Yunming Wu

Yu Lab

Postnatal development of olfactory map formation

OSN axons genetically labeled with GFP converge into a glomerulus.

In the developing brain, sensory neurons respond to experience of environmental stimuli with dramatic changes in their anatomical connections. A well-known example is the critical period in the visual system demonstrated by Hubel and Wiesel. Deprivation of neural activity in the sensory neuron in early postnatal period leads to changes in the receptive field in the thalamus and in the cortex.

The olfactory sensory neurons (OSN) are unique in that they have a continuous regeneration capability and have stereotypical connections into the olfactory bulb (OB), the primary relay center for olfactory information in the brain.  In the olfactory epithelium, each OSN expresses one of the ~1300 olfactory receptors. Each glomerulus in the OB receives convergent axon input originating from neurons expressing the same type of odorant receptor.  The convergence of neurons expressing different receptor types onto different glomeruli forms a spatial map. During the life span of an animal, newly generated OSNs continue to make the precise connections and maintain this accurate map.  It is a mystery as to how the continuous generating neurons target the same glomerulus accurately.

This image depicts the mitral cell, secondary neuron receiving input from OSNs.

My research focuses on the developmental plasticity of OSN axon guidance.  My goal is to identify the molecular and cellular mechanisms responsible for the precise targeting of axons during the postnatal developmental period. In my thesis I use genetically engineered mice to manipulate the neural activity and utilize classical histology with the genetic labeling technique to visualize the behavior of the OSNs during the postnatal development. This work will help to further understand the mechanism of neurogenesis and circuit connection in the developing and adult brain.