The Turner lab is using genetic and optogenetic models to study the function of a poorly understood brain region, the medial habenula. In these experments we have used a developmental lesions to ablate subsets of habenula neurons, and we have expressed optogenetic channels in the habenula to allow control of neural activity with light.
A circuit through an adjacent structure, the lateral habenula, has recently been shown to mediate “negative reward” or “punishment” signals, by modulating dopamine release from the ventral tegmental area. The anatomical circuitry of the medial habenula does not support this specific role. However, a diverse collection of studies suggests that some part of the habenula structure may mediate a reward signal. We are using a variety of reward paradigms to test the function of genetically defined populations of medial habenula neurons in reward.