Research Interests

The goal of our research is to understand how the architectures and functional operations of neuronal circuits give rise to conscious perception in the mammalian brain. During conscious perception, our brain actively interprets the sensory data based on internal brain states, such as prior experiences, expectations and attention. Such internal modulation is implemented through long-range feedback and neuromodulatory projections, which crucially influences how we adaptively and dynamically perceive the world. Our laboratory is interested in understanding the underlying neuronal circuits and biophysical mechanisms of the internal modulation during perceptual behavior. Currently using mouse auditory system as the model system, we focus on the following questions:
  1. How does internal modulation impact auditory perception at the behavior level?
  2. What are the neural substrate (circuits and neural codes) of internal modulation?
  3. At the cellular and circuit level, how does internal modulation interact with sensory input and influence perceptual decisions during well-defined perceptual tasks?
We use innovative optical and electrophysiological methods, including in vivo two-photon imaging and multi-channel probes, to record detailed neuronal activity at subcellular resolution in the neocortex and deep brain regions of head-fixed mice performing two-choice decision-making tasks. We have established the methods to image calcium signals in population neurons, dendritic branches, and axonal terminals in defined neural circuits in task performing mice. Combining advanced imaging techniques with specific circuit manipulation and quantitative behavior, we have uncovered a dendritic computation mechanism in sensory cortex in active tactile perception (Xu et al, Nature 2012), the causal role of cortical circuits involving the posterior parietal cortex (PPC) and auditory cortex in decision-making and categorization (Zhong et al, Nature Neuroscience 2019), a cortical computational mechanism in the auditory cortex for stimulus categorization (Xin, et al, Neuron 2019). These approaches allow us to  tackle challenging problems in neuroscience, uncover circuit mechanisms underlying fundamental cognition, and ultimately help understanding the fundamental neuronal mechanisms that govern our conscious perception.