Our lab is broadly interested in the dynamics of basal ganglia and other neural circuits that mediate learning and movement. Some ongoing and recently completed projects are outlined below.
Dynamics of cortical and striatal circuits:
Our signature technology is a silicon microprobe for recording the electrophysiological activity of large neural populations.
We rely on these tools to study the dynamics of cortical and basal ganglia circuits in behaving mice. Most of our work is carried out in mice trained on Pavlovian reward conditioning tasks, but we also work with operant tasks.
Lab members learn how to perform experiments with these recording tools (as well as complementary methods such as optogenetics and fiber photometry), and analyze data to examine dynamics and information processing in
different cell types and brain regions. In addition to studying what information is encoded by neural dynamics, we are interested in how dynamics of neural populations in the striatum are generated as a result of various local and external inputs.
To address this we combine neural recordings with optogenetic perturbations. These efforts allow frequent interactions with a vibrant community of UCLA researchers interested in computational and systems-level neuroscience. These are some relevant publications:
Here we collaborated with Dean Buonomano to study the temporal processing properties of corticostriatal network dynamics.
Here we evaluated the role of parvalbumin-expressing striatum interneurons on projection neuron activity and behavior.
Here we examined how striatal dynamics are shaped by excitatory input from cortex and thalamus.
Function of dopaminergic circuits in associative learning and movement:
Dopaminergic circuits play an unquestionably important role in behavior, but there is longstanding and vigorous disagreement about precisely what these functions are. Previously, our lab sought to clarify some of these functions by testing central predictions about
the effect of manipulating dopaminergic activity on behavior or neural activity. So far, our results suggest that dopaminergic neurons primarily play a role in learning about reward-based associations and a comparatively smaller role in the online production of movements - at least in the context
of certain Pavlovian responses. Additionally, we carried out electrophysiological measurements which place important constraints on how much dopaminergic neurons can rapidly modulate striatal circuit dynamics under physiological conditions. These are some relevant publications:
Here we compared the contribution of dopaminergic neurons to associative learning versus online movement generation.
Here is a preprint describing a project to systematically examine how striatal dynamics are shaped by physiological-range and potentially supra-physiological dopaminergic neuron input.
Here we collaborated with Anne Andrews to show that stimulating VTA dopaminergic neurons leads to co-release of serotonin in the nucleus accumbens.
Altered neural dynamics in brain disorder models:
We are interested in using electrophysiological recordings to identify altered patterns of neural activity in models of disorders such as addiction,
Parkinson's, and Huntington's disease. This is a highly collaborative effort, relying on frequent interactions with other labs at UCLA with expertise in brain disorder models.
These are some relevant publications:
Here is a review on the main ways in which neural activity in the striatum is altered in models of Parkinson's disease.
Here we collaborated with Mike Levine to study thalamocortical processing in a model of Huntington's disease.