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Activity-dependent plasticity in early olfactory circuits

Supervisor: Elisa Galliano

Co-supervisor: Sue Jones

One of the key questions in modern neurobiology is how the environment influences the brain. How does the brain respond to alterations in experience to modify itself at the cellular level? Since the first demonstration of functional synaptic plasticity, two additional broad classes of neuronal plasticity – intrinsic and structural – have been characterized. Up to now these processes have largely been studied in isolation. Neurons, however, do not singularly adopt plasticity mechanisms, and it has become of primary importance to understand how they combine within individual cells, how they impact information processing in neuronal networks, and how these alterations ultimately affect behavioural choices.

Taking advantage of an array of cutting-edge (i.e. optogenetics and calcium imaging) and time-honoured technologies (i.e. electrophysiology, morphological techniques, behavioural testing), the aim of this project will be to study forms of activity-dependent plasticity in well-defined neuronal populations in the mouse olfactory bulb (OB). Why is studying experience-driven plasticity in the OB a good idea? First, the OB is a well-characterized structure whose input can be readily manipulated due to its proximity to the sensory environment. Second, it is also plastic to such an extent that it is able to regenerate neurons throughout life (i.e. adult neurogenesis). Third, in rodents the olfactory system encodes for robust and ethologically relevant innate and learned behaviours which are easily quantifiable.

Specifically, the proposed PhD project will clarify how different types of physiologically relevant sensory experience induce neuronal plasticity in bulbar neurons in vivo; elucidate how experience-driven plasticity in different neuronal population of embryonic or adult-born neurons affects information processing in OB networks; and investigate how plastic changes at the cellular level modulate olfaction and olfactory-driven behaviours.

 

Relevant references

Tong MT, Peace ST, Cleland TA. (2014) Properties and mechanisms of olfactory learning and memory. Front Behav Neurosci. Jul 7;8:238. Review

Galliano et al (2017) Embryonic and postnatal neurogenesis produce functionally distinct subclasses of dopaminergic neuron. bioRxiv 196006; doi: https://doi.org/10.1101/196006 - under review eLife

Chand AN, Galliano E, Chesters RA, Grubb MS. (2015) A distinct subtype of dopaminergic interneuron displays inverted structural plasticity at the axon initial segment. J Neurosci. Jan 28;35(4):1573-90