Comment »Posted on Thursday 14 August 2008 at 4:48 pm by Jacob Aron
In Biology, Inventions & Technology

What constitutes a brain? Scientists at the University of Reading have connected neurons from the foetus of a rat to a bank of electrodes which control a small robot. You can watch the robot learning to turn in this video:

This experiment has been widely reported by the media as a “rat-brained robot”. This instantly conjures up the mental image of a B-movie experiment gone horrible wrong – “Rat-Brained Robots…FROM SPACE!” perhaps – quite far from reality.

Neurons are the cells that make up the majority of the nervous system, including the brain. There are around 100 billion of these cells in a human brain. The robot is controlled by 300,000 rat neurons, less than 2% of the 21 million in a rat brain. Do these randomly connecting neurons make a brain? Clearly one neuron cannot be call a brain – it’s just a single cell after all. At what point do you go from a clump of neurons to a fully fledged brain? The Reading team themselves are unclear on this point, using phrases such as “brain material” and “brain culture” along with just plain old “brain”.

What is clear is this experiment is not “cruel”, as many commenters on the news websites seem to be saying. They haven’t cut the brain from a living adult rat and placed it into a robot in some kind of twisted transplantation – for one thing, I imagine they would have no idea how to hook up a rat brain to a robot. The neurons aren’t even physically attached to the robot, as their organic nature requires a temperature-controlled environment. Instead, communication takes place with the robot via Bluetooth.

So what’s the point of it all? Once the robot has learnt to navigate its environment and recognise its surroundings by forming connections between neurons, the researchers plan to disrupt these connections in an attempt to recreate conditions that cause memory loss such as Alzheimer’s and Parkinson’s disease. In other words, they aren’t trying to build an army of robo-rat slaves.


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