After complaining of nausea and dizziness, a young Chinese woman underwent medical examinations only to discover a strange cavity inside the skull where her cerebellum should have been. Until now, only 8 other such cases had been reported worldwide. This surprising story is an excellent illustration of the brain’s capacity for adaptation.

The cerebellum is the portion of the brain located at the back of the skull, just below the brain. Because of its shape and structure, it is often called the little brain. But don’t let its small size fool you! It contains a significant number of neurons and plays an essential role in motor control. The cerebellum is critical in movement synchronization, fine motor coordination, balance, posture, and speech articulation.

The woman discovered this rare anomaly at the age of 24. Having found no trace of cerebellar tissue, doctors concluded that she had carried the abnormality since birth and that her cerebellum had never developed. The region in question was instead filled with cerebrospinal fluid. The situation forced her nervous system to adapt, demonstrating the brain’s remarkable plasticity. Scientists believe that the cerebral cortex replaced the functions of the cerebellum, allowing the woman to walk and speak, albeit imperfectly. As a child, her mother had remarked that she did not stand up until 4 years of age and did not start walking until 7. Her speech was also delayed to the age of 6. To this day, the woman has difficulties walking and suffers from slurred speech.

While scientists have a number of hypotheses, additional tests will be necessary to understand exactly how this patient manages to walk and speak in the absence of a cerebellum.