Title: Modulation of fear behavior via transgenic and optical disruption of neural activity in the zebrafish habenula
Date/Time: 14 Sept 2010 (Tuesday), 4pm
Venue: AS7/01-17 (Seminar Room B)
Animals learn to fear stimuli that predict danger, and quickly acquire defensive responses to those threats. However, pre-exposure to uncontrollable aversive events produce a helpless state that impairs subsequent active avoidance learning, accompanied by a cascade of stress-induced neural activation in brainstem nuclei. Lesion experiments in rodents have implicated the habenula, a node in information flow to the midbrain, in the mediation of appropriate avoidance behavior. However, while some reported that habenula lesions produce avoidance deficits, others have found that the lesions reduce the avoidance deficits caused by inescapable shock. To clarify the role of the habenula, we developed an assay for fear conditioning in juvenile zebrafish, whose transparency and amenability to genetic manipulation enables precise manipulation of neural circuits. We show that juvenile zebrafish learn to avoid a predictable electric shock when it is escapable, but fail to do so when pre-exposed to inescapable shock. Perturbation of specific habenula neurons leads to a similar failure in avoidance. Our findings identify components of the neural network regulating fear responses in vertebrates, and suggest a pathway that provides signal for control over a stressor. Disruption of these neurons and consequent dysregulation of monoaminergic systems may contribute to pathological conditions associated with anxiety disorders.
About the speaker:
I am interested in the neuroscience of learning, specifically, stress and reward anticipation. My research currently involves behavioral quantification and bioimaging of the zebrafish as I work to uncover activity and timing processes of the neural correlates underlying the animal’s learning capacity.