Our work determines how electrical activity flows in circuits of neurons during sensory perception and motor behaviors.
We focus these investigations in the mouse cerebral cortex. The mouse cortex shares many of the same basic components and circuits as the human cortex. However, the small size, ease of access, and behavioral repertoire of mice offer many experimental advantages. Moreover, by utilizing genetically engineered mice, we are able to manipulate and record activity from specific types of neurons during learned behaviors.
We perform electrophysiological recordings while mice view and process visual stimuli that guide their actions. During this process, we record synaptic inputs and action potential outputs from individual neurons, and also record population activity across large-scale neural networks.
Our endeavor is to link two research themes: modulation of neural networks by behavior, and network modulation of single-neuron synaptic activity.
Our work serves as a unique entry point to investigate both neural circuits and biophysical mechanisms underlying normal and dysfunctional behaviors.
Finally, our research offers significant collaborative opportunities to modify, improve, and implement novel technologies for manipulation and recording of neuronal activity during behavior.
We have three main topics of investigation:
- Inhibitory circuits | We have shown that inhibitory circuits powerfully control the spatial and temporal extent of sensory signals in the awake cortex. Using optically targeted recording and manipulation of inhibitory interneurons, we aim to delineate how inhibitory circuits are flexibly recruited by behavioral context.
- Excitatory circuits | The great majority of neurons in the cerebral cortex are excitatory. These are further divided into many sub-types. We showed that these excitatory neuron sub-types respond uniquely to complex sensory stimulation. The factors underlying this functional diversity are largely unknown. We will determine the mechanisms underlying sensory processing in excitatory neuron sub-types.
- Ongoing cortical activity | The cerebral cortex is constantly active. Much of this activity is rhythmic, across many time-scales. We have identified mechanisms that diminish or enhance sensory perception at both slow (seconds) and fast (millisecond) time-scales. We will determine how this slow and fast variability of cortical rhythms relates to ongoing variations of sensory processing and behavioral performance.
Neurons respond to the external world with internal bioelectrical signals. Our lab specializes in electrophysiological recording of these signals in vivo during behavior. To do this, we utilize whole-cell patch-clamp recordings from individual neurons, and record their synaptic inputs as well as their action potential outputs. We also record action potentials from tens to hundreds of individual neurons simultaneously using high-density multi-site silicon electrodes. These combined techniques allow multiple levels of investigation: from single neuron biophysics to large-scale network interactions.
In combination with advanced microscopy and optics, our recordings can be targeted to genetically defined neuron types that express fluorescent proteins or optically excitable ion channels. This enables precise knowledge of the neurons we record from. Finally, we monitor this neuronal activity simultaneously with ongoing behavioral metrics, such as successful or unsuccessful movements to obtain rewards.
We rely on computational analysis and simple modeling to relate these electrical signals to each other, and to detail their relationship to sensory and behavioral events. We have a history of fruitful collaboration with computational and theoretical colleagues in these efforts.