Almut Hupbach: Memory Reconsolidation

Almut Hupbach, assistant professor of psychology, studies memory reconsolidation, a process that can alter long-term memories

One of the challenges for cognitive neuroscience is to explain how memories change over time. Memories do not provide a perfect record of the past and can be altered long after acquisition. The dynamic nature of memory probably allows us to update existing knowledge as we gather new information. Understanding the circumstances of memory change has important implications for public and private areas of life.

Almut Hupbach, assistant professor of psychology, studies memory reconsolidation, a process that can alter long-term memories. Hupbach and her colleagues have shown that upon reactivation memories enter a fragile state that allows for the incorporation of new information into existing memory. She points out that memory can be activated with fairly subtle reminders, such as spatial surroundings.

“Any form of modification is theoretically possible. Memories can be impaired, enhanced or new information can be added to existing knowledge.  Critically, memory updating depends on the strength of the memory.  Very strong memories, such as traumatic experiences, are difficult to update.” she says.

Working with researchers at Princeton University, Hupbach used an MRI scanner to examine whether the extent of memory reactivation during new learning predicts the amount of memory updating. While participants were in the scanner, they learned a set of simple object images interspersed with random scene images. After 48 hours, participants returned to the scanner and were reminded of the first session. Immediately afterward, they were given a second set of object images to learn, but critically this time, no scenes were presented. This allowed the researchers to use the participants’ neural activity for scene processing in Session 2 as an indicator of Set 1 memory reactivation. In a final memory test that was administered another 48 hours later, it was found that the more participants thought back to Session 1 during Session 2 (i.e., the more scene activity was detected) the more Set 2 objects were incorporated into Set 1 memory, demonstrating that the extent of updating depends on the extent of reactivation.

Recently, she has begun to investigate how reactivated memories react to stress. Her results suggest that reactivation itself can enhance memories, but that this enhancement is taken away if reactivation is followed by stress.