Rats vs. computers vs. rat cyborgs in maze navigation

Is there a human metaphor here somewhere?
March 7, 2016

Experimental system for maze solving (credit: Yipeng Yu/PLoS ONE)

What would happen if we combined synthetic and biological systems, creating an intelligent cyborg rat? How would it perform?

Researchers in China decided to find out by comparing the problem-solving abilities of rats, computers, and rat-computer “cyborgs,” as they reported in an open-access PLOS ONE paper.

Rats: Six rats were trained for a week to run a series of unique mazes. After training, the researchers tested the rats on 14 new mazes, monitoring their paths, strategies and time spent solving the mazes.

Maze-solving computer algorithm: Implementing left-hand and right-hand wall-following rules, the algorithm completed the same 14 mazes run by the rats.

Electrode implant in a laboratory rat used to deliver electrical stimulation to the brain (credit: Vdegroot at Dutch Wikipedia/Creative Commons)

Rat cyborgs: The rats were implanted with a wireless microstimulator mounted on the back of the rat to deliver electric stimuli via microelectrodes into their somatosensory cortex and medial forebrain bundle, which releases dopamine to the nucleus accumbens and is a key node of the brain’s reward system. The computer tracked the rats, analyzed the explored maze information, and decided when and how to intervene when the rats needed help in traversing unique paths and avoiding dead ends and loops (by stimulating the rats’ left and right somatosensory cortex to prompt them to move left or right).

Rat cyborg in maze (credit: Yipeng Yu/PLoS ONE)

Intelligent cyborgs beat both rats and computer

Performance of the rats, computer and rat-cyborgs were compared by evaluating how many times they visited the same location (steps), how many locations they visited, and total time spent to reach the target. Although the cyborgs and computers took roughly the same number of steps, the cyborgs took fewer than the rats, a sign of more efficient problem solving. The cyborgs also visited fewer locations than computers or rats, and took less time than the rats to solve the mazes.*

The researchers suggest that the experiment shows that optimal intelligence may reside in the integration of animals and computers.

In future work, the researchers plan to introduce more tasks and the complexity of tasks will be quantified. “To avoid excessive intervention with the rats, the strength of the computer’s assistance will be graded,” the authors say in the paper. “In addition, more practical rat cyborgs will be investigated: the web camera will be replaced by sensors mounted on rats, such as tiny camera, ultrasonic sensors, infrared sensors, electric compass, and so on, to perceive the real unknown environment in real time; and the computer-aided algorithms can be housed on a wireless backpack stimulator instead of in the computer.”

* The computer aided the rats under three rules: (1) if there was a path to the unique road, the computer would find the shortest path, then Left and Right commands would be sent to navigate the rat to the unique road; (2) if the rat was going to enter a dead cell, Left or Right commands would be sent to prevent such a move; (3) if the rat was in a loop, the computer would find the shortest path to the current destination, then Left and Right commands would be sent to navigate the rat to follow the path.

Abstract of Intelligence-Augmented Rat Cyborgs in Maze Solving

Cyborg intelligence is an emerging kind of intelligence paradigm. It aims to deeply integrate machine intelligence with biological intelligence by connecting machines and living beings via neural interfaces, enhancing strength by combining the biological cognition capability with the machine computational capability. Cyborg intelligence is considered to be a new way to augment living beings with machine intelligence. In this paper, we build rat cyborgs to demonstrate how they can expedite the maze escape task with integration of machine intelligence. We compare the performance of maze solving by computer, by individual rats, and by computer-aided rats (i.e. rat cyborgs). They were asked to find their way from a constant entrance to a constant exit in fourteen diverse mazes. Performance of maze solving was measured by steps, coverage rates, and time spent. The experimental results with six rats and their intelligence-augmented rat cyborgs show that rat cyborgs have the best performance in escaping from mazes. These results provide a proof-of-principle demonstration for cyborg intelligence. In addition, our novel cyborg intelligent system (rat cyborg) has great potential in various applications, such as search and rescue in complex terrains.