Physiological History: Volunteer suffered a blood clot during infancy which resulted in a left-hemisphere stroke.

Expected Result: In normal adults the left hemisphere is used for language and other cognitive functions. Extensive damage to this part of the brain usually results in severe cognitive deficiencies.

Observed Result: Volunteer is now 17 years old, and displays only very subtle cognitive deficiency. MRIs indicate little to no activity in the left hemisphere, suggesting its usual functions have been taken on by neuron sets in the right. Volunteer's age at the time of the stroke may have helped the brain to adapt.