A fascinating case challenges our understanding of the human brain—a 44-year-old French man living with a significant portion of his brain missing. Instead of brain tissue, his skull is primarily filled with cerebrospinal fluid due to a condition known as hydrocephalus, commonly referred to as “water on the brain.” This condition occurs when excess fluid builds up in the cavities of the brain, exerting pressure and leading to the expansion of these cavities.
Despite having only a fraction of his brain functioning, the man leads a normal life. He is a family man with a wife and children and works as a civil servant. Cognitive psychologist Axel Cleeremans from the Université Libre in Brussels, who has discussed this case, noted that while the man’s IQ was tested at 84—slightly below the average range—he remains socially competent and well-adjusted. He originally sought medical assistance for leg pain, only to discover that most of his brain was missing.
This unique situation raises important questions about brain function and plasticity. As Cleeremans explains, it suggests that the brain’s adaptability is far greater than previously thought. The man’s ability to function normally challenges traditional theories that designate specific areas of the brain, such as the thalamus, as crucial for self-awareness and consciousness.
Cleeremans argues for a theory he calls “Radical Plasticity,” proposing that the brain continually learns and adapts, allowing it to maintain a sense of self-awareness even when most of its physical structure is absent. He describes consciousness as the brain’s self-referential ability to understand its own functions.
This case not only sheds light on the brain’s remarkable capacity to adapt but also invites us to reconsider what we know about consciousness and the biological processes underlying awareness. You can find the original study published in The Lancet.
