy conduction and dissipation through the entire system. Measurements will thus aim to evaluate the forces and motions undergone and generated by the mechanoreceptors, in the presence of acoustic stimuli, or during thermal fluctuations. The AFM will allow this to be performed at many sites along the mechanoreceptor, providing a rendition of the transduction of energy through the mechanoreceptor structure. A further step will entail combining mechanical stimuli, either to the antenna or to the mechanoreceptor, with electrophysiological measurements of the neural impulses generated by the mechanoreceptor neuron. Thus a direct causal connection between mechanical stimulation and neural activity will be made. At this point, the capacity of the AFM to locally measure neural electrical activity using functionalised probes will be evaluated. The mechanical behaviour of the neurone¿s sensory cilium, the presumed site of mechanoelectric transduction, could thus be probed with a nanometre scale during neuronal activity. This would provide long sought for information about the elusive process of mechanoelectric transduction. Finally, the action of the molecular motors at work within the active mechanoreceptor, again presumably along the sensory cilium, will be investigated by measuring the motion of different parts of the mechanoreceptor using the AFM system. The behaviour of population of mechanoreceptors will also be considered with regard to their cooperative involvement in the process of active auditory mechanics.

Summary

unavailable

Committee	Closed Committee - Animal Sciences (AS)
Research Topics	Neuroscience and Behaviour
Research Priority	X – Research Priority information not available
Research Initiative	X - not in an Initiative
Funding Scheme	X – not Funded via a specific Funding Scheme

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