Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: Harri on 23/10/2015 22:52:40
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Why can't we remember everything? Is everything that we see and everything that happens to us stored somewhere in our brain?
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The human brain and sensory system has a very impressive form of data compression.
For example, to provide a video display that fills the human visual field with the maximum resolution of human vision would require somewhere around 2Gbps.
However, the processing in the back of the eyeball reduces this to an estimated 100kbps in the optic nerve. It is this compressed data stream that is processed by the brain to recognize people we know, and the child about to step in front of our car.
Similar processing occurs in our ears.
It takes previous experience to recognize these patterns - recognizing a mother's language and food appears to start before birth, and recognizing a mother's face and scent occurs in the first few months after birth.
The human brain does not store a video recording of these data streams, but integrates this with previously stored events. It is thought that this occurs by strengthening certain synaptic links, and weakening others. When we recall an event, our brain fills in the gaps with what "probably" happened, based on the sum total of our previous experiences.
These linkages are not permanent, but are revised every time we recall an event, and the memory can be changed by the context at the time we recall it. This undoubtedly saves a lot of neurones!