Explained | What are ‘bio-computers’ and what can they tell us about the human brain? Premium

Move over artificial intelligence — scientists at Johns Hopkins University have outlined a plan for ‘organoid intelligence’.

The story so far: Scientists at Johns Hopkins University (JHU) recently outlined a plan for a potentially revolutionary new area of research called “organoid intelligence”, which aims to create “biocomputers”: where brain cultures grown in the lab are coupled to real-world sensors and input/output devices. The scientists expect the technology to harness the processing power of the brain and understand the biological basis of human cognition, learning, and various neurological disorders.

What is the premise of this technology?

Understanding how the human brain works has been a difficult challenge. Traditionally, researchers have used rat brains to investigate various human neurological disorders. While rats provide a simpler and more accessible system to study the brain, there are several differences in structure and function and obvious differences in the cognitive capacities of rodents and humans.

In a quest to develop systems that are more relevant to humans, scientists are building 3D cultures of brain tissue in the lab, also called brain organoids. These “mini-brains” (with a size of up to 4 mm) are built using human stem cells and capture many structural and functional features of a developing human brain. Researchers are now using them to study human brain development and test drugs to see how they respond.

However, the human brain also requires various sensory inputs (touch, smell, vision, etc.) to develop into the complex organ it is, and brain organoids developed in the lab aren’t sophisticated enough. The organoids currently also don’t have blood circulation, which limits how they can grow.

Aren’t there other ways to study the human brain?

Recently, scientists transplanted these human brain organoid cultures into rat brains, where they formed connections with the rat brain, which in turn provided circulating blood. Since the organoids had been transplanted to the visual system, when the scientists showed the experimental rats a light flash, the human neurons were activated, too, indicating that the human brain organoids were also functionally active.