Masmanidis Lab

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

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.

1. Dopaminergic and Striatal Roles in Reward Conditioning.

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.

Constraints on the Subsecond Modulation of Striatal Dynamics by Physiological Dopamine Signaling

  • Study examining how striatal dynamics are shaped by different levels of dopaminergic neuron input.

Temporally Restricted Dopaminergic Control of Reward-Conditioned Movements

  • Study comparing the contribution of dopaminergic neurons to associative learning versus online movement generation.

2. Comparing Neural Codes for Movement and Time Across the Brain.

The ability to produce well-timed movements is a fundamental aspect of brain function. While many brain areas are implicated in movement and timing, our understanding of the distinct contributions of different areas remains limited. We are using multi-region neural recordings to compare how the striatum and cortex represent various behavioral measures of movement and elapsed time. This effort involves frequent collaboration with the laboratory of Dean Buonomano.

Neural Sequences as an Optimal Dynamical Regime for the Readout of Time

  • Study looking at how the quality of neural sequences compares between the striatum and secondary motor cortex, and how these sequences can be used to read out time.

Differential Encoding of Time by Prefrontal and Striatal Network Dynamics

  • Here we compared the ability to decode elapsed time using population dynamics from the striatum and orbitofrontal cortex.

3. Altered 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.