The procedure has been to image the brain during different points of learning and to compare pathways active during initial and overlearned task performance. Our longer-term objective is to track these pathways continuously during the transition from naive to skilled performance. We all know that we can remember sounds and visual images from the past. However, it is largely a mystery how the human brain revives and represents these memories during retrieval. We are examining one possible solution to this issue by testing whether human visual processing areas become active when individuals remember visually based memories, and whether auditory processing areas become active when sounds from the past are remembered.
Initial studies indicate that sensory-specific regions are reactivated during memorization.
Brain activity was then imaged while subjects retrieved individual items that had been either studied as pictures or sounds, using cues that were neither pictures nor sounds. Results showed visual cortex activity increases during picture recall and auditory cortex activity increases during sound recall. Frontal regions were also concurrently activated with the sensory-specific regions of visual and auditory cortex. These results collectively suggest that, during recollection, frontal regions modulate posterior sensory-specific regions to reinstate a memory. Fifty percent of adults over the age of 85 experience some form of dementia such as Alzheimer's disease, which often begins with memory lapses and progresses to severe cognitive and behavioral dysfunction.