Monthly Archives: May 2003

Mysteries of the Brain Part – 7


This Veritas was written on Thu, 1 May, 2003

In todays VERITAS we will try to understand why we dream and what we dream about. The study of dreams tells us a lot about how the brain functions.


Dont you find it strange that a thing as perfect as the brain requires 8 hours of rest out of twenty four hours? How much rest does the computer require? So the brain must be doing something really important in sleep.


Dreaming is one of the most important activities that is done during sleep. A normal person starts dreaming about 60-90 minutes after going to sleep. A person who has had less sleep may start dreaming as soon as he sleeps! So the body seems to give a lot of importance to dreaming. This activity has to be done! If a person regularly sleeps less then this activity must be done first!
Researchers have found that during the time we dream parts of our brain are processing information acquired during the day(or the past few days). So the whole brain does not sleep. The information that has been taken in is processed and  the information is stored into memory/discarded depending on its importance.


Now you remember more things than you think you remember. One part of the brain ( the hippocampus) is responsible for declarative or episodic memories. We remember that 2+2 = 4. We know the capital of India is New Delhi. But we also remember how to ride a cycle. We cannot describe it. But we know it. And we can use this kind of information years later. This kind of memory is called implicit memory. It is abstract in nature and you cannot describe it. You may not even know that it exists. This memory  does not reside in the hippocampus.

We cannot use logical thinking to accumulate this kind of information. This is because logic rejects the abstract.When we sleep the logical part of the brain is told to shut up and the experiences gathered during the day are assimilated into different parts of the brain. So when we sleep the day’s images are played back. The logical processing power is turned off. For another part of the brain these images form an experience. Experiencing these images and with no help from logic it tries associate these images with earlier experiences. This forms a story.
Sometimes we remember this story( the story forming is to aid in learning new experiences. It itself need not be remembered). and sometimes not. This is dreaming.


So dreaming forms a link between experiences encountered during the day and the storage of perceptions. We cannot do this during the day because we are too logical then. During dreaming there forms a direct link between the frontal limbic area( responsible for emotion, motivation etc) and the gray cortex at the back of the brain (responsible for perceptions and abstract thinking). The area in the middle(which is responsible for movement and logic) is happily sleeping.


Notice how little importance is given to logical thought. It is a concept which helps us live and avoid trouble. But our personalities have a huge component of the abstract. Processing of the abstract happens when we sleep. If it were done during the day then logic would interfere and not let most of these through. We would no longer be capable of love, hatred, inspiration and other abstract feelings.
What happens when we are dreaming has been sufficiently explained. However a deeper mystery is why we dream a particular sequence and not another. Why we sometimes have scary dreams. What is the relationship between dreams and our personality?
Science does not take away the mystery of a thing by explaining it. It answers some questions but poses deeper ones. So it deepens the mystery. And how can you stay away from mystery. It visits you every night in the form of your dreams!





Go, wondrous creature! mount where Science guides:
Go, measure earth, weigh air, and state the tides:
Instruct the planets in what orbs to run,
Correct old time and regulate the Sun;