Dynamic optical engine for investigation of neural activity in Drosophila melanogaster

Lead Research Organisation: University of Oxford
Department Name: Engineering Science

Abstract

How behavioural patterns arise from activity in neural circuits is a major question in neuroscience. Understanding this requires researchers to manipulate activity and the connections within a neural network and analyze how electrical impulses travel from one nerve cell to others, and behaviour is generated in a living animal. Electrical signals can in principle be implanted and detected in the brain using direct electrical connections formed by wires. However wire placement is not flexible, is highly invasive and is a particularly limited when working with an animal with a small brain, such as a fruit fly. Alternative light-based methods promise to overcome these limitations by permitting flexible remote stimulation and measurement of neural signals deep within the brain. Laser illumination can activate specific neurons and the resulting activity across a network can be read out using fluorescence microscopy. However, the effectiveness of optical methods is limited by the natural movements of the animals, the light distorting effects of brain tissue and the speed with which one can stimulate and image the neural activity. We will construct an 'optical engine' that will combine various optical methods to overcome these limitations and permit complex interventionist investigations of neural circuit function within the living brain.

Technical Summary

We propose to develop a new tool combining several dynamic optical technologies into a single optical engine that will provide optical actuation and sensing methods to enable neuronal investigations in the living brain. The optical engine will incorporate active beam shaping for the three-dimensional control of photostimulation patterns, correction of aberrations caused by focussing through thick brain tissue, and active focal tracking and stabilisation to compensate for movements of the animal during observation. This will facilitate interrogation of complex neuronal interactions arising from the three-dimensional structure of the brain. We will initially optimise the engine for studies of the brain of the fruit fly, Drosophila melanogaster but it will be generally adaptable for investigation of brain function in vertebrates.

Planned Impact

This proposal concerns the development of new technological tools that will enable neuroscience researchers to both pose and answer important questions about the structure of neural circuits. This research will lead to a better understanding of the causal relationships between neural activity and behaviour. Such scientific progress underpins advancements in medical science that will have benefits for health and quality of life. The introduction of the new tools into the research environment will have immediate benefit, as they will enable more complex investigation of brain function in a range of model animals than is currently possible. Technology developed in this project could potentially lead to commercial exploitation, bringing economic benefit.

Publications

10 25 50
 
Description This research has led to new methods of optical microscopy that will help the understanding of communication between neurons in the brain. The laser based microscopes will enhance scientist's abilities to probe the function of brains of fruit flies to improve knowledge of learning processes and disease models.
Exploitation Route Documentation and publication of the methods via journals and local websites will enable others to reproduce the work.
Sectors Healthcare,Pharmaceuticals and Medical Biotechnology

 
Description The methods are being incorporated into experimental apparatus used for neuroscience and cell biological research.
First Year Of Impact 2014
 
Description ERC Advanced Grant
Amount € 3,234,789 (EUR)
Funding ID 695140 
Organisation European Research Council (ERC) 
Sector Public
Country European Union (EU)
Start 09/2016 
End 08/2021
 
Title Adaptive GPC 
Description A new method for using adaptive feedback control for generalised phase contrast laser beam shaping with applications in optogenetic neural activation. 
Type Of Material Technology assay or reagent 
Year Produced 2014 
Provided To Others? Yes  
Impact Work in progress. 
 
Title Fast 3D microscopy 
Description This new microscope is optimised to perform faster three-dimensional two-photon microscopy, avoiding the speed limitations of standard point scanning laser microscopes. 
Type Of Material Improvements to research infrastructure 
Year Produced 2014 
Provided To Others? Yes  
Impact Preliminary results have been obtained showing the achievable speed and resolution. Impact is expected to follow from use in neuroscience applications. 
 
Description Collaboration Gil Bub 
Organisation University of Oxford
Department Oxford Centre for Magnetic Resonance
Country United Kingdom 
Sector Academic/University 
PI Contribution Provision of optical engineering expertise for the implementation of instrumentation for research project.
Collaborator Contribution Engineering and biological expertise.
Impact Implementation of two microscope systems that are being applied to cardiac and neuroscience research.
Start Year 2016
 
Description Jesper Gluckstad DTU 
Organisation Technical University of Denmark
Country Denmark 
Sector Academic/University 
PI Contribution Expertise in the application of optical methods to neuroscience and biological research.
Collaborator Contribution Intellectual input to the implementation of new Generalised Phase Contrast optical systems.
Impact New method for adaptive generalised phase contrast light control.
Start Year 2013
 
Description Michael Kohl 
Organisation University of Oxford
Department Department of Physiology, Anatomy and Genetics
Country United Kingdom 
Sector Academic/University 
PI Contribution Building new microscope implementation for neuroscience.
Collaborator Contribution Demonstration of impact through use of our new technology.
Impact A new microscope is being built in Oxford.
Start Year 2015