How many fingers am I holding up? What day of the week is it? Follow my finger? These three questions are designed to test your sensory, memory and motor neural abilities following an accident; all three systems are affected by a severe deceleration of your brain. Despite traumatic brain injury being the leading form of death and long-term injury in young people, the fundamental causes of impaired electrical signalling in neurons, which lead to an incapacitated state, remain largely speculative. This complete lack of a systematic characterisation of the ionic currents affected after traumatic mechanical shock has hindered our understanding of concussion and limited its treatment. More recently the effect of sub-threshold head impacts, as mild as heading a football, have been flung into the spotlight, due to the long-term cumulative consequences they have on the nervous system in later life.
In this cutting-edge novel project you will use advanced electrophysiological techniques to understand the initial and short-term changes in neurons following mechanical injury in an up-and-coming lab. You will receive extensive hands on training in whole-cell patch-clamp and sharp electrode recording methodology from Drs Warren and Steinert. In addition, you will also be trained in genetic techniques, confocal microscopy and biophysics. Your training will be bolstered by attendance at the world-renowned Plymouth Electrophysiology Workshop. You will be part of the thriving neuroscience community within the Department of Neuroscience, Psychology and Behaviour with access to state of the art facilities and tailored career development programmes run by the Doctoral College.
Your project will focus on motor neurons and their well-characterised synapse the NeuroMuscular Junction (NMJ) in the larvae of Drosophila melanogaster; a powerful model organism used to understand facets of human disease. You will use whole-cell patch-clamp recordings from the motor neurons to quantify the changes in ionic currents directly following a mechanical insult. In doing so you will build an all-encompassing understanding of the relative contribution of the ion channel culprits responsible for the effects of concussion. An established molecular target of concussion are glutamatergic synapses and their NMDA receptors. The NMJ is a comprehensively characterised glutamatergic synapse and ideal for understanding how these NMDA receptors are effected after mechanical insult. To measure glutamatergic currents you will be trained in sharp electrode recordings from larval muscles. Your electrophysiologically-focused project will be complemented with behavioural measures of concussion in whole larvae and biophysical measurements of mechanical insults using Doppler lasers with the physicist, James Windmill at the University of Strathclyde in Glasgow. The end goal of your project is to be able to translate your findings and methodology to vertebrate systems such as zebrafish and mammalian brain slices. Future work will develop novel pharmacological interventions for concussion and traumatic brain injury.
Techniques that will be undertaken during the project
Quantification of a mechanical insult is absolutely necessary to target below threshold (sub- concussive) and above threshold injury. We will use a laser Doppler vibrometer housed within the specialist facilities at Strathclyde to measure, with super-fast temporal resolution, acceleration and deceleration of the Drosophila larvae nervous system. Whole-cell patch clamp and sharp electrode recording techniques will systematically quantify the ion channels in the motor neurons and the NMDA receptor currents respectively. Genetic techniques will be used to label target motor neurons and test the role of individual molecules (proteins) in concussion. Locomotory behaviour, will also be used to complement the neurophysiological approach. Through this novel approach a systems level of analysis of behaviour can be explained through single molecule effects of the ion channels.