# A modular, adaptable, and accessible implant kit for chronic electrophysiological recordings in rats

## TL;DR

This paper introduces a modular, low-cost implant kit for chronic electrophysiological recordings in rats, enabling precise and adaptable brain monitoring.

## Contribution

The novel contribution is a comprehensive, open-source, and adaptable implant kit with micron-level vertical adjustment for chronic recordings.

## Key findings

- The implant kit allows for precise vertical adjustment of probes to locate strong neuronal activity.
- The modular design supports adaptability to different recording systems and probe types.
- The protocol covers the full process from probe assembly to implantation, enhancing accessibility and reproducibility.

## Abstract

Electrophysiological implants enable exploration of the relationship between neuronal activity and behavior. These technologies evolve rapidly, with multiple iterations of recording systems developed and utilized. Chronic implants must address a litany of complications, including retention of high signal-to-noise ratio in probes and the ability to withstand excess force over the experimental period. To overcome these issues, we designed a chronic implant for rats. Our comprehensive protocol optimizes the entire implant process, from assembling and testing the probes (Neuropixels) to implantation. In addition to addressing the complications previously mentioned, our implant can vertically adjust probes with micron precision and is constructed using modular components, allowing it to be easily modified for various research contexts, electrophysiological recording systems, headstages, and probe types.

•We develop a modular implant for electrophysiological recordings in rats•The implant kit allows testing and calibration and facilitates implantation•The kit enables vertical adjustment of probes with micron precision•The implant is adaptable: e.g., optical fibers or different probe types may be added

We develop a modular implant for electrophysiological recordings in rats

The implant kit allows testing and calibration and facilitates implantation

The kit enables vertical adjustment of probes with micron precision

The implant is adaptable: e.g., optical fibers or different probe types may be added

The evolution of electrophysiological technologies and methods for recording extracellular electrophysiological data creates a need for adaptable and modifiable devices that can remain useful over time. Chronic implants that enable vertical movement of implantable probes enable researchers to search for strong neuronal activity within brain tissue over time. However, this must be done slowly to reduce irritation of the tissue. Our objective was to provide a comprehensive, open-source, and low-cost implantation kit to facilitate this process.

Ibáñez Alcalá et al. developed a highly adaptable implant, usable for chronic recordings in rats with high precision of brain targeting. Fundamental ideas that are implemented include modularity, precise vertical adjustment, adaptability to different recording systems, accessibility prioritization, and a comprehensive pipeline from building to implantation that could guide future implant development.