Associate Prof Suresh Jeyaraj Jesuthasan

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Associate Professor Suresh Jeyaraj Jesuthasan

D. Phil.
Associate Professor of Behavioural Neurosciences
Email: sureshj@ntu.edu.sg
Principal Investigator, Brain States and Behaviour Laboratory






Laboratory Staff

  • Dr. Ruey-Kuang Cheng, PhD, Research Fellow
  • Gadisti Aisha Nurulhijjah Binti Mohamed, Research Associate
  • Kathleen Cheow Wen Bei, Research Assistant
  • Joanne Chia, Graduate Student
  • Mahathi Ramaswamy, Graduate Student
  • Seetha Krishnan, Graduate Student

 

Introduction

Associate Professor Jesuthasan is Associate Professor of Behavioural Neuroscience in Lee Kong Chian School of Medicine, Nanyang Technological University. Prior to this appointment, Assoc Prof Jesuthasan worked at the Institute of Molecular and Cell Biology in Singapore, and the Duke-NUS Graduate Medical School. He obtained an undergraduate degree in Electrical Engineering at Stanford University, and a DPhil in Developmental Biology under the guidance of Julian Lewis at Oxford University. He has worked  at the Max Planck Institute for Developmental Biology in Germany, in the laboratory of Friedrich Bonhoeffer.
Assoc Prof Jesuthasan is internationally recognised for his contributions to the area of early embryonic development, where he provided fundamental insights into symmetry breaking and cell division in the early zebrafish embryo. He is also known for his work on fear triggered by an alarm pheromone in fish, and on how brain states are regulated. His current work on the control of neuromodulators is relevant to mood and neurological disorders.

Research Focus
Brain State and Behavior

An animal’s survival depends on its ability to react appropriately to environmental stimuli. The responses can be innate, but can also be modified by experience and internal state (e.g. hunger and time of day). The goal of the lab is to gain insight into how the vertebrate brain generates an optimal response. To do this,  Assoc Prof Jesuthasan  and his teamuse a combination of anatomy, high-resolution functional imaging, genetics, behavioral assays and modelling. Behavior is generated by neural circuits. Connectivity between circuit components is not fixed, but is dynamically regulated by neuromodulators. The major question they are interested in, thus, is how neuromodulator release is controlled based on sensory stimuli and internal states.
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The Alarm Response

A starting point for experiments is the alarm response. In the 1930’s Karl von Frisch noticed that injury to a European minnow caused a fright reaction in other members of the fish school. He demonstrated that the skin contains substances, termed Schreckstoff, which act via the olfactory system to trigger a state of fear. The fish change their swimming behavior dramatically - either darting or freezing - in response to this alarm pheromone. Subsequent experiments by other scientists established that many freshwater fish species have this response. All the classical hallmarks of fear, including physiological changes such as increase in blood cortisol levels, can be triggered by Schreckstoff. They used classical biochemical separation to characterise the alarm substance, and showed that it consists of glycans. Current experiments are focused on characterising the higher brain regions involved in the response, either by calcium or voltage imaging. One region of interest is the habenula.
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The habenula
The habenula is an evolutionarily conserved structure that regulates neuromodulator release. It is well placed to control functional connectivity in response to a wide range of variables, as it receives input from all sensory systems, including the olfactory system, and receives reward information from the basal ganglia. Information from the circadian clock is also channeled to the habenula. They are able to image activity in all cells in the habenula. In addition, neural activity can be manipulated either optically or by expression of tetanus toxin. They are currently investigating how information is processed in the habenula, and also looking at the potential involvement of the habenula in a number of diseases associated with abnormal neuromodulator control, e.g. mood disorders.
 
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Key Publications
  1. R-K Cheng, S. Krishnan, S. Jesuthasan (2016). Activation and inhibition of tph2 serotonergic neurons operate in tandem to influence larval zebrafish preference for light over darkness. Scientific Reports, 6:20788.
  2. S. Krishnan,  A. S. Mathuru, C. E. Lupton, C. Kibat, M. Rahman, J. Stewart, A. Claridge-Chang, S.-C. Yen, and S. Jesuthasan (2014). The right dorsal habenula limits attraction to an odor in zebrafish. Current Biology. doi:10.1016/j.cub.2014.03.073.
  3. A. Mathuru and S. Jesuthasan (2013) The medial habenula as a regulator of anxiety in adult zebrafish, Front. Neural Circuits, doi: 10.3389/fncir.2013.00099
  4. A. Mathuru, C. Kibat, W. F. Cheong, G. Shui, M. R. Wenk, R. W. Friedrich and S. Jesuthasan (2012) Chondroitin fragments are odorants that trigger fear behavior in fish. Current Biology, 10.1016/j.cub.2012.01.061.
  5. A. Lee. A. Mathuru, C. Teh, C. Kibat, V. Korzh, T. Penney and S. Jesuthasan (2010) The habenula prevents helpless behavior in larval zebrafish. Current Biology, 20: 2211-2216.
  6. J. D’Souza, M. Hendricks, S. Le Guyader, S. Subburaju, B. Grunewald, K. Scholich and S. Jesuthasan (2005), Formation of the retinotectal projection requires Esrom, an ortholog of PAM (protein associated with Myc), Development; doi: 10.1242/dev.01578.
  7. B. Feng, H. Schwarz and S. Jesuthasan (2002), Furrow-specific endocytosis during cytokinesis of zebrafish blastomeres. Exp. Cell Res., 279,14-20.
  8. S. Jesuthasan (1998), Furrow-associated microtubule arrays are required for the compaction of zebrafish blastomeres following cytokinesis, J. Cell Sci, 121, 3695-3703.
  9. S. Jesuthasan and U. Strähle (1997), Dynamic microtubules and specification of the zebrafish embryonic axis, Current Biology, 7, 31-42.
  10. S. Jesuthasan (1996) Contact inhibition / collapse and pathfinding of neural crest cells in the zebrafish trunk, Development, 122, 381-389.