Cortical neurons represent sensory and motor features. What circuit mechanisms shape cortical coding? Which neurons drive behavior? Our lab addresses these questions using optical approaches in head fixed mice.
By combining carefully designed behavioral assays with advanced optical techniques, we hope to determine the minimal subset of neurons whose perturbation can impact behavior.
In sensory cortex, neurons with common tuning are more interconnected than neurons with distinct tuning. We are probing how such connectivity enables computations like amplification, pattern completion, and feature detection.
Our experiments depend on rapid turnaround of terabyte-scale datasets. We are developing pipelines to process data acquired during calcium imaging and behavioral videography, and to relate neural activity to behavior.
Approaches such as high speed videography and image processing allow precise measurements of the behavioral state of the animal. Tasks are designed so that even subtle changes in the animal's behavior can be detected.
Two-photon microscopy using modern calcium indicators allows us to record the activity of thousands of cortical neurons during behavior. Neurons can be tracked over months, and structural indicators can label cell types.
A prerequisite to exploring the behavioral roles of neurons is understanding the spatial distribution of functional neural types. We are actively generating mesoscale maps of cortex during behavior, on the 10K-100K neuron scale.
Neurons encoding particular features are often intermingled with other neuron types. Approaches like multiphoton ablation and two-photon optogenetics allow for lesioning and activation with cellular precision, making it possible to target intermingled populations.
Peron SP, Pancholi R, Voelcker B, Wittenbach JD, Olafsdottier FH, Freeman J, Svoboda K
Peron SP, Chen TW, Svoboda K
2015, Curr. Opinion Neurobiology
Peron SP, Freeman J, Iyer V, Guo C, Svoboda K
Huber D, Gutnisky DA, Peron SP, O'Connor DH, Wiegert JS, Tian L, Oertner TG, Looger LL, Svoboda K
Peron SP, Svoboda K
2011, Nature Methods (outlook)
O'Connor DH, Peron SP, Huber D, Svoboda K
Simon earned his PhD with Fabrizio Gabbiani at Baylor College of Medicine, studying single neuron computation in the context of insect vision. He did his postdoctoral work with Karel Svoboda at Janelia Farm, working on mechanisms of cortical processing in the behaving mouse using two-photon microscopy.
Ravi joined the lab in 2018 and is studying how optogenetic microstimulation of barrel cortex drives cortical plasticity and perception.
Tina joined the lab in 2018 and is studying how vibrissal sensory representations arise from network interactions in L4-L2.
Lauren joined the lab in 2019 and is studying the role of vibrissal cortex in behavior using a barrel-scale laser lesion approach she developed.
Since the discovery of complex and simple cells by Hubel and Wiesel in visual cortex, neuroscientists have sought to understand the circuit mechanisms that give rise to specific receptive fields in sensory cortex. In barrel cortex, receptive field complexity increases from L4 to L2: neurons that respond to a single direction of touch for one whisker become rarer, while neurons that either respond to both directions or multiple whiskers become more frequent. We have an NIH-funded project (NINDS R01 NS117536) to study how local circuit interactions between various cell classes contribute to receptive field structure. This project combines in vivo behavior, volumetric calcium imaging, and cellular resolution perturbation techniques like multiphoton ablation and two-photon optogenetics to tease apart the way in which local circuits transform receptive fields in primary sensory cortex, and how these interactions influence perception.
Understanding how circuit interactions drive perception is a central goal of systems neuroscience. We recently developed an all-optical approach to address this question, combining one-photon optical microstimulation with volumetric calcium imaging to study how cortex changes as it is exposed to a novel perceptually-relevant activation pattern. This project will ask, first, how deviations from the trained activity pattern influence perception - that is, how do factors like timing and neuron identity impact perceptual readout. Second, we seek to understand the rules governing how changes in cortical activity drive reorgnization of the underlying cortical network.