Memory Engrams and the chance for Restoration

During the first month of the neuroscience seminar, our lecture hall had the honor of being able to meet one of the scientists that worked on the paper that had great interest to me, a topic that I personally find extremely interesting and one of the reasons I decided to major in Neuroscience: Memory engrams: Recalling the past and imagining the future. Dr. Stephanie Grella introduced the concept of the engram which is beginning to be defined as the unit of measurement for memory. Their research showed ‘gain of function’ and ‘loss of function’ through artificially activating and deactivating target engram cells. This research also found that artificial optogenetic or chemogenetic reactivation of tagged engram cells induced memory expression without the external retrieval cues, as well as serving as a retrieval cue to ‘reawaken’ a dormant engram to induce memory expression.

An article that researches a similar avenue to the previous one; Archive: Drug Reverses Memory Failure Caused by Traumatic Brain Injury, goes more into depth about how scientists have developed a drug that reverses memory impairments caused by traumatic brain injuries(TBI). This drug, ISRIB, allows brain-injured mice to perform as well as control mice, those that do not have any memory impairments whatsoever. This type of external stimulation allows for both new and old synapses to form and reform, causing the brain to function like it had never been impaired. ISRIB itself works by inhibiting the Integrated Stress Response(ISR), and allowing the stressed cells override the ISR and translate into functional proteins at the desired pace. This research pairs Dr Grella in with how external retrieval cues are able to be used to induce memory expression. 

Comparing these two articles side by side, it is still clear to see how the specifics of how memory works, and how it is translated by the brain is still a ‘black box’ problem, not being able to see the inside mechanisms but having to infer. Researchers are still making large strides towards removing this problem, and in the future it may not be a ‘black box’ at all. With Dr. Grella and company’s research, it is becoming more apparent how memory actually works, and how researchers and scientists are able to develop treatment for brain injuries and memory impairments.

Josselyn, Sheena A., and Susumu Tonegawa. “Memory engrams: Recalling the past and imagining the future.” Science, vol. 367, no. 6473, 3 Jan. 2020, https://doi.org/10.1126/science.aaw4325. 

“Archive: Drug Reverses Memory Failure Caused by Traumatic Brain Injury.” Archive: Drug Reverses Memory Failure Caused by Traumatic Brain Injury | UC San Francisco, 7 Oct. 2025, www.ucsf.edu/news/2017/07/407656/drug-reverses-memory-failure-caused-traumatic-brain-injury.