Everything is temporary — Neuroscience of Memory Consolidation
We think that humans have the most amazing memory skills among all the species we know of. Some of us even boast ourselves as human supercomputers. Although its the information processing part which contributes more towards the general intelligence, Memory is still a crucial attribute for classifying us as the most intelligent species. But unlike computer chips, human memory is labile in nature and there is a chance for even long term memories to get spoiled. Although this might sound a huge disadvantage, there is a reason why evolution might have kept the impermanence of memories in our brains. But before getting into the philosophical discussions on the same let us get started with how memories are even formed in the first place?
There are many types of memories in our brains, classified according to their purpose. In general, we can group all of them under short term and long term memory. Short Term Memory, which lasts from several seconds to few minutes, can hold items only in a limited capacity. For e.g. on average we can remember around 7 digits when asked randomly for a short duration (although there are techniques like the grouping of digits which give an impression of improved STM, the actual neuroscience explanation for the same is out of scope for this blog). Long Term Memory, is a slightly more complex beast ideally having indefinite capacity, lasting from minutes up to potentially infinite time. An example could be anything from your childhood experiences like that particular adventure with your family and those moments which you can never forget. Now how these memories are formed is the question! And the answer is Consolidation.
Memory consolidation is a process where active short term memories are converted into long term ones. This process could take from minutes to years depending on the complexity of memory. During the consolidation phase, these memories are very fragile in nature and could be easily altered by interference both from outside and internal signals. But once the consolidation phase is over, they aren’t prone to interference and gets stored as LTMs. But the brain is always in a dynamic state and there is always a chance for even LTM to get interfered. LTMs are prone to be spoiled during reconsolidation whenever we actively recall them.
Now this seems a very fragile system and can cause catastrophic forgetting of events that might be very dear to you. But the same weakness of the memory system actually makes it very efficient in terms of life and survival. Imagine we had permanent memories. We could remember everything, each and every scene from the moment we were born to the present time like a movie series. Now if you face a life or death situation, like an earthquake, then would this entire record of life help you at all? Or would it be certain skills you learned during that life, like staying calm and understanding the situation, help you better? In fact, if we remembered everything then we would spend all the time just to search and retrieve the required memory and this would be very inefficient when survival demands real-time responses. Besides who would like to have a balloon head?
Memories actually represent us who we are. Every one of us are unique because we all have walked a unique path in our life no matter who we are. So what if our memories are altered? Would we be a completely different person? I’ll let your mind wander on the same and am sure you will come to a correct conclusion unless someone has already planted false memories in your brain! ; )