Update: March 2012

I'm now a Postdoctoral Researcher with Jaimie Henderson and Krishna Shenoy in the Stanford Neural Prosthetics Laboratory, part of the BrainGate Team. This page will no longer be maintained. Thanks.

This website does not reflect the views of Weill Cornell Medical College or Cornell University.
(C) 2010 Chethan Pandarinath.

Graduate Research

The role of gap junction coupling in adjusting the information-gathering properties of neural networks

The nervous system has an impressive ability to self-adjust – as it moves from one environment to another, it can adjust its information processing to accomodate the new conditions. These adjustments are critical to our functioning, but the neural mechanisms that underlie them are not well-understood. How is it that a network can change its processing on the fly?

We studied the neural mechanisms that underlie one of the most well-known behavioral adjustments, the shift in visual integration time that occurs as an animal moves from a day to a night environment. Interestingly, we found that this shift is accomplished by the coupling and uncoupling of gap junctions among horizontal cells in the retina. In the night condition, strong coupling between horizontal cells acted as a shunt, which essentially inactivates these cells. This work demonstrated a novel mechanism that allows a network to change the activity of one of its cell classes, and shift its behavior from one state to another. Related Papers

Breakdown of symmetry in the ON and OFF pathways in the retina

The visual system divides the world into two pathways, one that responds to increments of light (ON) and one that responds to decrements (OFF). Traditionally, these pathways have been thought as been “equal and opposite” channels of information - that they respond to similar features of the visual scene, just with opposite polarity. Evidence has gradually accumulated that the two pathways contain differences, both at the physiological and perceptual levels. However, the purpose of these differences – and their functional role in vision – has yet to be described.

We studied the adjustment of these two pathways to day and night conditions. Surprisingly, the ON and OFF pathways make asymmetric adjustments with the change from day to a night environment. We show that these asymmetries correspond to differences in the physical world, specifically, to asymmetries in the detection of increments and decrements that arise at low light levels. The findings demonstrate an example of the nervous system adapting its processing to a constraint imposed by the natural world. The results also have implications for models of downstream processing (e.g. models for higher visual areas, such as LGN or visual cortex). Related Papers

Undergraduate Research

As an undergraduate in the Surface Sciences Laboratory under Dr. Bob Nemanich, I used Conductive Atomic Force Microscopy (C-AFM) to understand the current-voltage characteristics of Schottky Contacts (potential barriers formed at the interface between metals and semiconductors). Related Papers

Publications

• Symmetry breakdown in the ON and OFF pathways of the retina at night: functional implications.
  C. Pandarinath, J.D. Victor, S. Nirenberg
  Journal of Neuroscience, July; 30(30);10006-14. [Link]

• A novel mechanism for switching a neural system from one state to another.
  C. Pandarinath, I. Bomash, W.W. Tschetter, J.D. Victor, G.T. Prusky, S. Nirenberg
  Front Comput Neurosci, Mar;4:2 (2010) [Link].

• Ganglion cell adaptability: Does the coupling of horizontal cells play a role?
  K. Dedek, C. Pandarinath, N.M. Alam, K. Wellershaus, T. Schubert, K. Willecke, G.T. Prusky, R. Weiler, S. Nirenberg
  PLoS ONE, 3(3): e1714 (2008) [Link]

• Structural, microstroctural, and electrical porperties of gold films and Schottky contacts on remote plasma cleaned, n-type ZNO{0001} surfaces.
  B.J. Coppa, C.C. Fulton, S.M. Kiesel, R.F. Davis, C. Pandarinath, J.E. Burnette, R.J. Nemanich, D.J. Smith
  Journal of Applied Physics, 97:103571 (2005)

• Preparation and characterization of atomically clean stoichiometric surfaces of AlN(0001).
  W.J. Mecouch, B.P. Wagner, Z.J. Reitmeier, R.F. Davis, C. Pandarinath, B.J. Rodriguez, R. J. Nemanich
  Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 23:1 (2004)

Presentations

• A novel role for gap junction coupling: a mechanism for allowing neural networks to change states.
  S. Nirenberg, C. Pandarinath, I. Bomash, J.D. Victor, G.T. Prusky, W.W. Tschetter. Association for Research in Vision and Ophthalmology (2010), Fort Lauderdale, FL (Poster) [Abstract].

• A novel role for gap junction coupling: a mechanism for allowing neural networks to change states. S. Nirenberg, C. Pandarinath, I. Bomash, J.D. Victor, G.T. Prusky, W.W. Tschetter. Society for Neuroscience (2009), Chicago, IL (Poster) [Abstract].

• How neural systems adjust to different environments: an intriguing role for gap junction coupling.
  S. Nirenberg, C. Pandarinath, I. Bomash, J.D. Victor, W.W. Tschetter
  Computational and Systems Neuroscience (2009), Salt Lake City, UT. (Selected talk) [Abstract].

• Ganglion cell adaptability: Does the coupling of horizontal cells play a role?
  C. Pandarinath, K. Dedek, N.M. Alam, K. Wellershaus, T. Schubert, K. Willecke, G.T. Prusky, R. Weiler, S. Nirenberg
  Society for Neuroscience (2007), San Diego, CA. (Poster) [Abstract].

Teaching Experience

Cornell University, 2003-2005: I thoroughly enjoyed being a lab instructor for several circuits, microelectronics, and embedded systems classes in the Department of Electrical and Computer Engineering at Cornell Unversity:

North Carolina State University, 2001-2002: I also taught a laboratory class in the Department of Computer Science at NC State:

CV

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