According to years of neurobiological research, neurons do not activate randomly but operate according to established patterns. The brain has a baseline activity known as the "default mode," which exists even when a person is not engaged in a specific task. This structure defines the range of possible reactions to sensory stimuli. When new signals—such as smell, taste, or images—are received, the brain adapts its primary patterns to the new sensations. Organoids show similar activity without any experience, indicating the inherent nature of this "operating system."
Debates about whether humans have innate structures of thought or if they are formed through experience have been ongoing among philosophers for centuries. However, a new study led by Tal Sharaf, a specialist in biomolecular engineering, suggests that knowledge may be innate. The team monitored the development of brain organoids—three-dimensional models of tissues formed from stem cells in the lab, without any sensory input. The results, published in the journal Nature Neuroscience, open new horizons in understanding neural architecture.
The brain is ready for cognition even before the emergence of experience
The human brain demonstrates the ability to process visual and auditory stimuli: organoid cells began to spontaneously generate electrical signals. These patterns of activity turned out to be similar to the "default mode"—the basic structure of activity in the adult brain responsible for processing information from all sensory organs.
"These cells interact with each other and form self-organizing circuits even before we gain any experience from the external world," comments Tal Sharaf. He emphasizes that there is an operating system that begins to develop before birth, and organoids allow us to glimpse a predecessor version of the brain's "software."
These discoveries hint at a genetically encoded plan for neural structure. "Self-regulating systems can serve as the foundation for forming an understanding of the surrounding world," adds Tal Sharaf. Evolution seems to have developed a way for the central nervous system to create a map for navigating and interacting with the world even before the first encounter with it.
The results obtained open new avenues for researching developmental disorders of the nervous system and the impact of toxic substances, such as pesticides, on the developing brain.
