The lab uses multiple animal models to understand how the architecture and function of sensory system meets the behavioral demands of the animal , which are majorly shaped by the body and its movements.  One of our main goals is to understand how neural circuits transform the visual signals that arrive at the retina into information used by downstream circuits to 'see' and to 'act'. Our other main goal is to understand how the information encoded in visual circuits is shaped by an animal's particular movements. This understanding is pivotal to discovering how visuomotor circuits become optimized to the unique demands of individual animals, including humans. We use in vivo two-photon imaging, electrophysiology, high-throughput behavioral monitoring and mathematical modeling to understand the structure and function of visual circuits, and how they are shaped by bodily movements. In a subset of projects, we use sensors worn by the animal to record the actual environmental inputs that the various biological sensors, like the eye, receive during natural behaviors. We take advantage of recent progress in behavioral quantification techniques to understand how sensory inputs differ during different movement behaviors, and how the brain takes advantage of these differences. Our work will contribute to understanding sensory processing in a manner more faithful to our experience as moving animals. 

Rats and tree shrews, who move and see differently, will serve as our model organisms. ​Rats are about the size of a tree shrew, so using them instead of mice reduces some confounds related to brain and body size, but preserves the advantage that mice offer regarding how much we already know about the visuomotor circuits and behaviors. Other than size, tree shrews are pretty different from rats. They're something between a squirrel, a monkey, and a rodent. Evolutionarily, they are the closest living relative of primates. Most importantly for our lab, they are visual and movement specialists! However, we know relatively little about their viusomotor system and behavior, so there is a lot to discover!  Also, fun fact: they have the highest encephalization quotient (brain to body mass ratio) of any mammal. A comparative approach across species with different visual abilities and movement patterns gives us the amazing ability to leverage evolution to understand how behavioral demands influence the structure and function of the sensory system. 

Projects

• Encoding of self and externally generated visual information in the visual system of the tree shrew (2P imaging and/or electrophysiology in awake head-fixed animals, viral tracing to map circuit pathways)
• Encoding of self-generated visual and non-visual information in the visuomotor system of freely moving animals (wireless electrophysiology, behavioral monitoring)
• Statistical properties of visual inputs during natural, and trained, behaviors (large-scale data analysis and computational modeling)

Relevant Publications

Full publication list here

• A sinusoidal transformation of the visual field is the basis for periodic maps in area V2 (2021).  This is the first study on the secondary visual cortex (V2) of tree shrews. We found that the neuronal populations transforms the visual environment in a complex but mathematically tractable way that may explain previously puzzling findings in V2 of squirrels, cats, and primates. This study made me an expert in in vivo two photon imaging in awake tree shrews and made me appreciate the value of a good model organism in resolving confusing data. Many other visual areas in the tree shrew beyond V2 are still completely uncharted, and could reveal similarly useful surprises (Project 1 above).
• What & Where: Location-dependent feature sensitivity as a canonical organizing principle of the visual system (2022).  This is a review/opinion paper I wrote with David Fitzpatrick. It makes the argument that the visual system is organized around statistical regularities in the sensory environment of the animal, and that its important to understand these regularities by measuring them from the animal's point of view. This is a less technical read for some of the topics that lab cares about.
• In vivo dynamics of thalamocortical synapses in visual cortex (2017). This is a study on how visual inputs are transformed along the visual pathway of the cat's brain. We recorded with extracellular electrophysiology in the visual thalamus, and simultaneously with intracellular electrophysiology in the input layers of visual cortex. This allowed us to find pairs of cells likely to be connected, which then allowed us to map out how the architecture of this pathway leads to the emergence of orientation selectivity from the visual thalamus (where it's weak) to the visual cortex (where it is very robust). This study gave me expertise in a very difficult electrophysiology technique and gave me some insight into cross-species differences. 
  
• Hippocampal theta oscillations precede seizure onset in a model of temporal lobe epilepsy (2014).  This is a study from my doctoral work in an Engineering department. The paper highlights our findings that certain brain rhythms can be used to predict epileptic seizure onsets in rats experiencing a particular type of epilepsy originating from the temporal lobe. What is not highlighted in the paper, but was instrumental in developing my research direction, is all the work we did to record brain and bodily activity from freely moving animals 24-7, as well as the work it took to analyze and model that data. This study gave me experience with collection of large-scale datasets from naturally behaving animals and made me appreciate just how useful such datasets can be in demystifying brain activity and architecture.