Please tell us about yourself
Meet Aalok Varma of the National Centre for Biological Sciences (NCBS) in Bangalore, India. Aalok is a second year graduate student, a member of Vatsala Thirumalai’s Neural Circuits and Development Lab.
“Hi, I’m Aalok, from India. I did a B.Sc. in Biotechnology, and am currently a PhD student at NCBS, Bangalore, studying neuroscience.”
What are your research interests? What are you working on?
My lab works on understanding how the nervous system controls movement and how these systems develop, using zebrafish as our model organism. My own project in the lab is about understanding the contribution of different synapse types to behavior and development.
Please tell us about your work
For most animal species, survival depends critically on the ability to move- be it for feeding, escaping predators or selecting a suitable mate. To generate movement, skeletal muscles need to be contracted in precisely coordinated patterns. Neural circuits control the spatial and temporal pattern of skeletal muscle contractions. Our lab is interested in understanding the hierarchy, mechanisms and development of neural circuits that generate movement.
In vertebrates, the circuits that control movement are found in the spinal cord and in the brain. The spinal circuits controlling the generation of locomotion are referred to as ‘central pattern generators’ as the output from these circuits is patterned and rhythmic electrical activity sent to the muscles. These central pattern generators are in turn controlled by sensory drive and by commands from the locomotory centers of the brain.
My lab focuses on the development of central pattern generators and the development of descending motor control from the brain. We also seek to understand the mechanisms by which brain locomotor circuits control movement in mature organisms.
We use zebrafish, a small fresh water tropical fish endemic to the Ganges, as our model system. The embryonic and larval stages of these fish are transparent allowing for direct visual observation of developing internal organs including the brain. We employ a suite of techniques to tease out the circuitry responsible for generating swimming in developing and more mature zebrafish.
We record electrical activity from individual spinal and brain neurons using extracellular and whole-cell patch clamp techniques. We record activity from populations of neurons simultaneously using calcium imaging. We generate transgenic zebrafish to express proteins of interest in particular neurons. This allows us to selectively ablate and also to electrically activate/inactivate specific populations at will. Using these cutting edge tools and technologies, we hope to throw light on the development of neural circuits and the neural basis of locomotion.