MEM-ENTO : Tracing memory formation in a behaving animal: analysis of learning-induced morpho-functional plasticity along the bee’s olfactory system
Marie-Sklodowska Curie Fellowship - SEP210618144
Memory formation and extinction are fascinating aspects of brain functions. Observation of ex vivo and in vitro experiments provided a framework for understanding associative memory-related plasticity. However, memories are generated via local neuronal interactions within the context of their global networks, and understanding their formation requires in vivo studies in naturalistic conditions, which remain technically challenging. The aim of this MSC project is exploiting a functional calcium imaging approach to investigate memory formation and extinction in behaving honeybees. I will adopt the honeybee as a model system because of the accumulated knowledge on associative learning, the availability of a behavioural read-out for both appetitive and aversive memory formation, and its robustness, which allows for long-lasting imaging experiments. I will focus on its olfactory system because of the optical accessibility, and its analogy with the vertebrate one. Previous works have established the methods for honeybee brain imaging analysis in vivo during appetitive and aversive conditioning. Within this project, I will perform long-term imaging experiments in behaving animals, while monitoring the process of short and long-term memory formation and extinction in the three main neuropils of the olfactory system: the antennal lobe (the primary odour processing centre), the mushroom bodies (possibly dedicated to odour recognition), and the lateral horn (involved in odour valence evaluation). My specific goals are (1) characterizing the morphological and functional changes induced by associative learning throughout these neuropils, (2) highlighting the functional dynamics of a stimulus representation during short and long-term memory formation and extinction, and (3) comparing the memory engram of positive and negative associations.
Neural coding of coding of odour space
An olfactory stimulus reaching the antennae of an insect activates a subpopulation of olfactory receptor neurons. In turn, they will relay the olfactory information to the first odor processing centre of the insect nervous system: the antennal lobe. Each odorant - or odour mixture - will interact in a specific manner with the available olfactory receptors, and produce a stimulus specific activity patter in the antennal lobe. Combining neuronal labelling, calcium imaging, and olfactory stimulation, I study if and how stimuli hitting different segments of the long cockroach's antennae are encoded differently within the cockroach brain. Is the cockroach is capable of mapping the spatial distribution of odorants in the surrounding environment?
Project in collaboration with: Giovanni Galizia - University of Konstanz Einat Couzin-Fuchs - University of Konstanz Hiroshi Nishino - Sapporo University |
Confocal microscopy imaging of half brain of P. americana. Antennal lobe was injected with a fluorescent tracer to visualise all output neurons tracts.
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Functional connectivity analysis
By means of two-photon calcium imaging we can obtain high spatial and temporal resolution recordings of the antennal lobe network. We can then study how functional connectivity of the nodes of this local network changes from resting to "stimulus" state, how it evolves with time and how it responds to different type of stimuli.
Project in collaboration with:
Albrecht Haase - University of Trento
Luca Faes - University of Palermo
Yuri Antonacci - Sapienza University - Rome
Project in collaboration with:
Albrecht Haase - University of Trento
Luca Faes - University of Palermo
Yuri Antonacci - Sapienza University - Rome