Subventions et des contributions :

Subvention ou bourse octroyée s'appliquant à plus d'un exercice financier. (2017-2018 à 2022-2023)

Neuroscientists believe that learning and memory as well as the refinement of neuronal circuits during development are due to changes in synaptic connections among interconnected neurons, known as synaptic plasticity. My team investigates plasticity in neocortex, with a focus on the more recently discovered Spike-Timing-Dependent Plasticity (STDP) paradigm, because of its excellent experimental control and biological plausibility. With classical STDP, pre before postsynaptic firing within a few milliseconds results in strengthening, whereas the opposite temporal order elicits weakening, which effectively enables the brain to learn causal relationships. But synaptic plasticity is known to vary with synapse type -- different mechanisms and phenomenology are found at inputs to different interneuronal classes. Why and how does synaptic plasticity vary? In this Discovery Grant proposal, we aim to confront this issue, using a battery of state-of-the-art methods such as paired recordings, 2-photon imaging, optogenetics, and computer modeling.
Our unpublished data indicate that some interneuronal cell types possess “reversed” STDP at their excitatory inputs, while others do not. This synapse type specificity of STDP is not likely to be coincidental, but important for brain functioning. We will use this as a starting point, and trace out the STDP learning rules of key synapse types in developing visual cortex, while carefully classifying these interneurons based on their morphology, intrinsic firing patterns, and genetic markers. This research program will clarify the rules that govern information storage and rewiring during development of the neocortex. Our efforts will produce cutting-edge scientific results, while at the same time being safe. The proposal would enable three graduate students to learn advanced optical and electrophysiological techniques, and an undergraduate to learn imaging, morphological reconstructions, etc., thus providing an ideal setting for training of highly qualified personnel ranging from the junior to the relatively senior.