Professor Ranganath's research concerns the neurocognitive structure of human memory and executive control. One set of studies currently underway concerns the relationship between short-term, or working memory, and long-term memory. Results from event-related fMRI studies conducted by Professor Ranganath suggest that overlapping regions of the prefrontal cortex and medial temporal lobes are active during both working memory and long-term memory tasks.
This research suggests that a common neural system supports both of these types of memory. Currently, Professor Ranganath is investigating how different regions within the prefrontal cortex and medial temporal lobes contribute to working and long-term memory through additional fMRI studies of healthy young adults and behavioral testing of patients with focal brain damage. A second, related area of interest is the role of prefrontal cortex in the control and evaluation of information in memory.
Finally, in collaboration with Andy Yonelinas, Professor Ranganath is investigating the roles of different medial temporal lobe regions in recognition memory processes. To address this issue, he is conducting parallel studies using event-related fMRI and event-related brain potentials in healthy young and older adults and amnesic patients with medial temporal lobe damage. In collaboration with another research group, he is also conducting studies to examine field potentials recorded directly from the human hippocampal formation in patients performing recognition memory tasks.