# Ultra High-density Optomechanic Neural Interfaces

> **NIH NIH R21** · CARNEGIE-MELLON UNIVERSITY · 2021 · $210,616

## Abstract

Project Summary
A multi-scale, mechanistic understanding of neural circuits that includes both local- and whole-brain
interconnections still remains elusive. One of the fundamental challenges is the lack of tools for monitoring, with
high spatiotemporal resolution, the activity of local neuron ensembles simultaneously in different regions of the
brain in awake, freely-behaving animals. This calls for the design of ultrahigh density neural probes capable of
recording from thousands of neurons with high spatiotemporal resolution. While there has been tremendous
progress on the design of conventional passive and active electronic neural probes, these technologies are
reaching scaling limits. We need to break away from the conventional scheme of recording and relaying electrical
neural signals using passive or active electronic neural probes to enable breakthrough improvements in the
number of simultaneous channels that we can record from the brain. Here, we propose a disruptive approach
based on fundamental advancements in optics and microelectromechanical systems (MEMS) to deliver an
innovative opto-mechanical probe that can potentially have more than a couple of thousand simultaneously
active recording electrodes in the same footprint of a conventional passive probe. All of the recorded neural
signals in our design are encoded in the optics domain to leverage the ultrahigh bandwidth of light for
communicating the recorded aggregate neural signals to outside the brain on a single optical waveguide. In this
scheme, each recording channel is encoded onto a single wavelength of light that travels along the same
waveguide. This wavelength domain multiplexing (WDM) method enables a true simultaneous recording of many
channels, unlike the time domain multiplexing (TDM) scheme that is used in active electronic neural probes,
which relies on sequential recording of multiple channels. Therefore, our design enables massive scaling of the
number of simultaneously recorded channels, while enhancing SNR, preserving the bandwidth, and minimizing
adverse effects of active electronic neural probes such as heat generation inside the brain. The core unit cell of
our neural probe is an electromechanical sensor that detects electrical neural signals and converts them to small
mechanical motions of a membrane, which in turn modulates a photonic microresonator. Therefore, the electrical
neural signal is transformed to a mechanical and then an optical signal. The ultra-high quality factor optical
microresonator enhances the detected signals. A single common waveguide coupled to multiple microresonators
carries the optical signals to the backend outside the brain. This novel design enables massive scaling of the
number of recording channels without increasing the size of the neural probe. Moreover, the conversion of
electrical signals to optical signals results in enhanced signal-to-noise ratio (SNR) and also makes the
transmitted signals immune to unwanted electrical int...

## Key facts

- **NIH application ID:** 10294080
- **Project number:** 1R21EY033084-01
- **Recipient organization:** CARNEGIE-MELLON UNIVERSITY
- **Principal Investigator:** Maysamreza Chamanzar
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $210,616
- **Award type:** 1
- **Project period:** 2021-09-01 → 2023-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10294080

## Citation

> US National Institutes of Health, RePORTER application 10294080, Ultra High-density Optomechanic Neural Interfaces (1R21EY033084-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10294080. Licensed CC0.

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