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• Axon guidance during habenular commissure formation
• Functions of the habenula

Research Projects

We use the zebrafish to address fundamental questions in neuroscience. One project in the lab relates to the formation of neural circuits. In the embryo, neurons extend axons that are guided to their final targets by a series of guideposts or intermediate targets. Growth cones are first attracted to these guideposts, but must then leave them. We are investigating how growth cone responsiveness is altered at intermediate targets.

The best studied intermediate target is the embryonic midline. We focus on midline crossing in the habenula, which is in the dorsal forebrain. This system has several advantages: mutants are available, high resolution live-imaging is possible and commissural neurons can be manipulated by electroporation. We can also culture the neurons for in vitro assays.

We have identified a gene required for formation of the commissure, and are using this as a starting point to investigate how various cellular processes are integrated to enable the change of state necessary for midline crossing.

The habenula is found in all vertebrates, and is a component of the pathway for information flow from the limbic forebrain to the midbrain. We have identified afferent neurons and are interested in the function of this neural circuit. Recent studies have implicated the lateral habenula in reward anticipation in mammals, while earlier work has suggested an involvement in fear responses.

Fear is the subject of the second major project in the lab. We focus on the response of fish to Schreckstoff, which is the alarm pheromone contained within specialized cells in the skin. When the skin is broken, the pheromone is released, triggering a rapid change in the swimming behavior of fish. We are defining the neural circuit involved in this response.