Home-enclosure based behavioral and wireless neural recording setup for unrestrained rhesus macaques

Abstract

Electrophysiological studies with behaving non-human primates (NHP) often require the separation of animals from their social group as well as partial movement restraint to perform well controlled experiments. When the research goal per se does not mandate constraining the animals’ movements there are often still experimental needs imposed by tethered data acquisition. Recent technological advances meanwhile allow wireless neurophysiological recordings at high band-width in limited-size enclosures. Here, we demonstrate wireless neural recordings at single unit resolution from unrestrained Rhesus macaques while they performed self-paced, structured visuomotor tasks on our custom-built, stand-alone touchscreen system (XBI) in their home environment. We were able to successfully characterize neural tuning to task parameters, such as visuo-spatial selectivity during movement planning and execution, as expected from existing findings obtained via setup-based neurophysiology recordings. We conclude that when movement restraint and/or a highly controlled, insulated environment are not necessary for scientific reasons, cage-based wireless neural recordings are a viable option. We propose an approach that allows the animals to engage in a self-paced manner with our XBI device, both for fully automatized training and cognitive testing, as well as neural data acquisition in their familiar environment, maintaining auditory and sometimes visual contact with their conspecifics.

Significance statement

Cage-based cognitive systems have previously been shown to be highly useful in cognitive assessment of non-human primates. These systems allow animals to engage with the task/system in an unrestrained and self-paced manner. We expanded the capabilities of our own cage-based testing device by combining cognitive testing with wireless neural recordings in the animals’ home environment, in an upscalable approach. When neither movement constraints nor specialized equipment are scientifically necessary, our approach allows for the combination of cognitive testing with intracranial electrophysiology without removing the animal from its home environment, potentially improving animal well-being.