Dr. Gautam Awatramani

Research in our lab aims to understand how specific elements of neural circuits in the brain interact through synapses to process relevant information. This is a considerable challenge since neurons are typically not isolated but entangled in an intricate mesh of overlapping circuits.

To this end, we use mouse genetics to ‘light up’ specific circuits in the brain with green fluorescent protein (GFP). One of the most accessible and anatomically well-defined parts of the brain is the retina. We use the retina as a model system to study the properties of synaptic interactions within specific genetically identified circuits.

Amazingly, when carefully removed from the eye and placed in oxygenated salt and glucose-containing solutions, the retina continues to ‘see’.  We can thus present pictures of all sorts to a little piece of retina placed under the microscope and directly observe how different circuit components extract relevant visual information, using a variety of techniques.

Biology 404

Sethuramanujam S, Yao X, deRosenroll G, Briggman KL, Field GD and Awatramani GB (2017) "Silent" NMDA Synapses Enhance Motion Sensitivity in a Mature Retinal Circuit.
Neuron. 2017 Dec 6;96(5):1099-1111.e3. doi: 10.1016/j.neuron.2017.09.058. Epub 2017 Nov 5.

Sethuramanujam S, Hoggarth A, Schwab DJ and Awatramani GB (2016) A central role for mixed acetylcholine/GABA transmission in direction coding in the retina
Neuron Jun 15;90(6):1243-56.

Hoggarth A, McLaughlin AJ, Ronellenfitch K, Trenholm S, Vasandani R, Sethuramanujam S, Schwab D, Briggman KL, Awatramani GB. (2015) Specific wiring of distinct amacrine cells in the directionally selective retinal circuit permits independent coding of direction and size.
Neuron. Apr 8;86(1):276-91.

Trenholm S, McLaughlin AJ, Schwab DJ, Turner MH, Smith RG, Rieke F, Awatramani GB. (2014) Nonlinear dendritic integration of electrical and chemical synaptic inputs drives fine-scale correlations.
Nat Neurosci. Dec;17(12):1759-66. 

Szikra T, Trenholm S, Drinnenberg A, Jüttner J, Raics Z, Farrow K, Biel M, Awatramani G, Clark DA, Sahel JA, da Silveira RA, Roska B. (2014) Rods in daylight act as relay cells for cone-driven horizontal cell-mediated surround inhibition.
Nat Neurosci. 2014 Dec;17(12):1728-35. 

Trenholm S, McLaughlin AJ, Schwab DJ, Awatramani GB (2013). Dynamic tuning of electrical and chemical synaptic transmission in a network of motion coding retinal neurons.
J Neurosci. Sep 11;33(37):14927-38. 

Trenholm S, Schwab DJ, Balasubramanian V, Awatramani GB (2013) Lag normalization in an electrically coupled neural network.
Nat Neuroscience. 2013 Jan 13.

Trenholm S, Borowska JB, Zhang J, Hoggarth A, Johnson K, Barnes S, Lewis TJ and Awatramani GB (2012)  Intrinsic oscillatory activity arising within the electrically-coupled AII amacrine/ON cone bipolar cell network is driven by voltage-gated Na⁺ channels
JPhysiol  May 1; 2501-17. 

Trenholm S, Johnson K, Smith R and Awatramani GB (2011) Parallel mechanisms encode direction in the retina
Neuron Aug 25;71(4):683-94. 

Borowska JB, Trenholm S and Awatramani GB (2011)  An intrinsic neural oscillator in the degenerating mouse retina
JNeurosci  31(13):5000-12.