When I was taking PSYC 382, which is taught by Dr. Stephanie Grella, she lectured on memory engrams. I was deeply fascinated by her when she explained how a memory engram works and by her passion for this topic. Recently, Dr. Grella lectured on a much deeper level as to how memory engrams work. I now have the ability to write about a topic similar to memory engrams which has intrigued me for so long. An engram is a physical substrate (brain cells) that were changed when a memory was formed allowing that memory to be stored and retrieved when that memory is needed. Scientists only theorized if engrams even existed and now after years of research we are now not only able to study them but also able to use them to help people going through numerous diseases.
Dr. Grella asked us to read “Memory engrams: Recalling the past and imagining the future” written by Sheena A. Josselyn and Susumu Tonegawa before her lecture where she taught us about engrams on a much deeper scale. Throughout this paper Sheena and Susumu explain how memories are physically stored and retrieved in the brain (an engram) by manipulating engram cells. Researchers used optogenetics and chemogenetics to control engram cells and to manipulate them. They used optogenetics by inserting a specific light activated protein into neurons when a mouse was actively forming a memory. After the mouse was moved to a different place light was shined on those specific neurons which made the mouse experience the same memory as when those specific light proteins were inserted. On the other hand, they were also able to turn memories off completely by silencing the neurons associated with a specific memory. This research article helped prove that engrams not only exist but then they can be manipulated. With this research, we may see in the near future ways to combat specific diseases such as PTSD, Dementia, Amnesia, and even addiction.
In a study done by Christine A Denny et al. titled “From Engrams to Pathologies of the Brain” Denny et al. talks about how understanding memory engrams can help us tackle brain disorders such as previously mentioned PTSD, Dementia, Amnesia, and even addiction. Denny et al. talks about research methods used to study engrams like optogenetics and chemogenetics mentioned earlier. What is also explained is how diseases affect engram formation. Two such diseases being Alzheimer’s disease (AD) and Depression. Denny et al. explains how in AD memories are not destroyed but rather they become silent engrams. Silent engrams are engrams that have weakened connections with other brain regions which leads to normal cues being unable to recall the memory needed. Denny et al. cites other studies that reactivated these lost memories in mice with AD. This goes to show that people with AD may have a chance to regain important memories that were once lost. Next, Denny et al. informs us on how depression focuses on how dysfunctional engrams in dopaminergic areas could contribute to these depressive symptoms. Specifically in the ventral tegmental area which is known for housing dopaminergic neurons has been shown to have a decreased rate of action potentials. Next, Optogenetics was used in mice with depression and activated neurons in the VTA. This reversed the depression-like symptoms in the mice. More research needs to be done, however engrams do seem to have potential as they could help with disorders of the brain.
Overall, both of these articles have shown how far neuroscience and specifically research entailing engrams has gone. Engrams started off as a theory by Richard Sermon and now has been proven and could hold great potential for the future of treatment for neurological conditions. Josselyn and Tonegawa’s research shows how engrams can be identified and manipulated to turn on and off memories. Similarly, Denny et al. informs us on how we can use our knowledge on engrams to tackle complex neurological diseases. Together, these studies show that the future of engram research has a promising future for tackling disorders of the brain.
References
Josselyn, S. A., & Tonegawa, S. (2020). Memory engrams: Recalling the past and imagining the future. Science, 367(6473), eaaw4325. https://doi.org/10.1126/science.aaw4325
No comments:
Post a Comment