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The EUPRIM-Net Project

WP9: Monkey “home office” – Telemetry for cage-based wireless recordings in unrestrained monkeys

Recording of physiological data, especially invasively, but also non-invasively, often requires that animals are
handled and restrained in their movements during the experimental procedures. In system neuroscience, for
example, constraining the animal’s head movements is the standard procedure for microelectrode recordings
from the animal’s brain, while the animal performs cognitive tasks. The interaction with the animal bears the
potential to induce stress, which should be avoided, might be detrimental to the behavioural learning progresses,
and can have confounding effects on the physiological parameters in question. If physiological data is not
collected for research purposes, but to monitor animal welfare in a colony, such stress leads to the paradoxical
situation that attempts to optimize animal welfare might actually reduce it.

The objective of the WP is to develop and implement procedures for remotely monitoring physiological and
behavioural data from monkeys in their housing environments. Telemetry systems will be combined with
behavioural test systems for integrated and automated data collection. The expected impact is a considerable
reduction of potential stress for monkeys in experimental situations, and improved possibilities to continuously
monitor animal welfare.

The WP has two major goals. These will be achieved by synergistically merging three a-priori independent
technologies: a cage-based behavioural test system (Task 1), a remote physiological stress response monitoring
system (Task 2), and a telemetric neurophysiological recording system (Task 3). Before the systems can be
merged (Task 4) available systems have to be adapted (Task 1-2) or new systems developed (Task 3).

As one major goal we want to combine cage-based automated behavioural test systems with telemetric
neurophysiological recordings. Digital telemetry systems, which provide robust data transmission with
high-bandwidth in real-time over several meters, will allow recordings of brain activity in unrestrained animals.
The goal is that monkeys can stay in their familiar environment, or even among their peers, and at the same time
conduct well-controlled and automatically rewarded behavioural tasks for research in system neuroscience and
neuroprosthetics. Currently, such experiments are only possible under much more constrained lab conditions.

As another major goal we want to quantitatively compare the impact of different experimental procedures
on the acute stress response of the animals. For this we will implement techniques for remote monitoring of
physiological parameters. These parameters should be indicative for the short-term stress level and health
status of the animals. Heart-rate, blood pressure, and core body temperature will be measured with implantable
telemetric probes without inducing additional stress by the procedure itself. We will use these low-bandwidth
implantable telemetry systems, which can identify each of many animals in a group, to compare the influence of
different experimental conditions on the acute stress response of the animals. Especially, we want to compare
the cage-based experimental situation, as we will develop and use it within this project, with more conventional
lab-based experimental conditions, as they are widely used so far.

Expected impact

We expect that our developments help to identify sources of stress and to reduce stress in research monkeys.
Induced stress is a confounding factor for many research questions. Reduction of stress contributes to
the refinement of studies by improving the quality of the collected data. As a consequence the number of
animals needed for a study is reduced and animal welfare in experimental conditions is improved. The WP
will substantially contribute to the 3 R-concept (reduction, refinement and replacement). Additional to the
development and implementation of novel cage-based experimental techniques the WP also aims at quantifying
the stress level which is induced by different experimental procedures. The results of these studies will help to
put bioethical decisions about animal experimentation procedures on a more solid scientific ground and thus will
have an important impact far beyond the laboratory.

Connection to other EUPRIM WPs and benefits outside the consortium

Assessment of stress levels in monkeys under different conditions is a major goal also in WP3 of EUPRIM-Net
II. Here in WP9 we focus on developing the techniques and the impact of different behavioural and physiological
experimental procedures on the acute stress responses of the animals. WP3 asks how the stress-level of
monkeys is affected when positive reinforcement learning is applied for everyday animal handling procedures.
The two projects will mutually benefit from each other’s expertise and experience by exchanging protocols for
measurement and analysis of stress-related physiological or endocrinological parameters.

Automated systems for behavioural testing and remote physiological monitoring, as proposed here, will benefit
neurophysiological, ethological, biomedical, and toxicological research in primates. Such technologies and
experimental procedures are of great interest to practically all European primate centers and labs. Additional to
implementing the developed procedures at the partner institutes of WP9, we expect a major interest from groups
outside the consortium. We will make the procedures and protocols which will be developed in WP9 available for
interested groups.