填空题 When Sharon wag 5 years old, she realised something was horribly wrong. She was playing Blind Man's Bluff in her front garden. When the blindfold (蒙眼布) was removed, she didn't know where she wag. She has a (26) called developmental topographical disorientation (DTD). People with the condition struggle to form mental maps and so can't easily (27) . This means they get lost—a lot.
This kind of flipping, where Sharon's world suddenly becomes (28) , now happens to her throughout the day. As a child, Sharon told her mother what was happening. (29) , her mother said that she should never tell anyone, because they would think she was a (30) and burn her. Sharon quickly found a way to reorientate herself. Whenever her world flipped, she took herself somewhere private, closed her eyes and (31) in circles. "I open my eyes and the world is back to normal." Then, almost 20 years later, a friend persuaded her to write to the (32) neurologist Oliver Sacks. She didn't think he would write back, but he did reply, suggesting that she might have topographagnosia—an orientation (33) that results from brain injury. Since then, Sharon has taken part in several studies. These all show that people with DTD have no problems with their memory or (34) . They can follow spoken directions and their brains are anatomically normal. However, there does seem to be decreased communication between two brain areas: the right hippocampus, (35) memory, and the prefrontal cortex, which is important for monitoring information, attention and working memory.