We have talked about dementia and how it affects the brain in respect of memory, so this is how a healthy brain works. Memory is the word used to describe the process involved with retrieval and storage of information, this is a very important process for a person to function in a normal way.

Memories are something that do not actually exist in the same way as say your arm or your leg. It does not have a physical presence but is a concept which refers to the processes of remembering.

Memories are stored as miniscule chemical changes at connecting points between neurons, (which transmit information to specialized cells that transmit signals from the nerves).

Sensory neurons these are able to detect activity from each of the senses and then communicate the information to the interconnecting neurons.

Interconnecting neurons these pass information through the nervous system and also connect to the motor neurons. I think I am imagining a railway line with interchanges here.

Motor neurons, these connect to the muscle tissue and activate them.

Encoding is a biological occurrence that starts with perception. When we meet someone we visually assess them, we listen to the sound of their voice and also we can register how the person smells. These cues put together form our perceptions which are then sent to the hippocampus which files them altogether to make a single experience.

Information is carried by electrical pulses which transfer the information. These pulses contain information which release chemical messengers called neurotransmitters. Every brain cell can form thousands of links like this.

Memory – The brain filters all the information we take in, things that are notable to us are then encoded into the short-term memory, which has a surprisingly low capacity it can only hold about seven items for 20 or 30 seconds at a time. This is where it is filtered to either go in the bin or be filed into the long term memory. With a diseased brain the information fails to make it to the long term memory.

So how complex is the brain, and now we can imagine when the brain gets damaged by a stroke or by Alzheimer’s, what mayhem this must cause. I would liken it to an old fashioned telephone exchange, you dial a number but the telephonist is lazy and just connects any line she fancies, so you never actually speak to the right person.

Such an incredible complex organ but studies on memories are very much in the initial stages and little is known about its working at the molecular level. So, when you get to the top of stairs and can’t remember what you went for, you can blame your short-term memory.