# Transparent graphene electrode arrays for simultaneous electrical and optical investigation of computations in the olfactory bulb

> **NIH NIH F32** · UNIVERSITY OF OREGON · 2020 · $69,554

## Abstract

Project Summary and Abstract
 A major obstacle to understanding the link between behavior and neuronal activity is the difficulty of
electrophysiologically recording the activity of large neuronal populations without limiting visual access. Electrode
arrays directly measure electrical signals and offer significantly greater temporal resolution than optical
fluorescence techniques, but the resulting obstruction of optical access limits the ability to pair electrode arrays
with optogenetic stimulation and calcium imaging. In order to better pair these tools, a new approach to the
neuron-electrode interface is required. We propose to fabricate a high-density array of active graphene
devices on a transparent flexible substrate for in vivo applications. This novel design will address critical
barriers to progress in the field of in vivo neural recording technology: improved signal strength, high temporal
resolution, high sensor density, and improved biocompatibility with the unique aspect of transparency.
 In the first aim, we will develop a surface graphene electrode array (GEA). Critically, the ease of
fabrication will allow us to iterate through slight alterations to the GEA design, such as electrode geometry and
the flexibility of the support layer through fractal cuts to optimize its ability to mimic the environment. This
biomimetic design will result in higher sensitivity through more intimate contact with cells of interest while
minimizing damage for long term recordings. The local signal amplification resulting from the field effect response
of graphene will make result in a device with an unprecedented level of biocompatibility and sensitivity. This
transparent GEA will first be applied to record the activity of the sensory input to the olfactory bulb, located in
glomeruli at the surface of the brain. To validate this array, we will image this sensory input in concert with GEA
recording. This will allow us to determine whether the GEA can faithfully recover the spatial pattern of OB
glomerular responses. We will then implement this array to map the transfer function between the sensory neuron
inputs and the output neurons of the OB.
 In the second aim, we will insert the GEA deep into the brain and record from granule cells, a population
of small interneurons located deep in the brain, which form reciprocal synapses with the output neurons of OB.
While recording electrically from granule cells, we will image calcium signals in the output neurons. Comparison
of these recordings will elucidate the computations that these neurons perform. Together, these experiments will
reveal how information is transformed as it moves between different cell types within a neural circuit. In addition,
this work will establish GEAs as a powerful tool for investigating neural circuits.

## Key facts

- **NIH application ID:** 9831569
- **Project number:** 5F32MH118724-02
- **Recipient organization:** UNIVERSITY OF OREGON
- **Principal Investigator:** Morgan A Brown
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $69,554
- **Award type:** 5
- **Project period:** 2019-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9831569

## Citation

> US National Institutes of Health, RePORTER application 9831569, Transparent graphene electrode arrays for simultaneous electrical and optical investigation of computations in the olfactory bulb (5F32MH118724-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9831569. Licensed CC0.

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