For years scientists believed the formation of memories existed in two cooperative yet independent states — short-term memory and long-term memory. The theory stated that memories existed in short-term memory after their initial creation. Then, the brain would eventually consolidate them into long-term memory and hold them for future recollection.
The neuroscience community believed this method was true, but new science says this isn’t true. Experiments held at the Massachusetts of Institute of Technology (MIT) show the brain creates memories in both short-term and long-term memory at the same time. This work disrupts previously held concepts of memory, and illustrates new methods and uses for memory loss and control.
Memory Work to Remember
For nearly a century, neuroscientists believed short-term memories were created in the hippocampus part of the brain. The hippocampus, located in the medial temporal lobe of the brain, has been shown to have a dramatic effect on short-term memory when injured or destroyed. This observation and several years of testing gave scientists the rationale that short-term memory occurs in the hippocampus, which then moves into the neocortex of the brain, where long-term memory develops.
Short-term memory is detailed and precise, but quickly, and eventually, forgotten to a degree. Long-term memory compensates for this by being able to recall old memories with only limited detail. This is the reason you may remember your childhood birthdays, but not the gifts you received from them.
Neuroscience has always been a slow and cautious science due to ethical and challenging work of experimenting on the brain. After decades of work were researchers able to notice and detect how incorrect this theory was by using optogenetics.
Optogenetics allows for the control of cells through the use of light. In the case of the MIT study, the team of scientists was able to genetically modify cells in mice to produce proteins when subjected to light.
Chemistry of Memories
Neuroscientists discovered that memories physically exist in the brain as a structure of cells. These structures, known as engrams, show researchers how memories move and become active. Unfortunately, because of the multitude of cells in the brain, accounting for vague structures in an active brain was impossible until just recently.
By tagging engrams with light-activated proteins in the brains of genetically modified mice, scientists were able to see the strange relationship between short-term and long-term memory. This relationship
The study conducted at MIT saw a group of mice put through a trail featuring a light electric shock created memories in both the hippocampus and neocortex of the brain. The mice created the memory of the shock in multiple parts of their brains. What’s more, when researchers activated the engrams of the shock in the mice outside the trials, the mice distinctly remembered and reacted to the memory.
Study Into Fading Memories
With this new knowledge in the construction of memories, many questions arise on where memories go when we forget. Diseases like dementia and Alzheimer’s are incredibly difficult to live with and unfortunately affect 5.5 million Americans. Diseases like dementia and Alzheimer’s typically affect those over the age of 65. Alzheimer’s is the sixth-leading killer of the elderly in the United States.
By constructing technologies that better map and activate memories, scientists become one step closer to curing these diseases as well as all memory-related problems. The brain is a challenging organ for researchers to examine or work on. However, with steps like these, it is easy to see new breakthroughs coming in the future.