Physician's Notebooks 9 - http://physiciansnotebook.blogspot.com - See Homepage
37. Neurology of Memory: Update 20 Septr 2021. The below column shows items in the chapter in order of presentation.
Based on latest data and thinking, memory is not stored in one specific depot in the brain; rather, it is distributed in parts of the cerebral cortex relevant to content (memory of a red hat has the “red” stored in part of occipital lobe for color). Memory is distributed in the sense that there is no cortical center dedicated solely to the storage of memories. Yet memory is localized in the sense that different aspects of events are stored at specific cortical sites—-namely, in the same regions that are specialized to analyze and process what is to be stored.
The study of memory starts with anatomy in the brain but it strives to constantly inform you the reader that it is your brain and your memory and to connect the neurology and the anatomy with practical points to prevent your memory weakness or loss and to make you a memory savant (A specialized genius in memorization).
The Structures in the Brain Involved in Memory:
In the above Figure you are looking into an illustration of a cranium with your left half of the cerebrum removed so as to give the view of the center slice in the right-side of brain. The orbitofrontal cerebral cortex is just above the eye orbit and curves around upward behind the brow and backward on top of the brain to become the prefrontal cortex and continues to become the premotor and motor cortex. Then, continuing back on the top surface of brain, it comes the sensory parietal cortex and, in the rear, the visual occipital cortex. The medial temporal cortex, which contains the hippocampus in its rear part, extends out laterally on left and right sides.
Note the thalamus (labeled; in the full brain, a left and right pair of structures; plural is thalami) and hypothalamus (a single structure beneath and forward of the thalami with left and right symmetry) and, attached by the back-around curve to the hippocampus (labeled). Finally, note the cerebellum, tucked into and under the rear of the brain; it is a single, symmetrical right and left structure.
The working memory (short-term, like RAM memory in your computer) is in the prefrontal cortex. The hippocampus is for longer-term recitative memory called declarative memory. The cerebellum helps in procedural memory of measurements. The basal ganglia is involved in memory as reward and habit.
A memory process can be recopied in left and right sides of the brain. This has practical effect in preventing key memory loss from destructive brain strokes, tumors or surgery. The lesson is: if you need a highly important memory (particularly subject of study or fact that is encompassed in knowledge that extends over space or time or pages of a book) then re study it at intervals so that it will be copy-stored in more than one storage area.
Memory by Habit
The basal ganglia that control habit & outcomes and involve rewards that reinforce good memory are, actually, all the structures named in the above figure under "basal ganglia".
Underview of base of brain; top of the Figure is front of brain and bottom is rear. The amygdalae (plural of amygdala), which work for emotion-related memory are the left-right paired red structures located just inside the medial temporal lobes.
Note that memory involves many structures in the brain; it is not a centralized-by-structure function. Long-term memory in humans is thought to be based on the brain’s growth, including increases in neuronal and synaptic strength an efficiency. Tbis explains infantile amnesia (inability to access infancy memories). Freudian psychoanalytic theory believes the memories are formed but limited to the unconscious from which the analyst by Freudian techniques can extract fhem. Modern knowledge shows that infants (up to at least 1 year) have only a rudimentary capacity for declarative memory based on less developed cerebral cortex. Freud, once again was proved wrong!
Memory involves the input of data - sensory, cognitive (the result of your thinking), emotional and motor - and also the output (the recall process).
Memory starts with sensory input - vision, hearing, touch, etc. You need the prefrontal cortex to organize your sensory input into language and motor recall of skills so that they may be presented for memory and also for paying attention. When we want to dig up something from memory, first we need to identify it by vision or sound and meaning and pay attention to it in our mind's eye.
Memory may be declarative memory in words, like memorizing poem, (which you may bring to consciousness) or it may be procedural memory in your motor system of skills (which you may not access consciously but which you know how to effect —- like how to ride bicycle, how to play violin that do not need words. Declarative memory process is long-term in the hippocampus (a part of the inside temporal lobe of cerebral cortex that is well protected from damage); with repeated memorization it is preserved in many parts of the brain. Procedural memories do not need to be formally memorized. These involve the cerebellum.
Memory by habit:
Then there is the memory that is acquired by keeping outcomes like rewards in your mind, such as a rat being rewarded with food more often when he makes a left at a left-right fork in a road, a memory that depends on habit and is strongly enhanced by being associated with immediate gratification like good food. For example in an experiment a rat is, initially, always rewarded with food when he makes a left turn at the fork in the road, but, after a week, the food location is changed daily, right or left. In such cases most rats will turn left out of habit even though on some days the left does not reward with food. Such outcomes and habit memory depend on the basal ganglia and are strongly enhanced by associating the learning with immediate gratification rewards from the release of dopamine.
A practical point here is to associate your study with a healthy eating reward - to snack with your study. (I do not want to suggest excessive eating so if you are going to follow this advice and read with a snack, it should be considered one of your daily meals and not an addition to your regular eating.) Most of my study reading now is done in sessions where I lightly snack as I read for study and it has made me a kind of idiot savant aka "polymath", a master of all kinds of knowledge, remembering every definition and formula even now at age 88. This works well because the food acts as a reward for your reading and you get into the good habit of liking to read because you know it will be rewarded by good food.
Yogi Berra used to say You can learn an awful lot by studying. And you may learn even more doing it that way.
But also recall in the above-mentioned rat experiment the potential bad effect of adhering to habit. So as you use gratification reward to enhance learning, always at intervals be checking back that your pathway to learning has not suddenly been switched by encountering a new system of ideas, e.g., in 1905 every scientist except Albert Einstein accepted as a basic law of existence, Isaac Newton's (and what even today seems commonsense), that time always flows at an unchanging rate. Einstein was like a very rare experimental rat that used its brain to actually compute all possibilities rather than relying on its basal ganglia habit conditioning. And Einstein won the prize!
Another aspect of memory is its connection to emotion. A high emotion favors remembering but a neutral (blah) feeling favors not remembering. The brain structure that controls that is the amygdala, left and right subcortical structures at the forward base of temporal lobe of cerebral cortex. I use this knowledge by investing strong emotion in important facts or study areas. (For an example, like exclaiming out loud as you memorize the pi constant to 11 digits "Wow! Wow! Wow!)
Also, there is the permanency and transiency of memory and its serial passage through time. Firstly, a memory is a reverberation (like the immediate remembering of a word you voiced a second ago). Such remembering is located in the part of the brain that first records the experience to be remembered - like the visual cerebral cortex for instant flash memory of an image; it is called iconic memory and only exists for seconds in time. But, if the remembering is deemed important to survival, the iconic memory is automatically (without motivation) transiently stored in prefrontal cortex as working memory, the equivalent is the RAM memory of your computer, that in a computer needs to be saved but in a brain may last a minute unless repeated constantly in one's thought or mouthed in which case, the memory can be made relatively permanent - a declarative memory in the hippocampus; and by repeated study the memory can even be recopied in two areas to make it more resistant to loss.
Now let us run a scene memory from its start: You see a familiar face in a crowd; it is Mary your old girlfriend (or it could be Mac your old boyfriend or same sex companion). It is a sudden event and she/he is gone seconds later. The iconic memory is held for a few seconds in time unless the situation - you on a subway platform and a woman whose face you identify as Mary - attracts your subconscious attention because it has had importance in your life; in this case, it sticks in your mind; first, as working memory and, if the memory seems worth keeping longer, it becomes a declarative memory that days later you may recall over a drink with a friend or have a dream about. Then, the initial declarative memory which could last months or years may even further solidify
and made into a permanent memory by reviewing it in your mind with a marker for its importance later.
If we analyze the memory and try to locate it as it goes through your brain's anatomy, first we come up with the vision of Mary's face - iconic memory. Here it needs your attention. Normally you go through life with many instant scenes flashing by. But you only remember when something in the scene provokes your attention. Here it is Mary's face with all the emotional, sexual, intellectual feeling history that goes with it. This is an automatic attention response, a bottom-up response that pinpoints important scenes you may need to make a memory of and recall later. But you may improve this by making a special note of a potential iconic memory, e.g., as you swallow your important morning pill, or flush a toilet you just defecated into, or etc., by making a mental note like saying "Aha, I just swallowed my morning pill or I just ....!"
That is the start of many memories. Other memories may start as part of a routine - like your memorizing a poem to recite in class. The previously mentioned automatic attention response like, to Mary's face, is bottom-up (inherent in the image - like a single green ball in a group of red balls; or like Mary's face in a group of otherwise non familiar women's faces). The voluntary memory is top-down (i.e., your cerebral cortex decides based on feedback from past memories - top-down - to remember a poem you will recite in class tomorrow).
Just as initial attention selects a scene for your memory, so a more determined attention selects whether or not a working memory will be transferred to the hippocampus for more permanent processing. If one keeps alert to the importance of a working memory in one's life, one may consciously direct it for more processing by making a further mental note, or actually speaking the item with one's lips or out loud, or writing it down for emphasis. (An old fashioned method was to tie a string around one's finger to keep important working memory for more than the usual few minutes so it could be registered in hippocampus as more permanent declarative memory.)
Once in the hippocampus, a declarative memory is relatively permanent but it may be lost by physical damage to the area. And also as we discuss, its recall may become rusty with time.
Again, a permanent memory access may be in more than one place in the brain - both left and right hippocampus, or some other nearby area of medial temporal lobe. This is the benefit of renewing a memory of an important piece of data; re memorizing. It also happens when you constantly re study written material. In this case, a stroke in one area will not erase the important information.
The cerebellum is important in timing. I trained myself to remember the cerebellar timing mechanism; so much so that I can coincide my interval glances at my cell phone's time and almost always be right to the exact minute. Another type of cerebellar memory is your fingers remembering a door- or safe-opening combination of numbers that you press in sequence to get into your apartment lobby of safe box. You will find, initially, that you may memorize the number sequence in a declarative memory way (Your hippocampus). But after time passes with continued pressing of the numbers you will find your fingers remember the numbers so that you do not have to even think of the numbers; you just allow your fingers to press. That is a cerebellar memory - completely non verbal. (But you also retain a copy of the same combination by declarative memory in hippocampus; again an important protection against losing a memory by a brain stroke or other local brain damage)
37. Neurology of Memory: Update 20 Septr 2021. The below column shows items in the chapter in order of presentation.
Memory is not stored in
The study of memory starts with anatomy in the brain
The Structures of the Brain Involved in Memory
Declarative memory
Procedural memory
Memory by habit
Infantile amnesia
associate your study with a healthy eating reward
Its connection to emotion
The permanency and transiency of memory
Run a scene memory from its start
Iconic memory
The cerebellum
The Electro-chemical Aspect of Memories
Prevent physical damage memory loss
The electro-chemical aspect of memories
Techniques of recall
Anomia
Memory Distortion
Memories and the Unconscious
Become an idiot savant of memory
The Structures of the Brain Involved in Memory
Declarative memory
Procedural memory
Memory by habit
Infantile amnesia
associate your study with a healthy eating reward
Its connection to emotion
The permanency and transiency of memory
Run a scene memory from its start
Iconic memory
The cerebellum
The Electro-chemical Aspect of Memories
Prevent physical damage memory loss
The electro-chemical aspect of memories
Techniques of recall
Anomia
Memory Distortion
Memories and the Unconscious
Become an idiot savant of memory
The study of memory starts with anatomy in the brain but it strives to constantly inform you the reader that it is your brain and your memory and to connect the neurology and the anatomy with practical points to prevent your memory weakness or loss and to make you a memory savant (A specialized genius in memorization).
The Structures in the Brain Involved in Memory:
In the above Figure you are looking into an illustration of a cranium with your left half of the cerebrum removed so as to give the view of the center slice in the right-side of brain. The orbitofrontal cerebral cortex is just above the eye orbit and curves around upward behind the brow and backward on top of the brain to become the prefrontal cortex and continues to become the premotor and motor cortex. Then, continuing back on the top surface of brain, it comes the sensory parietal cortex and, in the rear, the visual occipital cortex. The medial temporal cortex, which contains the hippocampus in its rear part, extends out laterally on left and right sides.
Note the thalamus (labeled; in the full brain, a left and right pair of structures; plural is thalami) and hypothalamus (a single structure beneath and forward of the thalami with left and right symmetry) and, attached by the back-around curve to the hippocampus (labeled). Finally, note the cerebellum, tucked into and under the rear of the brain; it is a single, symmetrical right and left structure.
The working memory (short-term, like RAM memory in your computer) is in the prefrontal cortex. The hippocampus is for longer-term recitative memory called declarative memory. The cerebellum helps in procedural memory of measurements. The basal ganglia is involved in memory as reward and habit.
A memory process can be recopied in left and right sides of the brain. This has practical effect in preventing key memory loss from destructive brain strokes, tumors or surgery. The lesson is: if you need a highly important memory (particularly subject of study or fact that is encompassed in knowledge that extends over space or time or pages of a book) then re study it at intervals so that it will be copy-stored in more than one storage area.
Memory by HabitThe basal ganglia that control habit & outcomes and involve rewards that reinforce good memory are, actually, all the structures named in the above figure under "basal ganglia".
| Brain: Amygdala | |
|---|---|
 |
Note that memory involves many structures in the brain; it is not a centralized-by-structure function. Long-term memory in humans is thought to be based on the brain’s growth, including increases in neuronal and synaptic strength an efficiency. Tbis explains infantile amnesia (inability to access infancy memories). Freudian psychoanalytic theory believes the memories are formed but limited to the unconscious from which the analyst by Freudian techniques can extract fhem. Modern knowledge shows that infants (up to at least 1 year) have only a rudimentary capacity for declarative memory based on less developed cerebral cortex. Freud, once again was proved wrong!
Memory involves the input of data - sensory, cognitive (the result of your thinking), emotional and motor - and also the output (the recall process).
Memory starts with sensory input - vision, hearing, touch, etc. You need the prefrontal cortex to organize your sensory input into language and motor recall of skills so that they may be presented for memory and also for paying attention. When we want to dig up something from memory, first we need to identify it by vision or sound and meaning and pay attention to it in our mind's eye.
Memory may be declarative memory in words, like memorizing poem, (which you may bring to consciousness) or it may be procedural memory in your motor system of skills (which you may not access consciously but which you know how to effect —- like how to ride bicycle, how to play violin that do not need words. Declarative memory process is long-term in the hippocampus (a part of the inside temporal lobe of cerebral cortex that is well protected from damage); with repeated memorization it is preserved in many parts of the brain. Procedural memories do not need to be formally memorized. These involve the cerebellum.
Memory by habit:
Then there is the memory that is acquired by keeping outcomes like rewards in your mind, such as a rat being rewarded with food more often when he makes a left at a left-right fork in a road, a memory that depends on habit and is strongly enhanced by being associated with immediate gratification like good food. For example in an experiment a rat is, initially, always rewarded with food when he makes a left turn at the fork in the road, but, after a week, the food location is changed daily, right or left. In such cases most rats will turn left out of habit even though on some days the left does not reward with food. Such outcomes and habit memory depend on the basal ganglia and are strongly enhanced by associating the learning with immediate gratification rewards from the release of dopamine.
A practical point here is to associate your study with a healthy eating reward - to snack with your study. (I do not want to suggest excessive eating so if you are going to follow this advice and read with a snack, it should be considered one of your daily meals and not an addition to your regular eating.) Most of my study reading now is done in sessions where I lightly snack as I read for study and it has made me a kind of idiot savant aka "polymath", a master of all kinds of knowledge, remembering every definition and formula even now at age 88. This works well because the food acts as a reward for your reading and you get into the good habit of liking to read because you know it will be rewarded by good food.
Yogi Berra used to say You can learn an awful lot by studying. And you may learn even more doing it that way.
But also recall in the above-mentioned rat experiment the potential bad effect of adhering to habit. So as you use gratification reward to enhance learning, always at intervals be checking back that your pathway to learning has not suddenly been switched by encountering a new system of ideas, e.g., in 1905 every scientist except Albert Einstein accepted as a basic law of existence, Isaac Newton's (and what even today seems commonsense), that time always flows at an unchanging rate. Einstein was like a very rare experimental rat that used its brain to actually compute all possibilities rather than relying on its basal ganglia habit conditioning. And Einstein won the prize!
Another aspect of memory is its connection to emotion. A high emotion favors remembering but a neutral (blah) feeling favors not remembering. The brain structure that controls that is the amygdala, left and right subcortical structures at the forward base of temporal lobe of cerebral cortex. I use this knowledge by investing strong emotion in important facts or study areas. (For an example, like exclaiming out loud as you memorize the pi constant to 11 digits "Wow! Wow! Wow!)
Also, there is the permanency and transiency of memory and its serial passage through time. Firstly, a memory is a reverberation (like the immediate remembering of a word you voiced a second ago). Such remembering is located in the part of the brain that first records the experience to be remembered - like the visual cerebral cortex for instant flash memory of an image; it is called iconic memory and only exists for seconds in time. But, if the remembering is deemed important to survival, the iconic memory is automatically (without motivation) transiently stored in prefrontal cortex as working memory, the equivalent is the RAM memory of your computer, that in a computer needs to be saved but in a brain may last a minute unless repeated constantly in one's thought or mouthed in which case, the memory can be made relatively permanent - a declarative memory in the hippocampus; and by repeated study the memory can even be recopied in two areas to make it more resistant to loss.
Now let us run a scene memory from its start: You see a familiar face in a crowd; it is Mary your old girlfriend (or it could be Mac your old boyfriend or same sex companion). It is a sudden event and she/he is gone seconds later. The iconic memory is held for a few seconds in time unless the situation - you on a subway platform and a woman whose face you identify as Mary - attracts your subconscious attention because it has had importance in your life; in this case, it sticks in your mind; first, as working memory and, if the memory seems worth keeping longer, it becomes a declarative memory that days later you may recall over a drink with a friend or have a dream about. Then, the initial declarative memory which could last months or years may even further solidify
and made into a permanent memory by reviewing it in your mind with a marker for its importance later.
If we analyze the memory and try to locate it as it goes through your brain's anatomy, first we come up with the vision of Mary's face - iconic memory. Here it needs your attention. Normally you go through life with many instant scenes flashing by. But you only remember when something in the scene provokes your attention. Here it is Mary's face with all the emotional, sexual, intellectual feeling history that goes with it. This is an automatic attention response, a bottom-up response that pinpoints important scenes you may need to make a memory of and recall later. But you may improve this by making a special note of a potential iconic memory, e.g., as you swallow your important morning pill, or flush a toilet you just defecated into, or etc., by making a mental note like saying "Aha, I just swallowed my morning pill or I just ....!"
That is the start of many memories. Other memories may start as part of a routine - like your memorizing a poem to recite in class. The previously mentioned automatic attention response like, to Mary's face, is bottom-up (inherent in the image - like a single green ball in a group of red balls; or like Mary's face in a group of otherwise non familiar women's faces). The voluntary memory is top-down (i.e., your cerebral cortex decides based on feedback from past memories - top-down - to remember a poem you will recite in class tomorrow).
Just as initial attention selects a scene for your memory, so a more determined attention selects whether or not a working memory will be transferred to the hippocampus for more permanent processing. If one keeps alert to the importance of a working memory in one's life, one may consciously direct it for more processing by making a further mental note, or actually speaking the item with one's lips or out loud, or writing it down for emphasis. (An old fashioned method was to tie a string around one's finger to keep important working memory for more than the usual few minutes so it could be registered in hippocampus as more permanent declarative memory.)
Once in the hippocampus, a declarative memory is relatively permanent but it may be lost by physical damage to the area. And also as we discuss, its recall may become rusty with time.
Again, a permanent memory access may be in more than one place in the brain - both left and right hippocampus, or some other nearby area of medial temporal lobe. This is the benefit of renewing a memory of an important piece of data; re memorizing. It also happens when you constantly re study written material. In this case, a stroke in one area will not erase the important information.
The cerebellum is important in timing. I trained myself to remember the cerebellar timing mechanism; so much so that I can coincide my interval glances at my cell phone's time and almost always be right to the exact minute. Another type of cerebellar memory is your fingers remembering a door- or safe-opening combination of numbers that you press in sequence to get into your apartment lobby of safe box. You will find, initially, that you may memorize the number sequence in a declarative memory way (Your hippocampus). But after time passes with continued pressing of the numbers you will find your fingers remember the numbers so that you do not have to even think of the numbers; you just allow your fingers to press. That is a cerebellar memory - completely non verbal. (But you also retain a copy of the same combination by declarative memory in hippocampus; again an important protection against losing a memory by a brain stroke or other local brain damage)
The electro-chemical aspect of memories is also important. Repeatedly renewing a memory strengthens the synapse connecting neuron to neuron and this is how memorization gets effected. Also it explains why the electric shock treatment to the brain (popular to treat severe depressions and psychoses) affects memory.
Preventing physical damage memory loss:
Not enough is known to repair physical-damage memory loss. (Of course keep good personal, written or computer records!) But we can prevent it by lowering blood cholesterol, moderating alcohol intake, keeping blood pressure normal healthy low, avoiding tranquilizers and corticosteroids, except for good medical indication and for limited courses. Also we can improve recall memory skills.
Up to here, memory input has been discussed but the practical issue most of the time is output. You may retain a memory for life in several parts of the brain, but if you cannot bring it to conscious recall, it is, in a practical sense, forgotten. Here is the place of techniques of recall and for that click 1.8 Secrets of Memory/Digit Memory System and read it. Today, at age 88, I can recall 20-digit numbers at a glance because I have mastered the techniques which rise above the anatomy and aging.
Anomia: I sometimes have difficulty recalling a common name of something or someone I knew but have not recalled recently. Almost always in those cases, given time or the use of recall techniques, the difficult-to-recall name pops up into my memory, which proves that most "forgettings" are not lost memories but simply difficult-to-recall memories and the difficulty is due to defective nerve fiber connections that worsen with old age. This is useful knowledge because it points an older person toward techniques of recall that are in the Notebooks 1 chapter.
Memory Distortion: How much can one’s memories be trusted? Experiments have proven it is possible for one to confidently remember events that never happened. Much depends on the person, the timing and the motivation. A single memory should never be absolutely trusted. Have humility about that fact and if it is on an important issue always insist on corroboration but 3rd party or other ways.
Not enough is known to repair physical-damage memory loss. (Of course keep good personal, written or computer records!) But we can prevent it by lowering blood cholesterol, moderating alcohol intake, keeping blood pressure normal healthy low, avoiding tranquilizers and corticosteroids, except for good medical indication and for limited courses. Also we can improve recall memory skills.
Up to here, memory input has been discussed but the practical issue most of the time is output. You may retain a memory for life in several parts of the brain, but if you cannot bring it to conscious recall, it is, in a practical sense, forgotten. Here is the place of techniques of recall and for that click 1.8 Secrets of Memory/Digit Memory System and read it. Today, at age 88, I can recall 20-digit numbers at a glance because I have mastered the techniques which rise above the anatomy and aging.
Anomia: I sometimes have difficulty recalling a common name of something or someone I knew but have not recalled recently. Almost always in those cases, given time or the use of recall techniques, the difficult-to-recall name pops up into my memory, which proves that most "forgettings" are not lost memories but simply difficult-to-recall memories and the difficulty is due to defective nerve fiber connections that worsen with old age. This is useful knowledge because it points an older person toward techniques of recall that are in the Notebooks 1 chapter.
Memory Distortion: How much can one’s memories be trusted? Experiments have proven it is possible for one to confidently remember events that never happened. Much depends on the person, the timing and the motivation. A single memory should never be absolutely trusted. Have humility about that fact and if it is on an important issue always insist on corroboration but 3rd party or other ways.
Memories and the Unconscious: the modern biological view distinguishes between memories that can be brought to mind—-declarative conscious memories—and unconscious memories that need to be accessed by techniques like hypnosis or drugs. Non-declarative memories may be expressed thru performance—-like driving a car. In this view one’s behavior may be the affects of early life but the effects may be in personality dispositions and not from conscious understanding, i.e.,the Freudian oedipus hypothesis.
Now that this chapter has given you this hint, start working on the idea of using your attention mode, using your emotion mode, using rewards of instant gratification, paying attention to habit learning; and mastering the recall techniques and you may become an idiot savant of memory, as I have, and reap all kinds of benefits in your life.
End of Chapter. To read next, click 9.(38-40) Hypothalamus -Body Clock,Glands, Sexual...
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