Impact cognitif et méchanismes de la plasticité réduite chez les patients avec la maladie du Parkinson

 

Madeleine Sharp

Institut de recherche du Centre universitaire de santé McGill

 

Domaine :  neurosciences, santé mentale et toxicomanies

Programme chercheurs-boursiers - Junior  1

Concours 2017-2018

Learning is a fundamental function of the brain. It is central to healthy human cognition, allowing us to adapt and function at our best. The brain regions that control learning degenerate in Parkinson's and Huntington's disease. Indeed, the vast majority of patients with these diseases experience cognitive symptoms, which are a major contributor to reduced quality of life. And yet we know very little about the brain mechanisms behind these cognitive symptoms, and therefore have no satisfactory treatments.  

We hypothesize that studying learning mechanisms in patients with Huntington's and Parkinson's will provide a mechanistic understanding of why the changes in the brains of these patients lead to cognitive dysfunction. The three proposed projects each focus on a different stage of learning (acquisition, long-term memory and sleep consolidation) that is relevant to the particular patients being studied.

In Project 1 we will test the hypothesis that Huntington's patients develop apathy and depression because they do not learn effectively about rewards and therefore don't pursue them. If this is true, ways could be developed to more effectively orient patients to rewards.

In Project 2 we will test the hypothesis that Parkinson's patients lose the ability to prioritize information for long-term memory storage, which could explain the lack of focus and slower cognitive processing that these patients so often describe. We will also test if dopamine medications improve memory by restoring normal prioritization.

In Project 3 we will test the hypothesis that abnormal sleep patterns in Parkinson's patients interfere with the normal memory strengthening (or consolidation) that occurs during sleep.

It is only through a mechanistic understanding of cognitive deficits in Parkinson's and Huntington's patients that we will be able to develop effective ways of measuring and treating these devastating symptoms.