The research, published in the journal Scientific Reports, describes a new ultra lightweight wireless sensor system for recording neural activity in the brains of mice.

The TaiNi sensor system also avoids many of the welfare concerns associated with existing approaches to recording brain activity in mouse models.

TaiNi has been developed by engineers at Imperial College London in collaboration with the pharmaceutical company Eli Lilly, in their UK research labs. The research was funded by the National Centre for Replacement Refinement Research’s (NC3R) open innovation programme called the CRACK IT Challenge.

An electroencephalogram (EEG) is a test that detects electrical activity in a brain using small, flat metal discs called electrodes. Brain cells communicate via electrical impulses and are active all the time. This activity shows up as wavy lines on an EEG recording.

EEG recordings are typically conducted in mice to understand neural activity and how it relates to specific behaviours or cognitive tasks such as memory, learning and decision–making.

These studies are relevant for understanding brain disorders like schizophrenia and Alzheimer’s disease, and typically involve the use of wireless recording devices on the mouse’s head.

However, conventional technologies are heavy for the mice to carry and have limited battery life. Alternative approaches involve tethered recording systems, which restrict the mouse’s movement and the testing paradigms they can be used in.

In 2011, NC3Rs and Lilly challenged the scientific community to develop a lightweight EEG recording device that could be used in awake, freely moving unrestrained mice, including in a range of behavioural tests. The aim of the project was to address the animal welfare and technical issues associated with existing recording systems.

The £500k contract to solve the Challenge was won by Professor Esther Rodriguez–Villegas, from the Department of Electrical and Electronic Engineering at Imperial. Her research focuses on low power healthcare applications such as wearable sensors.

Professor Rodriguez Villegas said: “Animal research is absolutely vital if we are to solve the world’s most pressing health challenges. At the same time constantly improving the welfare of the animals that make life–saving research possible is absolutely essential and it is something that the UK research community is working hard to do.

“This has been an incredibly exciting and challenging project pushing the boundaries of microelectronics design and applying it in a truly novel area for us. The project has been a great example of the importance of radical thinking to find solutions to research problems which will have a massive impact. It has demonstrated that the best solutions often come from unexpected sources and the CRACK IT scheme from the NC3Rs is a great example of how to make this happen.”

The TaiNi device pushes the boundaries of low power electronics in terms of its size, weight, battery life and signal bandwidth. It has the potential to be transformative both in pharmaceutical and academic research for the study of neural networks.

The wireless low power device, which weighs just 1.5g, has been trialled in studies at Lilly. It is capable of 72 hours recording from 16 channels and of capturing all types of neural activity from mice performing a range of tasks in a variety of environments, with data synchronisation to behaviour with sub–second precision.