News Release

Singapore scientists discover a possible off-switch for anxiety

Breakthrough sheds light on poorly understood region of the brain

Peer-Reviewed Publication

Agency for Science, Technology and Research (A*STAR), Singapore

Scientists from the Agency of Science, Technology and Research/Duke-NUS Neuroscience Research Partnership (A*STAR/Duke-NUS NRP), A*STAR's Institute of Molecular and Cell Biology, and the National University of Singapore have made a breakthrough concerning how anxiety is regulated in the vertebrate brain. Their work, published in the journal Current Biology, sheds light on how the brain normally shuts off anxiety and also establishes the relevance of zebrafish as a model for human psychiatric disorders.

The team of scientists, led by Dr Suresh Jesuthasan from the A*STAR/Duke-NUS NRP, showed that disrupting a specific set of neurons in the habenula[1] prevents normal response to stressful situations. In their experiments, Dr Jesuthasan's team trained larval zebrafish to swim away from a light in order to avoid a mild electric shock. While normal fish easily learned this task, fish that had a specific set of neurons in the habenula damaged displayed signs of "helplessness". Although they initially tried to avoid the shock, they soon gave up. What's more, these fish showed indications that they were more anxious than normal fish, such as being startled easily by non-harmful stimuli. Because of the similarity of the zebrafish[2] brain to the mammalian brain, the study suggests that malfunction of the habenula is a possible cause of certain anxiety disorders in humans. This means that it may be possible to use direct stimulation of the habenula as a way of treating some types of anxiety disorders in humans. The zebrafish model which the scientists developed in the course of their work may also be used in future drug discovery efforts for psychiatric medicines.

Said Dr Jesuthasan, "Our work deals with fundamental aspects of human experience – stress and anxiety. We think that the habenula of the brain is associated with the assessment of whether a stress has been overcome. Our study provides one possible explanation as to why the need to control the environment is such a critical component of human behavior – the feeling of control enables organisms to deal with stress."

Prof Dale Purves, Program Director of the Neurosciences and Behavioral Disorders Program at Duke-NUS Graduate Medical School and Executive Director of theA*STAR-Duke-NUS NRP, commented, "It may seem strange to be exploring anxiety in a tiny fish, but the advantages of animal models like this for understanding complex human disorders may well be our best bet. This important work by Dr. Jesuthasan and his colleagues is a first rate example of this."

Dr Jesuthasan and his team plan on continuing their studies of the habenula in humans and are also exploring how they can use their knowledge of habenula function to treat anxiety disorders.

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Agency for Science, Technology and Research (A*STAR)

For more information, please contact:
Joshua Tan (Mr)
Corporate Communications
Agency for Science, Technology and Research (A*STAR)
Tel: (65) 6826 6353
Email: joshua_tan@a-star.edu.sg

About the A*STAR - Duke-NUS Graduate Medical School Neuroscience Research Partnership (NRP)

The A*STAR-Duke-NUS NRP, forged in October 2007, aims to establish an integrated, multidisciplinary programme in neuroscience with a strong focus on translational research. This partnership will capitalise on the complementary research strengths and resources available within the A*STAR research institutes and the Duke-NUS Neuroscience and Behavioural Disorders (NBD) Signature Research Programme.

About the Agency for Science, Technology and Research (A*STAR)

The Agency for Science, Technology and Research (A*STAR) is the lead agency for fostering world-class scientific research and talent for a vibrant knowledge-based and innovation-driven Singapore. A*STAR oversees 14 biomedical sciences, and physical sciences and engineering research institutes, and seven consortia & centres, which are located in Biopolis and Fusionopolis, as well as their immediate vicinity.

A*STAR supports Singapore's key economic clusters by providing intellectual, human and industrial capital to its partners in industry. It also supports extramural research in the universities, hospitals, research centres, and with other local and international partners.

For more information about A*STAR, please visit www.a-star.edu.sg.

[1] The habenula has been shown to be involved in many functions of the brain, such as pain processing, reproductive behavior, and learning. It also seems to be involved in reward processing, particularly with respect to negative/adverse feedback.

[2] The habenula is difficult to study in humans and in other mammals because it is located deep in the brain. However, the habenula in the zebrafish is located located near the surface of its brain, and is thus easily accessible for study.


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