Frostig 9507936 It has become clear just recently that the adult brain can reorganize its connections. One of the situations during which connections seem to change is when new behaviors are learned. With this award, Dr. Frostig will study how the brain's representation of different sound frequencies is altered as an animal is trained to discriminate certain frequencies. This will be done using new techniques to repeatedly image the activity levels of brain tissue in a non-invasive way. This work will provide new information on the time course of plastic changes in the brain, and will allow Dr. Frostig's group to study the relationship of specific behavioral capacities to specific changes in brain organization. ***