Cognition: Wireless EEG recording in mice

Research details

Challenge Contractor: Professor Esther Rodriguez-Villegas

Organisation: Imperial College London

Start date: 2012

Duration: 3 years

Amount: £0.5M

Sponsor: Eli Lilly

Case study

The Challenge

EEG recordings are conducted in mice to understand neural activity and how it relates to specific behaviours or cognitive tasks (e.g. memory, learning and decision-making) that are relevant to understanding brain disorders such as schizophrenia and Alzheimer’s disease. Studies typically involve the use of tethered recording systems which restrict the mouse’s movement and the testing paradigms they can be used in. Alternative wireless recording devices are available, but even the state-of-the-art are heavy for the mice to carry for prolonged periods (equivalent to a human carrying a 6kg weight on their head) and maintaining an upright head posture can be difficult for the animals. The devices also have a limited battery life of around four hours.

To address the animal welfare and technical challenges associated with existing recording systems, Lilly posed the Cognition Challenge to develop an ultra lightweight EEG recording device for use in awake, freely moving mice in a range of behavioural tests.

The product

The Cognition Challenge was awarded to Professor Esther Rodriguez-Villegas, an expert in low power electronics at Imperial College London. By re-designing the wireless circuitry and focusing on energy efficiency, Esther and her team of engineers worked with Lilly scientists to develop and test a device called TaiNi.

TaiNi weighs just 1.5g (including the battery). It is capable of 72 hours recording from 16 channels and of capturing local field and action potentials from mice performing a range of tasks, with data synchronisation to behaviour with sub-second precision.

3Rs and scientific benefits

Mice wearing the TaiNi device can move freely, exhibit natural behaviours and, unlike with other wireless and tethered systems, can be socially housed. This has animal welfare benefits as well as providing the potential to conduct for the first-time electrophysiology on socially interacting animals. The TaiNi device is lighter than other commercially available wireless devices or tethered recording systems. In studies of spatial working memory using an automated T-maze task, the Lilly scientists compared the number of trials mice completed when wearing a commercially available 4g wireless device, the TaiNi device, or no transmitter. Mice wearing the TaiNi device perform only 6.5% (mean of 47 trials per mouse) fewer trials compared with animals without a transmitter, whereas those with the heavier device perform 35.9% (mean of 31 trials per mouse) fewer trials, illustrating the impact device weight has on the mice. The ability to complete additional trials increases the statistical power and provides the opportunity to reduce the number of animals required for a given experiment.

The improved battery life offered by the TaiNi device – approximately 17 times longer than competitor products – means that mice do not have to be handled as frequently to change the battery (or to untwist the tethered systems). Handling is known to affect mouse welfare and the reliability of behavioural data and the Lilly scientists have shown that using the TaiNi device they can record for long periods of time without disturbing the mice, including over multiple diurnal cycles. These technical improvements have already allowed the identification of the novel phenomena of discrete categories of 140–220Hz ripple-oscillations that are thought to play a critical role in long-term memory.

Wider impacts

Esther and her team have established a new spin-out company called TainiTec to commercialise the TaiNi device. Since its formation in 2017, they have built a customer base which includes academic research laboratories and pharmaceutical companies. With a £50k award from the NC3Rs Business Growth Scheme the team are working on optimising the production process to ensure that they can meet current demand for the device from European-based organisations and ultimately expand into the US market.

Lilly are working with Esther to apply TaiNi across their drug discovery pipeline. They have so far deployed 16 devices to support a variety of research projects and are investing in new infrastructure, including computer hardware and the re-design of experimental suites, to accommodate their switch from less refined recording devices. TaiNi has been promoted by Lilly to other pharmaceutical companies and collaborators, including through the EU Innovative Medicines Initiative project, PRISM. In 2018, the NC3Rs awarded £75k to a team at the University of Exeter to test the use of the TaiNi device for a contextual memory task, in a collaboration with Lilly scientists to ensure the transfer of skills and experience.

The development and validation of TaiNi was published in Scientific Reports in 2017. In 2018, Esther was awarded the Imperial College London Provost’s Award for Excellence in Animal Research and the AAALAC/IQ Consortium Global 3Rs Award for Europe.

Sponsor in-kind contributions

Lilly provided a range of in-kind contributions. This included in-house testing of prototype devices in real-world experimental settings, scientific validation studies to build confidence in the device, changes in infrastructure to accommodate the experimental set-up for the device, and the provision of computing hardware for data capture and analytics from the TaiNi device. Lilly also provided 0.75 of a full-time equivalent (scientific and engineering staff) per year and a total financial contribution of £0.15M to support the prototype evaluation.

This case study was published in our 2019 CRACK IT Review.