Consciously suppressing memories of certain events can cause an amnesiac shadow which can disrupt other unrelated memories. A paper recently published by Michael Anderson and Rik Henson of CBU and Justin Hulbert now at Bard College in Nature Communications showed that deliberately suppressing unwanted memories can lead to amnesia of other events happening near in time to suppression.

The research showed that deliberately disengaging memory retrieval “broadly compromises hippocampal processes” necessary for the creation and stabilization of new memories. As such, continually suppressing the recollection of certain events may prevent the hippocampus from being able to fully encode memories of other experiences.

Previous work has shown that in the aftermath of a traumatic experience, traumatised individuals often show inexplicable forgetting for everyday events, which has been attributed to factors such as stress, loss of sleep, and distraction. However, the amnesic shadow generated intentionally suppressing unwanted memories and disrupting hippocampal activity “constitutes an unrecognized forgetting process that may account for otherwise unexplained memory lapses following trauma.”

http://www.nature.com/ncomms/2016/160315/ncomms11003/abs/ncomms11003.html