Cornell researchers have developed a lightweight wireless device that can record brain activity from animals moving freely in natural environments, giving scientists a new way to study behavior that has been difficult or impossible to reproduce in laboratories.
The device, called the Wireless, Interactive, Lightweight Datalogger, or WILD, weighs less than a U.S. dime and can monitor groups of neurons for extended periods while also tracking movement, orientation, vocalizations and eye activity.
A proof-of-concept study published Sept. 10 in Nature Methods describes how the technology was used to record brain activity in groups of mice living and interacting in an outdoor field setting for more than two weeks.
Researchers said the system bridges a longstanding gap in neuroscience: laboratory tools can provide detailed neural recordings, while field studies capture natural behavior, but until now researchers have had difficulty doing both at the same time.
“Before you could either record neural activity with high resolution in the lab or you could record behavior in nature – now we can do both,” said Azahara Oliva, an assistant professor of neurobiology and behavior in Cornell’s College of Arts and Sciences.
Studying social behavior outside the lab
The research team said WILD could make it possible to study how animals coordinate complex social behaviors, including raising young, defending territory, building nests and forming colonies.
Antonio Fernandez-Ruiz, an associate professor of neurobiology and behavior and a co-senior author of the study, said those kinds of questions require animals to interact freely rather than being constrained by traditional laboratory equipment.
Previous approaches often relied on tethers or heavier wireless devices that could interfere with normal movement and were difficult to use outdoors because of humidity and moisture.
WILD was designed to withstand field conditions while remaining small enough not to significantly restrict movement.
The system is modular, allowing researchers to add or remove components depending on the experiment.
Device can record and manipulate brain activity
The device does more than passively collect information.
Researchers can use light or electrical stimulation to manipulate specific brain mechanisms and then observe how behavior changes.
WILD can also be programmed to respond automatically when it detects a particular brain pattern or behavior.
Depending on battery size, the device can record continuously for roughly three to nine hours. Researchers can extend that period by programming it to conserve power when an animal is inactive.
The technology is already being used by collaborators studying other animals, including birds, bats and monkeys.
First field recordings of place cells
In experiments conducted north of Cornell’s campus, researchers used WILD to record what are known as “place cells” as mice moved through a large outdoor enclosure.
Place cells are neurons associated with an animal’s internal representation of location.
Fernandez-Ruiz said the researchers found some similarities between field recordings and what has been observed in controlled laboratory experiments, but also significant differences that are now being investigated.
“This paper is the proof-of-concept that we were able to identify these place cells outside the laboratory,” Fernandez-Ruiz said.
The findings could help researchers better understand how brains process space, social interaction and environmental change under real-world conditions.
Technology made open source
The Cornell team has made the materials needed to build the device open source.
Researchers said that approach is intended to allow other laboratories to customize the system and build additional modules rather than starting from scratch.
Oliva said making the technology broadly available could accelerate progress across the field.
Cornell researchers plan to use WILD to study group problem-solving, seasonal effects on the brain, social dynamics related to neurodivergence and the long-term neurological effects of psychedelics.
Future modules could also measure physiological information such as heart rate, body temperature and glucose levels.
The researchers said the project benefited from Cornell resources including the Cornell NanoScale Facility and the university’s AI for Science Institute, along with expertise spanning neuroscience, engineering and computer science.
The team moved from an early prototype to outdoor testing in about two years.
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