Dissecting corticostriatal circuit involvement in action learning through reinforcement

  • Mosberger, Alice (PI)

Project: Research project

Project Details

Description

According to current models of action learning through trial and error, if a random exploratory action leads to reward, certain dimensions of the action are assigned with credit for the reward - the dimensions are reinforced. Through reselection of those dimensions it is established which aspects of the action are contingent with the reward - the action is refined through practice. The striatum is crucial for this process of action learning. It receives glutamatergic input from sensory, motor, and associative brain regions, and incorporates reward information through phasic dopamine input. The glutamatergic input from cortex is hypothesised to provide the necessary efference copy of the performed/ongoing action, allowing assignment of credit to the relevant dimension of the action through synaptic plasticity at corticostriatal synapses. I will investigate how this mechanism unfolds in the corticostriatal network of the mouse. I have developed a novel head-fixed joystick task for mice, which enables selective reinforcing of specific dimensions of skilled forelimb actions. Using this task I will investigate if and how these dimensions of the action are represented in neural activity patterns of the corticostriatal circuitry during learning, how they emerge, and if separate subcircuits are needed to learn specific dimensions. Two distinct neuronal classes project from cortex to striatum, intratelencephalic (IT) and pyramidal tract (PT) neurons. I show that for mouse forelimb circuit, these cells are distributed across widespread cortical areas with specific distinctions in their locations. I will use a battery of neurogenetic tools to optically record and manipulate the activity of these neuronal populations while mice are learning and performing new forelimb actions. This will allow me to assign specific action dimensions to distinct cortical areas, cell-types, or activity patterns, and inform which cortical regions are involved in reselection and refinement of the action.Investigating action learning in a versatile but controlled task, I will be able to ask the fundamental question: which sensorimotor corticostriatal information is needed for which aspects of motor learning through reinforcement. These experiments will extend knowledge of motor control theory and pave the way for future studies on corticostriatal circuit function and dysfunction in disease.

StatusFinished
Effective start/end date1/1/196/30/20

Funding

  • Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung

ASJC Scopus Subject Areas

  • Genetics(clinical)
  • Neuropsychology and Physiological Psychology

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