This priming occurs as a result of the finely tuned wiring of neural networks within the brain's visual system, say researchers at the Howard Hughes Medical Institute at the University of California, Berkeley. Even before birth, the brain is abuzz with activity as it begins to wire itself. Shatz's lab was among the first to demonstrate that early spontaneous neural activity promotes the organization of billions of nerve cells within animal and human brains. Their latest research shows that if that spontaneous neural activity is blocked, correct neural circuits in the visual system are not established and vision cannot occur. This is a lifelong process.
Experience helps change connections in the brain.
The research has implications for understanding fetal development, says coauthor Anna Penn, a neurobiologist at the University of California, Berkeley. Some illicit drugs, and even nicotine, can interfere with necessary synaptic transmission. Since much of the developing brain grows in a predetermined way, major nerve connections between parts of the brain are established early. Once the trunk line is established, detailed connections between the brain and the eyes must be made specific buildings in Manhattan and the Bronx must be wired for telephone service. This is like autodialing, Shatz says.