Photo Interrupter Sensors (Ports) for Rodents
Ports are commonly used in experiments on animal behaviour. Several different port systems and designs exist and ports can feature visual, auditory or olfactorial stimuli or provide rewards such as water or food for the correct behavior. It is important that the port design (shape, size, position of sensors etc) and the material (color, hardness, odor and/or surface smoothness) are adapted to the experimental goals and the used animals. Port entries and exits can, for example, be monitored via an infrared beam (photo interrupter sensors). Visual or auditory cues can be integrated in the port or adjacent to it.
A Photo Interrupter is a transmission-type photo sensor, which typically consists of a light emitting elements and light receiving elements aligned facing each other in a single package, that works by detecting light blockage when a target object comes between both elements, acting as an optical switch. In behaviour science, ports are commonly used in experiments. Several different port systems and designs exist and ports can feature visual, auditory or olfactorial stimuli or provide rewards such as water or food for the correct behavior. It is important that the port design (shape, size, position of sensors etc) and the material (color, hardness, odor and/or surface smoothness) are adapted to the experimental goals and the used animals. Port entries and exits can, for example, be monitored via an infrared beam. Visual or auditory cues can be integrated in the port or adjacent to it. Together with the Medical University of Vienna we have refined ports for experimentation on rat behaviour.
In addition we would be happy to build other stimulus and response devices or dispensers according to your specifications, e.g. stimulus lights, response levers and keys, nose poke, response wheels, liquid and pellet dispenser and receptacle. Modular operant chambers, mazes, and cubicles to attenuate sound or electrical noise isolation can be build. We can develop and build all hardware and software needed to enable scientists to do exactly the experiment they want and guarantee long-term customer support incl. the availability of replacement parts and modifications of the original set-up/devices.
Please contact us if you require specific information about our technical ability to provide tools for rodent behavior experiments and associated costs or if you are looking for other technical solutions for your facility. Some interesting tools such as open operant chambers are available as open hardware.
Application Potential of Photo Interrupter Ports
Photo Interrupter Ports, also known as photoelectric sensors or photogates, are devices that use infrared light to detect the presence or movement of objects. They typically consist of a light emitter (usually an infrared LED) and a light receiver (usually a photodiode) placed opposite each other with a gap between them. When an object such as the studied animal interrupts the infrared beam, the sensor detects the interruption and produces an output signal that can be used to study (rodent) behaviour in a variety of ways. Here are a few examples:
Movement and activity monitoring: Photointerrupters can be placed along paths or routes commonly used by rodents, such as corridors, runways or entrances/exits to burrows or nests, or laboratory settings. When a rodent passes through the sensor, it interrupts the infrared beam and the sensor registers the event as a change in the output signal. By analysing the timing and frequency of these interruptions, researchers can e.g. study the rodents' movement patterns, activity levels and circadian rhythms, including their locomotor activity, exploration and resting periods.
Feeding and drinking behaviour: Photointerrupters can be integrated into feeding or drinking stations to monitor rodent eating or drinking behaviour. For example, a photo interrupter can be placed near a feeder or water bottle and when a rodent approaches and interacts with the port, it interrupts the infrared beam, allowing to measure the timing, duration and frequency of feeding or drinking events. This can provide insight into feeding patterns, food or water consumption rates and feeding preferences.
Social behaviour: Photointerrupters can also be used to study the social behaviour, such as social interactions or group dynamics. For example, sensors can be placed at the entrances and exits of social areas, such as nesting sites or communal areas, to detect when rodents enter or leave these areas. This can help researchers understand social dynamics such as territorial behaviour, dominance hierarchies or mating behaviour.
Learning and memory: Photointerrupters can be used in conjunction with operant conditioning paradigms to study learning and memory in rodents. For example, sensors can be placed at 'decision points' in a maze or T-junction, and when a rodent crosses the decision point, it interrupts the infrared beam and triggers an event such as a reward or punishment. By analyzing the timing and accuracy of the interruptions, researchers can assess the rodent's ability to learn and remember spatial or associative tasks.
Overall, photointerrupters are tools that can be used to non-invasively study various aspects of (rodent) behaviour in controlled laboratory settings or natural environments, providing valuable insights into behaviour, physiology and cognition.
Selected readings on How Ports, Cues and DISPENSERS can be used in behavioral experiments
- Duan, C. A., J. C. Erlich, and C. D. Brody. 2015. Requirement of prefrontal and midbrain regions for rapid executive control of behavior in the rat. Neuron 86:1491-1503.
- Márquez, C., S. M. Rennie, D. F. Costa, and M. A. Moita. 2015. Prosocial choice in rats depends on food-seeking behavior displayed by recipients. Current Biology 25:1736-1745.
- Rivalan, M., H. et al.. 2017. An Automated, Experimenter-Free Method for the Standardised, Operant Cognitive Testing of Rats. PLoS ONE 12:e0169476.
- Steinberg, E. E., R. Keiflin, J. R. Boivin, I. B. Witten, K. Deisseroth, and P. H. Janak. 2013. A causal link between prediction errors, dopamine neurons and learning. Nature Neuroscience 16:966-973.