Decoding The Engram

Decoding The Engram

By Vaishnavi Pernenkil

                Have you ever encountered a smell that reminded you of a person, or even a song that makes you reminisce about the past? It seems as if our memory encoding process is one that is unique to every individual, yet recent research by Dr.Chen at John’s Hopkins University states otherwise. Her recent fMRI study where participants were shown the first episode of the BBC show Sherlock and were told to retell their own versions of the same scene, showed that similar areas of the brain lit up when participants were recalling their experiences. This experiment paired with another one done by Sheena Josselyn from the Toronto Hospital for Sick Children try to decode the engram.

The engram, a term coined by the famous psychologist Karl Lashley is a physical trace of a single memory. Karl Lashley was the first psychologist to test lesioning studies in rats and tried to figure out the link between memory encoding and specific regions of the brain. His work focused on lesioning the cortex of rats and testing their ability to solve a maze. This study has now inspired new work regarding specific regions of the brain and memory encoding. A recent study done by Sheena Josselyn, “focused on boosting the memory protein CREB in some cells in the amygdala and showed that those neurons were especially likely to fire when mice learned, and later recalled, a fearful association between auditory tone and foot shocks” (Scientific American). They concluded that eliminating these CREB cells would then allow the animal to forget their fear. They tested this hypothesis by injecting a CREB protein toxin, and when reintroduced to this tone these rats did not show a fear response. This study shows that certain parts of the brain encode memories specifically and, “that there are specific rules by which cells become part of the engram” (Scientific American).

A separate study done by Dr.Chen at John’s Hopkins University tried to follow how memory recall occurs, and what specific regions of the brain are associated with memory recall. This study showed participants the first episode of the BBC show Sherlock and then studied brain activity when these participants recalled the episode. This study concluded that the hippocampus, and the posterior medial cortex lit up in all participants when recalling the first episode of the show, showing that recall patterns are very similar amongst multiple participants.  These studies are paving the way for understanding the engram and are getting close to decoding the engram. It seems as if the way we think are more similar than previously imagined. It is only with the advent of these fMRI studies and curiosity of brilliant minds that we are getting close to understanding how the brain remembers, and how memories are formed.

Works Cited

Shen, Helen. “Portrait of a Memory.” Scientific American, Scientific American, 14 Mar. 2018, www.scientificamerican.com/article/portrait-of-a-memory/.