Scientists have now taken a major step towards creating artificial intelligence, not in a robot or a silicon chip, but in a test tube.
Researchers at the California Institute of Technology (Caltech) have created a circuit of interacting molecules that can recall memories based on incomplete DNA patterns, just like the human brain.
“The brain is incredible. It allows us to recognise patterns of events, form memories, make decisions, and take actions,” says Lulu Qian, senior post—doctoral scholar in bioengineering at Caltech, the journal Nature reports.
“So we asked, instead of having a physically connected network of neural cells, can a soup of interacting molecules exhibit brainlike behaviour?” said Qian, who led the study.
Consisting of four artificial neurons made from 112 distinct DNA strands, the researchers’ neural network plays a mind—reading game in which it tries to identify a mystery scientist, according to a Caltech statement.
The researchers ‘trained’ the neural network to ‘know’ four scientists, whose identities are each represented by a specific, unique set of answers to four yes—or—no questions, such as whether the scientist was British.
After thinking of a scientist, a human player provides an incomplete subset of answers partially identifying the scientist.
The player then conveys those clues to the network by dropping DNA strands that correspond to those answers into the test tube.
Communicating via fluorescent signals, the network then identifies which scientist the player has in mind. Otherwise, the network can ‘say’ that it has insufficient information to pick just one of the scientists in its memory or that the clues contradict what it has remembered.
The researchers played this game with the network using 27 different ways of answering the questions — out of 81 total combinations — and it responded correctly each time.
This DNA—based neural network demonstrates the ability to take an incomplete pattern and figure out what it might represent — one of the brain’s unique features.
Biochemical systems with artificial intelligence — or at least some basic, decision—making capabilities — could have powerful applications in medicine, chemistry, and biological research, the researchers say.
In the future, such systems could operate within cells, helping to answer fundamental biological questions or diagnose a disease.
The human brain consists of 100 billion neurons, but creating a network with just 40 of these DNA—based neurons — 10 times larger than the demonstrated network — would be a challenge, according to the researchers.
