RESEARCH

The major focus of my research program is the development and plasticity of the central nervous system. Our model is the olfactory system of zebrafish, a common laboratory model for molecular genetics. The olfactory system is unique in that it is a continually developing sensory system. Throughout life, new neurons are born and new connections are made both in the nose and in the olfactory bulb of the brain.
One of the main areas of research in my lab is an examination of the process of neurogenesis in the olfactory bulbs. New cells are generated in the adult zebrafish brain, and many of those cells are found in the olfactory bulbs. The photo to the left shows a newly generated cell (in red) that does not label with a neuronal marker (in green). I am currently characterizing the newly formed cells and intend to examine their birth, migration, and differentiation.
Another area of my research is an analysis of how peripheral olfactory structures affect the maintenance of their central target in the brain. I am investigating the changes in activity levels, gene and protein expression, and cellular morphology following peripheral olfactory deafferentation of the olfactory bulbs. The photo to the left is a section through the olfactory bulbs (ob) of a fish that had the right olfactory organ ablated (*); the right olfactory organ (oe)remains intact. The figure on the right shows labeling for a specific protein (tyrosine hydroxylase) in the olfactory bulbs of a deafferented fish; note that the labeling on the operated right side is diminished.
We aim to elucidate some of the cellular interactions and molecular factors that are responsible for these phenomena. This research has important implications for neural regeneration and recovery from brain injury and disease.
We use a variety of techniques in this research including the following:
Immunocytochemistry
In situ hybridization
General histological methods
Brightfield and fluorescence microscopy
Confocal microscopy
Electron microscopy
Microdissection and animal surgery
Neuronal tract-tracing
Figure 1 - This is a plastic section through the zebrafish "nose", the olfactory rosette. This beautiful structure houses the olfactory neurons that send the odorant information to the brain.
Figure 2 - Photomicrograph of the olfactory bulb, the brain region that processes information from the sense of smell, from a zebrafish. This section has been stained with an antibody to BrdU, a thymidine analog that is used to label newly formed cells. The darkly stained cells are cells that divided and formed in the adult animal, supporting the evidence from other animals that new cells can be aded to the adult brain.
Figure 3 - We are currently using techniques such as immunohistochemistry to determine what cell types are formed in the adult bulb. This photomicrograph illustrates the distribution of tyrosine hydroxylase, an enzyme important in the formation of certain neurochemicals and known to be present in specific neuronal populations.