Lab rats have a new companion, but it's not friendly. Researchers at Waseda University in Tokyo, Japan, have developed a robotic rat called WR-3 whose job is to induce stress and depression in lab animals, creating models of psychological conditions on which new drugs can be tested.


Animal are used throughout medicine as models to test treatments for human conditions, including mental disorders like depression. Rats and mice get their sense of smell severed to induce something like depression, or are forced to swim for long periods, for instance. Other methods rely on genetic modification and environmental stress, but none is entirely satisfactory in recreating a human-like version of depression for treatment. Hiroyuki Ishii and his team aim to do better with WR-3.

The researchers tested WR-3's ability to depress two groups of 12 rats, measured by the somewhat crude assumption that a depressed rat moves around less. Rats in group A were constantly harassed by their robot counterpart, while the other rats were attacked intermittently and automatically by WR-3, whenever they moved. Ishii's team found that the deepest depression was triggered by intermittent attacks on a mature rat that had been constantly harassed in its youth.


The team say they plan to test their new model of depression against more conventional systems, like forced swimming.

The robot has been developed just as new research by Junhee Seok of Stanford University in Palo Alto, California, and colleagues shows that the use of mouse models for human conditions has led researchers trying to find treatments for sepsis, burns and trauma astray at a cost of billions of tax dollars. [Advanced Robotics]

Image by Takanishi Lab/Waseda University

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