Research Projects

Project Summary Sequences of neuronal activity are thought to underlie planning, preparation, and production of voluntary skilled behaviors.

Project Summary How does the brain transform sensory information into complex behavior? The objective of this proposal is to identify the relevant neurons across the brain that are necessary to produce a relatively simple motivated behavior to study and identify fundamental principles underlying coding. Sensory-to-behavior circuits must contain a variety of neural computations such as those that determine the identity and meaning of the sensed cues, gauge internal state, remember previous experience, and command muscle action.

Project Summary Dopamine neurons (DNs) are key regulators of motivated behaviors, and defects in dopamine signaling may underlie some psychiatric disorders including addiction, depression, and schizophrenia, as well as neurological disorders such as Parkinson's. Much of the work in this area has been based on the dogma that DNs encode reward prediction errors (RPE) and that they do so in a uniform manner. However, work from several groups, including ours, indicates that DNs projecting to different targets exhibit distinct properties and serve distinct functions.

Cortical Signature and Modulation of Pain Abstract/Project Summary Pain perception contains two main dimensions: the sensory-discriminative and the affective-cognitive aspects. In this proposal, we will focus on the cortical signature and modulations of the sensory aspects of pain using mouse models. Pain can be largely divided into inflammatory or neuropathic pain. A common condition in both types of pain is mechanical allodynia: externally applied innocuous gentle touch becomes painful.

Project Summary Two of the most fundamental questions of sensory neuroscience are: 1) how is stimulus information represented by the activity of populations of neurons at different levels of information processing? and 2) what features of this activity are read at the next levels of neural processing to guide behavior? The first question has been the subject of a large body of work across different sensory stimuli. To answer the second question, one needs to establish a causal link between neuronal activity and behavior.

PROJECT SUMMARY Sensory perception involves processing incoming sensory input and interpreting that information through rules generated from prior experience. Stimulus features need to be bound together to form more complex sensory representations and then associated with a valence or action outcome to give meaning to those representations. In the mammalian neocortex, the formation of sensory representations is believed to occur through processing that is distributed across several cortical areas.

Sensory processing is a way to understand neural circuits and their functions during behavior. Behavioral context strongly affects sensory processing. For example, a brief visual stimulus is easier to detect if it appears in a predictable spatial location. Attention to visual space strongly enhances neural and behavioral responses to stimuli in those locations, but the detailed neural mechanisms producing these effects remain unknown.

PROJECT SUMMARY We seek to better understand how the brain processes olfactory information by focusing on how circuits of the olfactory bulb control two fundamental aspects of sensory processing: the relationship between sensory input and olfactory bulb output as a function of stimulus intensity, and tuning of response specificity by lateral inhibition.

Abstract Motion detection, a fundamental computation of the visual system, begins in the retina. In the mammalian retina, the direction of moving objects is computed by the direction-selective circuit. The retinal output of this circuit is provided by direction-selective ganglion cells (DSGCs). These cells are strongly activated by motion in their preferred direction, but are suppressed by motion in the opposite, or “null”, direction.

Functional interactions between the entorhinal cortex and hippocampus are critical for spatial navigation and episodic memories related to people, places, objects and events. Canonically, medial entorhinal cortex (MEC) processes spatial information while lateral entorhinal cortex (LEC) processes non-spatial contextual information.