take 3

I am here today to do a talk on Memory and the Human brain.

A subject of interest to most of us but still not well understood.
A few quotes

“Memory is the art of time travel.” When we remember things we travel into the past of our mind and bring them forwards into the present.
What is memory?
It is many things, from the  Frank Sinatra “memories are made of this” we learn it is love and good times. From Hiroshima we know it can be death and suffering. Emotions are an important part of the paradigm.  Memory drives our rages and passions, Fills our nights with dreams and our days with nightmares.  We fear to lose it yet some yearn for it to go away.

What is memory?
Scientifically we can describe the components. They consist of input, storage, processing, evaluating and recall. They are the functions of the human brain that enable it to develop consciousness, thought and action. We cannot have one without the other.
A famous quote is “I think, therefore I am“. [Cogito, ergo sum[a] is a Latin philosophical proposition by René Descartes ] but it misses an important codicil, ” I think because I have a memory.”

The brain then is the source and receptacle of memory so we need to start there. A brain was originally part of the blind watchmaker’s  evolutionary design. {The simplest cells survived if a mutation brought about a survival advantage. Being able to detect the environment we live in is an important step forwards.Whether this was an ability to detect sunshine or shade. To feel vibrations from other life forms or to find a partner or food and water at a distance, Sensation was an advantage. As cells became more complex and multi-cellular  function developed so did the senses and specialisation. Nerve cells developed and so did a primitive organising point, the brain.] Each development that makes our memory is reflected in the design of the brain.

Input is by multiple sensory mechanisms, Extroceptive like the 5 senses and temperature, we can also add vibration, position, [proprioception], pain, and visceral sensations [interoception]. This is at least a 3 stage transfer with several neural interfaces before the message reaches  the right area in the cortex of the brain. The neurons in the cortex then also interact with  other cortical neurons that receive the other sensory inputs.The brain is thus awash all over with stimuli and resending of second hand stimuli.

Storage is a mystery. Repetition of signals leads to a stronger memory so changes are recorded and stored by the neurons in the cortices. This may involve changes in the nerve cell  or the axon itself or a more complex feedback loop with the other sensory neurons that are triggered at the same time. We do not know.

Processing happens. Again we do not know but in parallel with the development of Artificial Intelligence we know what might be happening. Memories are stored all over the cortex, not just at the receptors.Memory is also stored and utilised in the other brain structures under the cortex. Theses include the thalamus and the midbrain structures which involve our emotions and our fright or flight reflex.

Recall is the activation of cortex and limbic structures to bring a stored memory back to consciousness.

Here is the true mystery of memory. We have a central processing room in our heads when we think. It builds up a view of the world from our visual memories as if we are the central player looking out on the world. Thought itself though is verbal, in words with an underlay of emotions and visuals. It is an artificial construct. The best way to understand this is with vision The images transmitted to the brain go mainly to the opposite side and are upside down yet our brain sorts all this out into a right side up picture with 3-D effects in a double processing manoeuver.

 

 

 

 

 

 

 

 

 

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