Xiangmin Xu

My laboratory research has been focused on understanding the organization and function of neural circuits.  The research applies to understanding the neurobiology of sensory perception, learning and memory, and cognition.  

Our research addresses several major questions described below.

• How do laminar and cell-type specific connections govern neural signal transformations in sensory and higher-order cortical circuits?
• How are specific hippocampal neurons integrated in local and long-range circuits to regulate learning and memory?
• What are the defined contributions of specific cell types to network circuit activity and behavioral outcome?

We use a multidisciplinary approach that combines electrophysiology, photostimulation and optical imaging, molecular genetics and viral tracing to address circuit questions.  One direction is to look at circuit connections.  We map the relationship between different cell types in all levels of circuits, from global circuit levels to local and microcircuit levels.  It is important to map circuit connections to understand cortical function.  In the other direction, we are able to manipulate the circuits.  This is where we can test the connections and functions using new molecular tools that allow us to activate or inactivate particular elements of the circuits.  Our analysis is further refined and informed by engineering and computational techniques.  

These studies will increase our mechanistic understanding of neuronal circuit organization in the cerebral cortex.  This will guide future studies to assess and treat circuits in the brains that are altered following disease or injury.  The results of this research also will enable better therapeutic targeting of neuronal components disrupted by disease that contribute to perceptual disability, learning and memory disorders.