La plasticité synaptique dans les microcircuits néocorticaux / Synaptic Plasticity in Neocortical Microcircuits

 

Per Jesper Sjostrom

Institut de recherche du Centre universitaire de santé McGill

 

Domaine : neurosciences, santé mentale et toxicomanies

Programme Chercheurs-boursiers - Senior

Concours 2018-2019

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, a concept known as synaptic plasticity. How the young brain is wired up as it grows and develops is still not fully understood. We therefore study learning and memory in cells of the visual brain region as a model for learning in other brain regions. Synaptic plasticity is complex. It varies with cell type, because different cell types have different functions in the brain. To understand these functions, we investigate the different forms of plasticity that different brain cells are equipped with. The properties of different forms of synaptic plasticity are determined by their mechanisms, so to understand learning in brain we investigate these different mechanisms.

For example, it should be possible to turn learning on and off so that only useful information is learned in the brain. We have discovered one such switch in the brain. We also study the consequences of synaptic plasticity. For example, synaptic plasticity is needed to wire up the visual brain regions correctly so that we can see. But synaptic plasticity is also often involved when things go wrong. For example, sudden damage to the brain may produce too much activity in brain cells, which may via plasticity generate epilepsy in an otherwise healthy brain. Elucidating how synaptic plasticity works is thus essential for understanding brain functioning in health as well as in disease.