New Discoveries on Optimizing Memory Formation

As each of us goes through life, we remember a little and forget a lot. The stockpile of what we remember contributes greatly to define us and our place in the world. Thus, it is important to remember and optimize the processes that make that possible.

People who compete in memory contests (“memory athletes”) have long known the value of associational cues (see my Memory Power 101 book). Neuroscientists have known for a long time about memory consolidation (converting short-term memory to long-term form) and the value of associational cues. But now, important new understanding is arising from a research lab at Northwestern that links cueing to “re-consolidation” and reveals new possibilities for optimizing long-term memory formation.

The underlying research approach is based on such well-established memory principles as:

1. When information is first acquired, it is tagged for its potential importance or value.
2. Such tagging is influenced by multiple factors such as repetition, attention, emotion, or purpose.
3. Valuable memories get preferentially rehearsed, either through conscious will or by covert (implicit) brain processes.
4. Rehearsal episodes reactive the memory and enhance long-term remembering because each re-consolidation episode builds on prior ones and strengthens the neural circuits that store the memory.
5. Effectiveness of recall during rehearsal is promoted by use of relevant cues, that is, information that was associated with the original learning material.
6. Such cues are effective, even when delivered during sleep.[1]

The study involved 60 people in their early 20s, screened for good memory ability.[2] All subjects participated in a four-hour learning period beginning in late morning. The learning consisted of 72 images placed in specific locations on a tile-like screen and presented one at a time. As each image appeared a corresponding sound was associated, intended to serve as a learning cue. For example, a dog picture would be associated with barking, cat with meow sound, etc. To create a value bias, each image had a superimposed number representing how important it was to remember this item and its location upon later testing. Subjects were given financial reward for how well they remembered, and thus remembering high-value images was a priority. Half of the images had high value assignments, while the rest had low values.

 Subjects were assigned to four groups:  

1. Groups 1 and 2 were tested to see how well they could remember where each object had appeared during the learning phase. They then took a 90 min nap while their EEGs were recorded. Half of these subjects heard white noise while the other have was presented the original sound cues of low-value images during non-REM sleep at a level that did not cause awakening. At the end of the nap, recall was again tested.
2. The procedure in two other groups was similar except that these subjects did not nap. One of these groups watched a movie during the 90 minutes after the learning session, while the other group listed to the low-value sound cues while performing a working memory task.

Not surprisingly, the studies revealed that high-value images were remembered better, irrespective of whether or not a nap was taken. The practical point is that we remember better the things we value and find to have positive reward value. This reminds me of the sage saying that T. Boone Pickens repeated from his basketball coach, who told players after each game: “Don’t dwell on your mistakes. Think about what you did right and do more of that!”

In the study, half of the low-value associations were rescued by cueing during wakefulness and all of them were rescued by cueing during sleep, even though only half of the images were cued. Notably, the best effects occurred during the deepest stage of sleep. No explanation was given to explain the sleep benefit, but I suspect it is because the sleeping brain is not distracting itself with irrelevant thoughts. This is consistent with the finding that low-value memories were not rescued well during REM sleep, when the brain is busily engaged in dreaming. The REM-sleep finding is at variance with other studies that reported a memory consolidating benefit of REM sleep. Apparently, the test conditions make a difference and more research is needed here.

Low-value associations were preferentially forgotten in the group that was not allowed to nap. This likely signifies that a brain busily engaged with other thoughts is less able to selectively consolidate memories, and only high-value items are likely to survive. This accords with the long-held theory that distractions and multi-tasking interfere with memory consolidation.

In summary, memory optimization would seem to require one to:

1.    Create associations that can serve as memory cues.

2.    Place a high value on the cues and their targets.

3.    Repeatedly present the cues and replay the initial information. When awake, present the cues in self-test mode. When asleep, even better results would obtain if cues were presented at a level that does not cause awakening during the early night sleep when sleep is deepest and there is little dreaming.

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1. Antony, J. W, Gobel, E. W., O’Hare, J., K., Reber, P. J., and Paller, K. A. (2012). Cued memory reactivation during sleep influences skill learning. Nat. Neurosci. 15: 1114:1116. Rudoy, J. D., Voss, J. L., Westerberg, C. E., Paller, K. A. (2009). Strengthening individual memories by reactivating them during sleep. Science. 326: 1079.

2. Oudiette, D., Antony, J. W., Creery, J. D., and Paller, K. A. (2013) The role of memory reactivation during wakefulness and sleep in determining which memories endure. J. Neurosci. 33(15): 6672-6678.

Don't forget to check my memory e-book, Better Grades, Less Effort, 

for only $2.99 at Smashwords.com.

10 Ways to Make Memory Rehab Work

Physical exercise can rehabilitate bodies that have grown soft and flabby. Can mental exercise rehabilitate brains that have deteriorated because of disease or age? Maybe.

A published scholarly review has examined the research literature on this issue and arrived at several useful conclusions:

1.      Focus, Reduce Distractions. The two common causes of forgetting, in both normal people and those with impaired memory, are a) failure to register new information effectively, and b) interference from conflicting sensations and thoughts.

2.      Customize the Rehabilitation Needed. Rehab need to take into account the type of memory therapy and the cause and severity of the impaired memory capability.

3.      Learn in Small, Frequently Repeated Chunks. New information has to be re-packaged for memory-impaired people so that it is in simple, concrete form, in small chunks, and repeated frequently — with patients required to re-state the information and make explicit associations with what they already know. (Notice how this sounds like the way one needs to teach young children).

4.      Practice Attentiveness. Attentiveness to new information can be enhanced by self-cueing, wherein patients remind themselves to be more attentive at crucial moments. This can even be done by creating a conditioned reflex in which a cue signal conditions greater attentiveness. (Notice how this sounds like how you “clicker” train dogs).

5.      Uses Mnemonics. Mnemonic tips and tricks can help. This includes using acronyms, rhymes, stories, and constructing mental images.

6.      Find Ways to Compensate. Even in patients with severe impairments, some aspects of memory, such as subliminal or implicit memory, may have been spared and can be exploited to compensate for the lost ability.

7.      Spread Rehearsals Over Time. Memory rehearsal is more effective if it is spread out over time rather than bunched into a few closely spaced sessions.

8.      Manipulate the Cues. Be more aware of cues you are using. A “vanishing clues” approach can help. For example, in a rehearsal session, cued retrieval might begin with cueing the first three letters of a target word, then repeating later with two, then  one, and eventually no letter cues.

9.      Minimize Error, Lest you Learn the Errors. Trial-and-error learning is generally less effective than learning conditions that minimize error, because error responses can get stored as memories that compete with the right answers. In short, it is better to not know than to generate wrong answers.

10.  Use Memory Crutches. Using external memory aids (sticky notes, wall charts, notebooks, etc.) should help, bearing in mind, however, that using such aids may themselves be a memory task. It is like having a schedule calendar and forgetting to check the calendar. Smart phones and radio paging devices (“NeuroPage”) can be especially helpful because they remind the patient when to check on the stored information. In some patients, repeated use of such aids develops a habit for target tasks and these may even generalize to certain non-target tasks.

These ten approaches are some of the same approaches that work especially well in people with normal memory capabilities. To make them work in patients with impaired memory just takes more effort, patience, and time.

Source: Ptak, R., Van der Linden, M., and Schneider, A. 2010. Cognitive rehabilitation of episodic memory disorders: from theory to practice. Frontiers in Human Research. 4 (57): 1-11. doi: 10.3389/fnhum.2010.00057.

Getting Out of a Rut

Why is it so hard to change behavior, or attitudes, or personality? I’ll tell you why. These things are habits. Habits are well learned and they persist from mindlessness.

Our behavior, attitudes, and personality are predisposed by genetics but also ingrained by repeating and reinforcing them over long periods. Thus, the older you get the more inflexible you get. But I see teenagers stuck in ruts too, and they are less likely to have the fronto-parietal cortex executive control to impose changes on themselves.

Regardless of age, being in a rut comes from learning to the point of creating a habit. Habits are really hard to change. Wendy Wood, in her review of the recent book, The Power of Habit, points out that contextual cues trigger habitual behavior. In other words, when you are in a rut, you have mindlessly outsourced your brain’s executive control to these cues. You run on auto-pilot. It is easier to respond to such cues reflexively than think about it and do something else.

Cures for reforming habits require attention to the triggering cues as the core of self-control strategies. When an unwanted response is activated from memory, it needs to be inhibited. Bad habits, unlike responses to temptations, are controlled most effectively through spontaneous introspective awareness and executive control (“Why am I doing this?”…“I don’t want to be doing this”… “don’t do it”… “am I backsliding?”) Vigilant self-awareness and monitoring apparently do not change the strength of the habit memory but are effective because they enhance executive control processes. Wood suggests that the most promising way to break a habit is to “disrupting habit cues so that the old response is not brought to mind and new habits can be learned.”

Some examples of cue awareness and disruption include:

1.    If you over-eat, use smaller plates or put smaller helpings on the plate.

2.    If you can’t focus and your mind wanders, notice distractions for what they are. Practice meditation.

3.    If you are hyper-critical or argumentative, recognize the instant you disagree.

4.    If you are lazy, be aware of your environment when you aren’t doing anything.

5.    If you are boastful, notice the situation that makes you want to boast.

If you want to get out of a rut, another important aid is to substitute a new and more desirable habit. I learned this years ago when I tried to quit smoking. I succeeded many times—in other words, I failed to really quit. Only when I decided to take up jogging and forced myself to do it persistently, was I able to substitute the positive reinforcement of nicotine with the positive reinforcement of the endorphins that are released during jogging.

To substitute a better habit, you must pick something that is likewise reinforcing and repeat it enough for it to become a habit. It also helps to simultaneously remove the cues that trigger the old bad habit. For example, when I finally quit smoking, I made myself go jog when I had a strong urge to smoke. Even though I had an urge to smoke many times a day yet only jogged once daily, this single substitution act seemed sufficiently helpful.

Some examples of habit substitution include:

1.    If you eat more meat than you want, find tasty vegetarian menus.

2.    If you gossip, restrict all gossip to praise talk.

3.    If you procrastinate, create a habit of doing the hard things first.

4.    If you whine, make yourself provide positive interpretations.

5.    If you associate with people who are dragging you down, spend more time with new associates who can lift you up.

Finally, we have to stop making excuses. Our usual attempts to blame things on “bad genes,” are misleading. In recent years, scientists have discovered that most of our DNA does not have a coding function. They used to call it “junk” DNA, presumably just carried along as useless sludge in the stream of evolution. Now they discover that “junk DNA” actually controls the expression of the coding genes. New discoveries in the field of “epigenetics” are showing that what we think and do influence if and when many of our coding genes are expressed.

Sources:

Klemm, W. R. (2008) Blame Game. How to Win It. Bryan, Tx: Benecton Press.

Quinn, J. M., Pascoe, A., Wood, Wendy, and Neal, D. T. (2010) Can’t control yourself? Monitor those bad habits. Personality and Social Psychology Bulletin. 36(4); 499-511 doi: 10.1177/0146167209360665

Wood, Wendy (2013) On ruts and getting out of them. Science. 336: 980-981

Improving Motivation to Learn

When it comes to improving learning and memory, motivation is way ahead of whatever is in second place. From my own experience and from observing hundreds of students, it is clear to me that people will learn when they WANT to learn. Even in the face of bad textbooks, bad schools, bad teachers, … whatever, motivated students will learn. If people with few learning resources, like Booker T. Washington or Abe Lincoln could do it in their day, our kids can certainly do it with all the information available in the millions of books in public libraries and web sites on the Internet.

One of my blog readers called my attention to a recent post on NannyPro.com web site, entitled “24 Blogs Filled with Ideas on How to Motivate Your Kids to Finish the School Year Strong.” As author Michelle points out, motivation of students in school commonly falls in the Spring sinkhole of Spring break and end-of-year doldrums.

Advice to parents includes specific ways to set goals, tips for getting kids to do homework, and ideas for pumping up motivation. Michelle’s blog has links to other useful sites. Those I checked that looked promising to me included one on “21 Simple Ideas to Improve Student Motivation.” Another helpful site is titled “Reward Effort Before Test Day.” Other site topics you might want to check out include:

•         “Homework That Motivates”
•          “Lighting A Fire: Motivating Boys To Succeed”
•       "The Secret of Setting Successful Goals”
•       “Top Tips: Getting kids to do their homework”

Michelle also lists some ideas for schools to do. Parents ought to take a look at these and make suggestions that could be appropriate for their local school.

If you haven’t gotten your child a copy of my “Better Grades, Less Effort” you have denied them of a possible school-life-changing opportunity. It may be the best $2.99 you ever spent.

Cursive Writing Makes Kids Smarter

Ever try to read your physician’s prescriptions? Children increasingly print their writing because they don’t know cursive or theirs is unreadable. I have a middle-school grandson who has trouble reading his own cursive. Grandparents may find that their grandchildren can’t read the notes they send. Our new U.S. Secretary of the Treasury can’t (or won’t) write his own name on the new money being printed.

When we adults went to school, one of the first things we learned was how to write the alphabet, in caps and lower case, and then to hand-write words, sentences, paragraphs, and essays. Some of us were lucky enough to have penmanship class where we learned how to make our writing pretty and readable. Today, keyboarding is in, the Common Core Standards no longer require elementary students to learn cursive, and some schools are dropping the teaching of cursive, dismissing it as an “ancient skill.”[1]

The primary schools that teach handwriting spend only just over an hour a week, according to Zaner-Bloser Inc., one of the nation's largest handwriting-curriculum publishers. Cursive is not generally taught after the third grade (my penmanship class was in the 7^th grade; maybe its just coincidence, but the 7^th grade was when I was magically transformed from a poor student into an exceptional student).

Yet scientists are discovering that learning cursive is an important tool for cognitive development, particularly in training the brain to learn “functional specialization,”[2] that is capacity for optimal efficiency. In the case of learning cursive writing, the brain develops functional specialization that integrates both sensation, movement control, and thinking. Brain imaging studies reveal that multiple areas of brain become co-activated during learning of cursive writing of pseudo-letters, as opposed to typing or just visual practice.

There is spill-over benefit for thinking skills used in reading and writing. To write legible cursive, fine motor control is needed over the fingers. Students have to pay attention and think about what and how they are doing. They have to practice. Brain imaging studies show that cursive activates areas of the brain that are not affected by keyboarding.

Much of the benefit of cursive writing comes simply from the self-generated mechanics of hand- printing letters. During one study at Indiana University to be published this year,[3] researchers conducted brain scans on pre-literate 5-year olds before and after receiving different letter-learning instruction. In children who had practiced self-generated printing by hand, the neural activity was far more enhanced and "adult-like" than in those who had simply looked at letters. The brain’s “reading circuit” of linked regions that are activated during reading was activated during cursive writing, but not during typing. This lab has also demonstrated that writing letters in meaningful context, as opposed to just writing them as drawing objects, produced much more robust activation of many areas in both hemispheres.

In learning to write by hand, even if it is just printing, a child’s brain must:

•            Locate each stroke relative to other strokes.
•            Learn and remember appropriate size, slant of global form, and feature detail characteristic of each letter.
•       Develop categorization skills.

Cursive writing, compared to printing, is even more beneficial because the movement tasks are more demanding, the letters are less stereotypical, and the visual recognition requirements create a broader repertoire of letter representation. Cursive is also faster and more likely to engage students by providing a better sense of personal style and ownership.

Other research highlights the hand's unique relationship with the brain when it comes to composing thoughts and ideas. Virginia Berninger, a professor at the University of Washington, reported her study of children in grades two, four and six that revealed they wrote more words, faster, and expressed more ideas when writing essays by hand versus with a keyboard.[4]

There is a whole field of research known as “haptics,” which includes the interactions of touch, hand movements, and brain function.[5] Cursive writing helps train the brain to integrate visual, and tactile information, and fine motor dexterity. School systems, driven by ill-informed ideologues and federal mandate, are becoming obsessed with testing knowledge at the expense of training kids to develop better capacity for acquiring knowledge.

The benefits to brain development are similar to what you get with learning to play a musical instrument. Not everybody can afford music lessons, but everybody has access to pencil and paper. Not everybody can afford a computer for their kids−maybe such kids are not as deprived as we would think.

Take heart. Some schools just celebrated National Handwriting Day on Jan. 23. Cursive is not dead yet. Parents need to insist that cursive be maintained in their local school.

Readers who want an easy way to acquire a neuroscience background will want to know about the 2nd Edition of my e-book, “Core Ideas in Neuroscience.” Check my web site for available formats and sources (thankyoubrain.com/neurobook). Also check out the Neuro-education discussion group I just created on Linkedin (type “Neuro-education" in Linkedin’s search field).

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[1] Slape, L. “Cursive Giving Way to Other Pursuits as Educators Debate Its Value.” The Daily News, Feb. 4,

2012. http://tdn.com/news/local/cursive-giving-way-to-other-pursuits-as-educators-debate-its/article_c0302938-4f94-11e1-af3a-0019bb2963f4.html

[2] James, Karin H. an Atwood, Thea P. (2009).The role of sensorimotor learning in the perception of letter-like forms: Tracking the causes of neural specialization for letters. Cognitive Neuropsychology.26 (1), 91-100.

[3] James, K.H. and Engelhardt, L. (2013). The effects of handwriting experience on functional brain

development in pre-literate children. Trends in Neuroscience and Education. Article in press.

[4] Berninger, V. “Evidence-Based, Developmentally Appropriate Writing Skills K–5: Teaching the

Orthographic Loop of Working Memory to Write Letters So Developing Writers Can Spell Words

and Express Ideas.” Presented at Handwriting in the 21st Century?: An Educational Summit,

Washington, D.C., January 23, 2012.

[5] Mangen, A., and Velay, J. –L. (2010). Digitizing literacy: reflections on the haptics of writing. In Advances in Haptics, edited by M. H. Zadeh. http://www.intechopen.com/books/advances-in-haptics/digitizing-literacy-reflections-on-the-haptics-of-writing

Cold Dead-Fish Education

You have heard the saying, “Give a man a fish and he will eat for a day. Teach him how to fish and he will eat for a lifetime.” Well, when it comes to education, we commonly feed our children cold dead-fish curricula, which they mostly soon forget. The problem is not so much the curriculum as that it is too often delivered at the expense of teaching students how to learn on their own and become lifetime learners. What a lot of them do learn is to shun learning and even hate school enough to drop out.

Fads come and go in education. There was “new math.” Then it was the self-esteem movement. There is the recent heavy emphasis on “hands-on” learning. Now the whole educational enterprise is obsessed with high-stakes testing.

None of these things are bad in themselves. It is just that they disturb educational balance and emphasize teaching students WHAT to learn as opposed to WANT to learn and HOW to learn.

The body politic stills insists we need to throw more money at education and that will fix things. Numerous studies show a lack of correlation between per pupil funding and educational achievement. The school district that spends the most, Washington, D.C., has the poorest educational achievement. Politicians and educators want more money. These are the same folks who think the cure for the federal deficit is to incur more debt so we can “stimulate” the economy. They don’t see the structural problems that are the real causes of economic stagnation. Likewise, they don’t see the real causes of educational stagnation.

Consider this: in terms of inflation adjusted dollars for education, there has been a drastic increase in spending on education in recent years, with very little evident benefit.  As for spending on education, see chart below.

But I recently had an experience suggesting that teachers in the trenches do “get it.” I gave a presentation on Feb. 28 at the Texas Middle School Teachers Association meeting. My session was in a time slot that competed with eight other presentations, yet every chair in my room was taken, while the other sessions had relatively few attendees. It’s not that I am a celebrity. These teachers didn’t know who I am. But they did relate to my topic, “Teach Students How to Remember What You Teach.”[1] I gave the same talk again an hour later and expected few to attend because I assumed that most teachers who were interested in this topic attended the first session. But in the second session, also competing against eight others, the room was again filled and teachers were bringing in chairs from other rooms.

Experienced teachers know that our schools neglect cognitive development. That’s psychology talk for teaching kids how to learn, remember, and think. I have been teaching first-semester college freshmen the last couple of years, and it is apparent that these students have a conspicuous lack of cognitive development, even though my university is highly selective in its admissions. Most of the freshmen lack strategy and tactics for learning and memory. Analytical and creative thinking are typically superficial.

I am doing what I can to help students learn how to learn and remember. Until my recent experience, I doubted that educational policy makers were interested. Maybe now there’s hope.

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[1] I am available for speaking engagements or consultation on this topic. You can email me at billATSIGNthankyoubrainDOTcom.

Announcing a Neuro-education Journal

I began beating the drums for applying neuroscience to educational practice in a 9/28/11 blog post (see archives). Now I am delighted to announce that Elsevier publishers has started a new scholarly journal, Trends in Neuroscience Education. The title is a little misleading because it implies that articles will focus on teaching of neuroscience. On the contrary, all seven articles in the first issue dealt with applying neuroscience information to the practice of teaching and learning.

Two of the first issue articles deal with movement feedback and its affect on cognitive development. These have particular relevance to the teaching of handwriting. The present emphasis on keyboarding and the elimination of penmanship in the curriculum are apparently educationally unwise. This is particularly destructive in schools that are dropping cursive altogether. I will blog about these findings soon.

For now, reader should know that this neuro-education movement is well under way, that I will follow and report on it, and that youngsters will surely benefit. For some time now, I have been contributing to this field by informing teachers about this subject. Today, I am presenting at the Texas Middle School Association teachers' meeting on the subject "Teach Students How to Remember What You Teach." For those who would like me to do school visits and share what I know with students and teachers, check out the possibilities on my education consultant page and get my contact information from the home page of WRKlemm.com.

I assume you all know about my two memory books, one of which is an e-book for students. If you really want a more in-depth yet accessible understanding, I urge you to check out my new e-book, Core Ideas in Neuroscience.

Is Lack of Sleep Causing Your Brain to Shrivel?

Snore a lot? Get up frequently at night to urinate? Wake up at 2 A.M. with bright ideas or worries? All these disruptions of sleep are common and more so as we get older. Does it matter? Well, of course such awakenings disrupt our sleep, and maybe it is just inconvenient. But disrupted sleep not only is more likely with age, it may promote deterioration in mental functioning. A recent study compared the effects of sleeping behavior in young adults and seniors. The study involved assessing the memory after sleeping of 18 young adults in their 20s and 15 older adults in their 70s. The subjects were tested on 120 word sets before they went to bed, and an EEG machine monitored their brain activity while they slept. Upon awakening, they were tested once again on the word pairs, but this time they took the tests while undergoing functional  magnetic resonance imaging (fMRI) scans.

The quality of deep sleep among the older adults was 75 percent lower than the younger ones, and their memory was significantly worse the next day−55 percent worse. The scans suggested deterioration of the frontal lobe. Shrunken brains can occur from aging and shrunken brains impair thinking and memory. But is it possible we have the cause and the effect backwards. Maybe what happens in the environment, such as impaired sleeping, causes both the shrunken brain and the impaired memory. Or in other words, what causes older brains to shrink?

Scientists consider a decrease of about 2% shrinkage every 10 years as normal. That may not be normal, just what most people experience because they are not taking care of their brains. There is abundant research that shows that exercises for both the brain and body help to reduce brain atrophy.

Of course, anything that damages neurons can reduce the number of their tree-like processes and the density of their contact points with other neurons. The list of such causes is long, including: alcohol abuse, brain inflammation, certain infections, concussion, impaired blood supply, lack of intellectual stimulus, vitamin B12 deficiency. It now appears that we should add fragmented sleep to the list.

Common natural causes of fragmented sleep in older humans are alcohol abuse and sleep apnea. Also, in males, enlarged prostate causes a need for frequent urination. As I have explained in my learning and memory blog posts (thankyoubrain.blogspot.com), learning events during the day are consolidated into lasting form during the sleep at night of the same day. We don’t know exactly how sleep helps, but obviously, you have far fewer mental distractions during sleep — unless, of course you keep waking up.

Alzheimer’s Disease also causes fragmented sleep. So, it is no surprise that the brain degeneration by the disease would cause memory problems. But maybe, just maybe, it is the fragmented sleep that accelerates onset of Alzheimer’s disease. Now, this seemingly ridiculous possibility has to be taken seriously in light of new research showing that sleep-disordered breathing, as in sleep apnea, seems to increase the risk of mental decline and even dementia in older women.

Disrupted sleep may also accelerate normal aging. This is certainly true when the cause is sleep apnea, which raises blood pressure and increases the cardiovascular damage that high blood pressure causes. Blood clotting is promoted, increasing the likelihood of strokes. Obesity and diabetes are often associated with sleep apnea, and it seems that sleep apnea not only results from obesity but can promote obesity and the diabetes that often accompanies obesity. Diabetes is toxic for nerve terminals. Similar neuropathy may also be occurring in their brain. Sleep apnea causes daytime sleepiness, and that it turn reduces attentiveness and mental activity, which when sustained over many years reduces the mental stimulus and promotes atrophy of neuronal processes.

Obviously, blood oxygen drops during sleep apnea. Normally, blood is 94% to 98% saturated with oxygen. But not breathing for 30 seconds or more during sleep causes oxygen level to drop to 80% or less. Any level below 90% oxygen level is dangerous, especially to the brain which demands nearly 20% of all the body’s oxygen supply. The adult brain can only survive about four minutes once oxygen is completely cut off.

So it is entirely possible that the slipping memory we see in so many elderly is a warning sign of something much more serious. But by the time the memory deficits show up, much of the damage has already been done. Prevention is the best hope.

Source:

Mander, B. A., Rao, V.,  Brandon, B. L., Saletin, J. M.,  et al. (2013). Prefrontal atrophy, disrupted NREM slow waves and impaired hippocampal-dependent memory in aging. Nature Neuroscience  doi:10.1038/nn.3324 

http://www.livestrong.com/article/161959-what-are-the-causes-of-brain-atrophy/

Yaffe, K., Laffan, A. M., Harrison, S. L. et al. (2011). Sleep-disordered breathing, hyupoxia, and risk of mild cognitive impairment and dementia in older women. JAMA. 306 (6), 613-619. doi:10.1001/jama.2011.1115

For those who want to learn more about the brain, Dr. Klemm has just released the second edition of his e-book, “Core Ideas in Neuroscience.” See http://thankyoubrain.com/neurobook/index.htm