Masmanidis Lab

  • Brain recording with processed data.
  • Silicon probe
  • lab logo saying "The M Lab"
  • Thalamostriatal projections
  • Dopaminergic reward signals
  • Mouse and graph showing experimental setup with optogenetics
  • Mouse gait
  • VTA dopaminergic neurons
  • Striatal PV cells

Joining the lab / Open positions

High school students: Unfortunately, we are unable to accept high school students. 

Graduate and Undergraduate Students: Please visit our Student Research Opportunities page for more information.

Postdoctoral scholars: Due to funding constraints we are only able to consider applicants with prior training grant success.

Research

The main goal of our lab is to better understand the neural basis of learning and movement. Our approach includes measuring and manipulating the neural dynamics of different brain areas and cell types. Some ongoing projects and relevant publications are outlined below. We are also starting to think about whether any of the concepts we use for studying brain circuit dynamics and function can be extended to understanding large language models underlying AI tools. Visit our AI Interpretability page for more information.

1. Dopaminergic and Striatal Roles in Reward Learning and Prediction.

The ability to associate specific sensory stimuli with rewarding events is one of the most essential and widely studied forms of learning since Pavlov's famous experiments. But, in many situations, animals need not only learn what reward they will get, but also when they will get it, allowing them to proactively prepare for reward consumption. We are investigating how dopaminergic and striatal circuits mediate the learning, execution, and timing of reward-conditioned movements.

Learning dynamically regulates stimulus discrimination of ventral striatal D1 receptor expressing neurons

  • Preprint examining how ventral striatal D1 and D2 spiny projection neurons distinguish between reward-paired and unpaired sensory cues, and how these stimulus discrimination properties evolve across learning.

The learning primacy hypothesis of dopamine: reconsidering dopamine’s dual functions

  • Review explaining our departure from the popular view that dopaminergic neurons serve important roles in both reinforcement learning and the performance of movements, two fundamentally distinct processes. Instead, we propose a comparatively limited dopaminergic contribution to movement (i.e., learning has primacy).

2. Neural Coding of Movement in Parkinson's Disease Models.

Impaired gait is a major and debilitating motor symptom in Parkinson's disease, for which the underlying mechanisms are not fully understood. We are investigating how basal ganglia activity representing locomotion and gait is altered in mouse models of Parkinson's disease.

Dopamine Lesions Alter the Striatal Encoding of Single-limb Gait

  • In this paper we examined the effect of dopamine loss on the encoding of locomotion and gait in striatal D1 and D2 spiny projection neurons.