Poster F70, Tuesday, March 27, 8:00-10:00 am, Exhibit Hall C
Tracking the impact of retrieval suppression on individual memory representations
Ann-Kristin Meyer1,2, Roland G. Benoit1; 1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2International Max Planck Research School on Neuroscience of Communication
When we experience aversive events, these often turn into unwanted memories. Simple reminders can then trigger the involuntary retrieval of these memories. However, prior evidence indicates that we can also intentionally suppress retrieval to prevent unwanted memories from entering awareness. Such suppression can render memories less vivid and eventually cause forgetting. Here, we test the hypothesis that retrieval suppression weakens memories by compromising their unique neural representations. In an fMRI study, participants memorized associations between reminders and aversive scenes. For some of the reminders, they were instructed to repeatedly suppress the retrieval of the respective scenes. Suppression was associated with increased activation in the right dorsolateral prefrontal cortex and a concomitant decrease in hippocampal activation, a pattern that has been linked to the top-down inhibition of hippocampal retrieval processes. Critically, we assessed the distributed activity patterns of individual memories (as a proxy for their neural representations) both before and after suppression. Using representational similarity analysis, we could thus track changes in the specificity of the neural representations. We observed that memories became less vivid after suppression, and that a stronger decline in vividness was associated with a greater reduction in the specificity of hippocampal memory representations. These preliminary results support the hypothesis that suppression deteriorates memories by compromising their unique neural representations in the hippocampus.
Topic Area: LONG-TERM MEMORY: Episodic