Why can't we remember our dreams?

Have you ever woken up in the morning filled with the excitement about the dream you had last night but when you try to recall it … you can’t seem to remember a thing? Well you’re not alone. This non-remembrance can often be very frustrating; almost as if the memory of your dream is  just out of reach yet completely unattainable no matter how hard you try. So why do we find it so difficult to remember our dreams?To understand this lets first take a look at the reasons why we sleep. Believe it or not, scientists are still not entirely sure why we need sleep! While there are many differing theories one of the most commonly accepted is that during sleep we are consolidating our memories. We are filtering out the important from the insignificant and consequentially and subconsciously deciding which to keep and which not to keep.Two structures of the brain that are essential in the consolidation of memory are the hippocampus and the neocortex. The hippocampus is an important brain structure essential in the formation of new memories about experienced events. The neocortex is thought to act as a storing unit for these memories where they are permanently stored. For the process of transferring memories from the hippocampus to the neocortex to occur these two parts of the brain are connected through neurons. Now this is where sleep comes into it.Scientists have observed that during deep sleep (or slow wave sleep) both the hippocampus and the neocortex fire electrical signals at precisely the same time. This is often referred to as neural chatter (as if the two parts of the brain are talking to each other), it is thought that this process represents the consolidation of memories. It is during this stage that memories are permanently stored through this transference of memories from the hippocampus to the neocortex. However, during deep sleep we don’t dream.It is during rapid eye movement sleep – REM sleep – that we do dream, however when observing the activity of both the hippocampus and the neocortex it was found that while they both still do fire neurons it is not at the same time (as it is in deep sleep). This seems to suggest that while the memories are being re-created (and sometimes interpreted in our own unique way) in our subconscious minds they are not being stored or transferred to the neocortex. Occasionally however the hippocampus and the neocortex may fire electrical signals through their neurons at the same time (likely be chance), which explains why we remember some dreams – or some aspects of our dreams – and not others.Some research has suggested that we may have approximately 3-5 dreams per night however the majority of us struggle to even remember one. While this may be frustrating it is by no means an uncommon experience. Do you remember many of your dreams? Let us know in the comments below!