“I’m a neuroengineer, and one of my goals is building brains.”
Prof Steven Potter was disarmingly understated as he introduced himself.
It’s not that tissue engineering is unusual. Nor even that doing it with neural cells should be an issue.
If heart cells or skin cells can be reprogrammed, why not neurons?
But “building brains” had been my flip way of labelling an intriguing, indeed unnerving, branch of science: the neurophysiology of disembodied brain-cell cultures.
… Steven Potter, professor in the department of biomedical engineering at the Georgia Institute of Technology in the US, is insistent that words like “brain” and “mind” belong to his endeavour.
“One of the ways in which I differ from a lot of neuroscientists is to believe that there’s a spectrum of minds. There isn’t some point where the mind suddenly is there,” he said.
“I think that there is a different amount of mind in different animals. And even in you, whether you’ve had your coffee or not, whether you’re asleep or awake.
“There are always different levels of how much mind you have. So you could carry it all the way down to the cultured network, there is still some sort of proto-mind in there.”
The key tool in the Potter lab is the “multi-electrode array”, an upgraded version of the traditional Petri dish used in microbiology labs around the world, improved by the addition of an array of electrical contacts the researchers can use to “listen” in to the electrical activity of the neural cells.
Another researcher likens the device to an EEG, the electroencephalogram that clinicians use to check a patient’s brain activity.
The neural cultures themselves comprise a few tens of thousands of cells – a tiny fraction of the hundred billion or so that make up a human brain – “a little smear of brain” in the words of graduate student Michelle Kuykendal in the Potter lab.
Ben Whalley, from Reading University, has used a blob of brain cells to control a robot
You can’t expect much from them, Steve Potter concedes. “But we’re sure that [one of these cultures] has a lot of complex behaviour – even with 10,000 neurons. There are some insects, simpler animals, that have approximately the number of cells we have in our culture dishes,” he said.
… Reward chemicals, like dopamine, could be added to reinforce the achievement when the robot succeeds in a task. Dr Potter suggested that a culture that controls a dopamine delivery system directly could in some ways mimic addiction – it might learn to give itself chemical highs on demand.
But perhaps the most astonishing closed loop would be self-awareness, he said.
“Self-awareness is not a magical spark that human neurons have in them; it arises thanks to specific circuits that are monitoring what is going on in the human brain. Our cultures do not have that perception at the moment, but we could put it in.
“Our computer programme could monitor activity patterns and send the information back as a particular stimulation through the electrodes. That could be like their self-consciousness circuits. It would be a very rudimentary self-consciousness, but that is all it would take.”
It may seem a remote possibility. But already these cultures force us to accept the truth that no matter how mysterious and instinctive thinking feels, it all comes down to electrical and chemical signals flashing across the three pounds of matter between our ears.
“Most people that you talk to who study anything to do with the brain are in it for the mystery,” said Georgia Tech graduate student Michelle Kuykendal. …
Roland Pease was researching “Build Me a Brain” for BBC Radio 4’s Frontiers programme, which first aired on Wednesday 12 June.
They could be doing anything in there…