Using human researchers to observe test subject behaviour during research experiments can be time consuming and expensive. The available manpower for real-time observation is limited, and human observations are inherently subjective. To address some of these limitations, the Tufts Centre for Regenerative and Developmental Biology has partnered with Wireless Techniques to develop the first automated learning and testing chamber for analysing behaviour in small animals. The chamber uses a Cognex In-Sight Micro vision system instead of a human researcher to observe the behaviour of test subjects.
Tufts researchers are using the new testing chamber to study the molecular mechanisms underlying the abilities of living things to learn from their environment. Light stimuli are used to train worms and tadpoles on specific tasks, and the animals are then tested for recall in a variety of molecular-genetic and pharmacological experiments. The new tracking system provides quantitative data on the subjects’ behaviour and performance in learning assays; this is a unique system, the first that allows not simply tracking of animal movement but actually gives parallel, independent feedback to each subject so they can learn specific tasks. Simple animals such as flatworms share many of the same behavioural pathways and neurotransmitters with human beings, so these animals are frequently studied to better understand the properties of memory storage and transmission in tissue. The new chamber makes it possible to test new drug compounds to see if they have any impact on cognitive ability.
“Modern cognitive science is striving to understand the connection between molecular genetics and the information processing mechanisms that give rise to behaviour and thought,” says Professor Michael Levin, director of The Tufts Centre for Regenerative and Developmental Biology. “The biomedical aspect of this goal includes the search for drugs that will aid learning and memory and the understanding of various influences on cognition.”
In a typical experiment, worms will be trained to stay in, or avoid, specific parts of the dish or to move at specific rates. Worms that successfully perform the task will be rewarded by lowered light levels (worms inherently prefer the dark).
Up to now, studies have been performed manually. But the manual approach of assessing behaviour puts significant limits on experimental progress. Only a limited number of animals can be analysed by hand due to manpower and cost limitations. Manual handling also introduces the potential for the results to be affected by the judgment and errors of the person running the experiment.
The Tufts Centre selected Wireless Techniques to design and build an automated learning and testing chamber that could provide real-time feedback without a human researcher. Cognex was chosen as the vision system supplier because its sophisticated image processing tools provided the ability to determine the position of the worms despite complicated shadowing effects created by the movement of the water in the test chamber.
How the chamber works
The chamber consists of 12 cells arranged in a grid, each holding a disposable Petri dish where the worm lives. The environment in each cell is individually controlled by the software depending on the behaviour of the animal within. The lid contains a series of light emitting diodes (LEDs) controlled by a computer that are used to train worms.
Because the system is automated, 12 experiments can be run simultaneously seven days a week, 24 hours a day without human intervention. As a result, much larger sample sizes can be achieved, and experiments can also be run for much longer periods. Millions of observation and training cycles can be performed, a level of training far beyond what can realistically be accomplished by manual methods. The system also provides complete consistency among experiments, allowing labs to replicate experiments performed elsewhere.