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WILL YOU REMEMBER THIS BLOG? HOW MEMORY WORKS + 5 TIPS FOR BETTER RECALL

Mya Care Guest Blogger 19 Oct 2020
WILL YOU REMEMBER THIS BLOG? HOW MEMORY WORKS + 5 TIPS FOR BETTER RECALL

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Why is it that sometimes a memory from the distant past is recalled clear as day and yet something that happened 10 minutes ago may be easily forgotten? What decides for us which memories gain preference and in so doing, how our basic personality structures are designed?

Memory and the collective information we have stored inside of us plays a large role in defining who we are and how we will act in the future. Without memory, we would likely have the personality of a stressed-out goldfish, forgetting everything prior to the last 10 seconds and having no data off of which to build our sense of self.

What is it about memory that has this effect over us and how does it work? For a long time, memory has remained one of the greatest mysteries in science. Researchers still battle to give a precise answer to these questions, in spite of how there is more than 100 years of scientific exploration into the subject.

In this review, the latest findings regarding memory will be highlighted. Included in the discussion below are types of memory, factors that influence our ability to recall information (good and bad), and tips for how you can improve recall and learning.

What is Memory?

There are many interpretations of the physical neuro-machinery and mechanisms involved in memory storage and remembrance. [1]

Psychology has dissected the lived experience of remembering an event, breaking it down into a few types of memory and recall. On the other hand, neurobiology has taken a deep look into our bio-machinery and attempted to pinpoint the precise cellular processes involved. Nevertheless, no true consensus has been reached amongst experts thus far and there is still much to be explored.[2]

It is clear that our state of arousal and emotional state of being contribute to how well we retain information and how long that information is stored in the form of a memory.

The information a memory constitutes of is sensory. On a biological level, all the sensory information our bodies take in from the environment comprises of the following:

  • Sensory nerve impulses
  • Neurotransmitter chemicals
  • Hormones (a.k.a. neuro-chemical transporters)

Through the continuously cycling of the above components in response to environmental stimuli, our brains are able to make sense of the world around us.

The neurons in the brain “wire” to form circuits of information between different brain compartments. These circuits are essentially neuro-chemical patterns that become reinforced over time, increasingly more primed to chemically express themselves in response to matching stimuli. These circuits serve as the basis of our long-term memory library and the information that we know, both consciously and subconsciously.

In this way, when you feel good, you may find a lot of good memories rising to the surface of your conscious mind – an ode to the day you stored them there and a mirror of the chemical state of being you are embodying in the present moment. The same can be said for negative and neutral memories.

The cellular process of sorting, storing and organizing relevant sensory information is known as memory consolidation and is on-going, happening 24/7 in an optimally functioning brain. Any slight disruption in the process tends to lead to forgetfulness while major disruptions could hypothetically give rise to full blown amnesia. [3]

The Neuro-Anatomy of Memory

The amygdala, the nuclear accumbens, the adrenal cortex, the hippocampus and parts of the prefrontal cortex are the main areas of the brain involved in recall and learning[4]. Muscle memory is largely dependent upon the cerebellum and tactile sensory information, having far less to do with the cerebral cortex (the part of the brain required for cognitive function).

Ultimately all areas of the brain can be involved in memory formation. If you reflect upon a memory and start to look at it in a new light, other areas of your brain will be contributing to a further consolidation of that memory, enhancing it for future retrieval. This is the basis for how we have the ability to change what we think and why memory is an intimate part of who we are.

Is there a limit to how much information one can store?

Science would argue that there is, but that limit is not discernable at this point and much remains to be elucidated. As it stands, it’s true that the brain can only hold in so much information and that the limit is unique to the individual.

Freeing Up Mental Storage Space

In spite of the hype about boosting one’s recall ability, a healthy part of consolidation demands neuronal pruning.[5]

If new neurons don’t turnover and old one’s remain only to fire the same patterns on repeat, then we do not change or grow as people. Sometimes a lack of dendritic pruning can cause poor memory recall outside of the already existent set of memories a person has. In the most extreme cases, such as in patients with Alzheimer’s Disease, the neurons tangle up into little messes and battle to turnover, causing gaps in synapse functions and chemical transport as well as creating rigid, limited neural pathways and restricting memory consolidation and retrieval.

3 Main Types of Memory

Memory is often divided up into three main types: sensory memory, short-term memory and long-term memory. There are also several sub-types of memory that fall under the below main categories.[6] [7]

1. Sensory Memory

Sensory memory is the first and most basic form of short-term memory, in that it pertains to all the sensory information one takes in during the day. It essentially a sensory photograph of your experience in a moment, capturing everything from the sound of your breathing to the light your brain is decoding in order to render what you see.

 All of our memories began as a sensory memory before proceeding to become short term memories, and eventually long term ones, if persistent enough. Much of our sensory memory is generally not consolidated by the brain post the event for future remembrance.

For example, let’s say you are cooking a meal. All the little sensory details in that moment constitute sensory memory, such as the feeling of your feet on the ground, the smell of what you are cooking or the random sound you didn’t really pay attention to in the distance. These details are often forgotten beyond their practical value in the moment, unless there is some relative importance or emotional input attached to them.

One may have difficulty recalling some of this sensory information (particularly shortly after the event) if the brain’s processing is interrupted with a stressful or exciting stimuli, such as a phone call or a shock of some kind. Sensory details may return to you the next day if the experience they captured marked some kind of important event for you or there was an emotional component. The details that remain will have been consolidated by the brain into short-term memory.

2. Short Term Memory

Why is it that we only remember a fraction of the sensory information we take in on a daily basis? It’s difficult to discern psychologically where the line between sensory memory and short-term memory falls. There is a far more distinguishable gap between short term and long term memory.

Our neurons appear to be adept in discerning which sensory information is important, organizing it in a way that can be accessed for use in the short-term. The majority of short-term memory events are consolidated during deep sleep each night and interrupted sleep can impair the process, preventing a clear recollection.

Eventually, through enough consolidation, short term “events” (neuro-chemical patterns that mimic past patterns of sensory input) are committed to long term memory, indexed according to their relevance.

3. Long Term Memory

The memories we tend to store long-term are those that we are well-practiced at retrieving, as well as those that have a strong emotion linked to them (chemically speaking).

Hormones and neurotransmitters are responsible for making us feel all our emotions and are intimately involved in forging memories on a neurological basis. When a child burns their hand for the first time, the feelings of fear, surprise, and the painful sensation of burning all contribute to the chemical signature of that experience and memory. The brain and all its neurons will consolidate that information into the long-term rather quickly, usually to prevent it from occurring again.

Factors That Influence Memory

Stress hormones, BDNF and cellular energy metabolism (discussed below) are all involved in consolidating memory in neurons and promote learning. [8]

In the brain, the consistent cross-talk between these three factors forms a type of chemical feedback loop that is observed during memory formation. This emergent pattern is now an established cellular pathway known as the Glucocorticoid-BDNF-CREB pathway[9]. Scientists are currently exploring it in order to better understand memory formation, cognition, learning and various mental disorders.

If any part of this pathway is chemically unbalanced or interrupted when one is learning or forming a new memory, the brain will not likely recall the information as accurately.

Below is a brief discussion of the factors that influence the G-BDNF-CREB pathway; hence affecting our ability to remember the past and respond to the future.

The Good

BDNF (Brain-Derived Neurotrophic Factor)

Brain-Derived Neurotrophic Factor is a chemical molecule expressed by neurons that exerts multiple effects in order to carry out normal brain functions, including new nerve cell growth and memory formation. [10]

If BDNF is blocked at any part of the memory consolidation process, that part appears to become hampered. BDNF is very important for memories to make their way from mere sensory stimuli into fully fledged long-term memories.[11]

BDNF is also responsible for optimal cognitive function, keeping calm and retaining a balanced mood throughout the day.

Cellular Energy Balance

The CREB part of the G-BDNF-CREB pathway pertains to cellular energy metabolism and balance. The mitochondria are parts of each cell that deal with energy metabolism and are responsible for regulating this portion of the pathway in neurons.

CREB stands for cAMP response element-binding protein. cAMP is one of many types of mitochondrial energy molecules[12], intimately involved in fat metabolism, neural function and immune system activity.

cAMP forms a ratio with cGMP, another energy molecule, having an inverse relationship. cAMP is required for long-term memory formation, while cGMP is needed for short-term memory formation[13]. Both are required in balance to make the transition from short to long term retention. This ultimately means keeping your brain’s mitochondria happy and healthy.

On this note, when one is not well, does not get enough quality sleep, eats a diet that promotes excessive inflammation or leads a sedentary lifestyle, the above ratio can become distorted in mitochondria and potentially have an effect on memory formation, recall and learning. [14]

The Bad

Excessive Neuro-Excitability (Neurotoxicity)

Excessive neuro-excitability is a fancy way of describing an overactive neuron. Overactive neurons tend to swell or shrink due to heightened chemical activity either in or around the cell. In extreme cases, overactive neurons can burst open or implode, causing the neuron to die-off. [15]

Losing too many neurons or having a deficit of them while trying to remember something naturally results in an interruption in memory consolidation.

Neurotoxins and excitotoxins are chemical agents that induce heightened neuro-excitability and cell death, when concentrations exceed the person’s natural tolerance or safety limit. Examples include mercury (neurotoxin) and the artificial sweetener aspartame (excitotoxin).

Other factors that can induce similar over-activity in the nervous system include:

  • Excessive brain glutamate levels[16]
  • Heightened neuro-inflammation
  • Too high or too low brain glucose levels
  • Gut Dysbiosis
  • Infections
  • Heightened stress levels[17]
  • Alcohol intoxication
  • Trauma
  • Nutritional deficiencies

Lack of Quality Sleep

When we get adequate quality sleep at night, it means our brains have had enough time engaging in each of the phases of the sleep cycle. The first phase, light sleep, does not appear to have a use in this context, other than to get our brains into the second and eventual third phase of sleep.

The third phase of sleep, known as deep sleep or slow wave sleep, is a particularly important phase for memory consolidation and learning. [18]

Some psychologists and neuroscientists hypothesize that dreaming is a part of memory consolidation and that our subconscious minds are attempting to better organize the information we take in on a daily basis. If that is true, the second phase, REM sleep may also play an important role in promoting memory retention. Research has shown that REM is involved in pruning dendrites and “freeing up storage space” in the brain.[19]

We enter the phases of sleep in cycles, typically completing all three within 3-4hour stretches. If one is abruptly awoken during this time, it will affect the quality of sleep and memory consolidation. However, being woken up between these stretches of time does not seem to affect this process and often one can easily fall back to sleep when this occurs.

The Ugly

Stress Chemicals

Stress chemicals belong to a group of hormones known as glucocorticoids and form the final part of the G-BDNF-CREB cognition pathway (see BDNF and energy metabolism above).

What is the Stress Response and Why Do We Need It?

Have you ever been in a conversation where your mind tuned out large portions of what someone said, only keeping the “most important” or “relevant (to you)” information? It could be that you have stress hormones interfering with your ability to collect and remember all the information as opposed to just a section of it.

Stress is a mode the body steps into in order to preserve itself through restricting one’s focus; condensing it down to an immediately dangerous situation and highlighting only the sensory information deemed relevant to survival.

As a result, all energy reserves are drawn toward the situation, preventing their use in parts of the brain that would otherwise facilitate memory, learning, and a clearer understanding. Naturally, an acute stress response lowers our ability to think rationally and heightens our ability to physically react – the components of a typical “fight or flight” response.

In order to remember something accurately, we need to have the hippocampus and a few other brain areas functioning optimally. These tend to be impaired when there are high levels of corticoids present[20], however, an acute stress can also promote long-term memory formation and learning from exposure to danger.

Many will agree that 2020 has been a particularly stressful year for humanity, perhaps highlighting now the need more than ever for us to acknowledge the health risks associated with modern day living and to do something constructive about it!

How Stress Chemically Breeds Both Intelligence and not.

Stress regulation seems to be a substantially under-appreciated part of cultivating intelligence.

Balanced corticoid levels constitute our state of arousal, playing a crucial role in keeping us awake, active and focused throughout the day. The nervous system is particularly sensitive to stress hormones.

Excessive corticoid levels in the brain directly lower the concentrations of BDNF and therefore decrease cognitive function and recall ability.[21] If corticoid levels fall below the amount required to sustain the basic arousal state, one can feel sleepy, battle to focus and have trouble remembering information.

Furthermore, too much cortisol in the brain for a prolonged time provokes a state of neurotoxicity, particularly in the hippocampus. Research has revealed that excess chronic stress is capable of enhancing the negative side of inflammation[22], starving neurons of glucose and glutamate, impairing balanced energy metabolism and shortening their lifespan[23]. Furthermore, stress impairs neurogenesis (the growth of new neurons) in the hippocampus.[24]

Post-Traumatic Stress in Connection to Memory

Certain types of stress chemical patterns can cause overactive memory consolidation, promoting excessive recall and analysis of an event. This is essentially a description of post-traumatic stress. Traumatic events are native to life and our bodies use them to develop a keen sense of caution when navigating danger.

Sometimes the memory associated with a trauma is forgotten, but the chemical pattern remains salient at the cellular level, expressing itself whenever the same emotions or thoughts arise. In this way, someone can react to a person or situation inappropriately without understanding what possessed them to do so!

In those with chronic PTSD, neurons are particularly sensitive to stress and primed abnormally in response to any stimuli that happens to mimic the trauma on a chemical level. While forgetting on a conscious level is not always enough to stop the cycle at the cellular level, science is making lots of progress in finding novel approaches to dealing with PTSD and other memory-related disorders.[25]

  • If you are pre-disposed to inheriting a mental health disorder, it might be of use to know that chronic stress substantially increases the risk for just about all of them!
  • Chronic stress is also associated with the following[26]:
  • Nutritional deficiencies
  • Chronic inflammation
  • Difficulty sleeping
  • Reduced ability to learn new things
  • Excitotoxicty
  • Recovery fatigue (mimics a post-trauma recovery state)

5 Tips for Better Remembrance, Focused Attention and Cognition

Battling to remember everything you just read? The following five tips may help you to optimize your brain function and improve memory recall.

1. Keep Calm

In order to ensure better cognition and recall, the first thing to focus on is stress regulation.

Stress is a natural part of everyday living for all of us, without exception. Those who can regulate their stress levels can adapt to new situations with relative ease and tend to be able to hold more information on average.

Here are a few suggestions that may help one to keep calm and maintain optimal stress levels:

  • Grandma’s Tea. Most tea contains many compounds that can lower blood cortisol levels and help to regulate stress. Green tea, mint, rooibos, chamomile and jasmine are all good options.
  • Breathe. Focused deep breathing has been shown to have a calming effect, stabilizing the heart rate and lowering stress[27], particularly stress induced due to compromised breathing.
  • Sunlight and fresh air. Basking for short amounts of time in sunlight is known to boost BDNF[28] and lower corticoid levels[29]. Spending too long in the sun can result in sunburn, subsequent inflammation and too long exposure to radiation. Genetic resilience and developed tolerances to sunlight differ from person to person.
  • Exercise. Moderate exercise tends to release endorphins and other “feel good” chemicals which can help to improve BDNF and lower stress levels. Exercise in moderation also contributes to improving overall cellular energy production and regulating metabolism, thus further contributing to boosting memory retention.[30]

2. Declutter the mind

Keeping a calm, quiet mind can help the brain to focus on the environment and process more sensory information. The same can be said of a good listener – someone that gives all their attention to the speaker and calmly receives all the sensory information that is being expressed, both verbally and non-verbally.

If one’s mind is cluttered to the point of distraction, it can be difficult to receive new sensory information and remember current events well.

Stressful or emotional events in particular can give rise to persistent overthinking. Any extra thoughts that arise in response to a situation throw additional chemical nerve signals into the process of memory consolidation, particularly thoughts that give rise to strong emotions. As a result, less extra-sensory information is received and more internal information (side thoughts, extra interpretations and emotional inflections) are stored alongside our memories.

If you’re not sure how to declutter your mind or you find it challenging, the following questions may be useful:

  • Where is your point of focus right now?
  • Is that focal point detracting from your ability to take in your current living experience?
  • If so, are you having difficulty focusing on your momentary experience and away from the distraction?
  • If yes, is there anything you can do to break the neuronal feedback loop?

The last question is the most important in this list and starts to delve into changing one’s internal behavior and self-talk.

If your mind is accustomed to firing irrelevant thoughts all the time that detract from learning and recall, then one needs to change the way their neurons are wired. All that is required to do this is sufficient interruption of the thought process (the old behavior), followed by the cultivation of a new thought process (the new behavior) – in this case, a silent thought process that allows you to take in more information and consolidate memory at an optimal efficiency. It may take some time to declutter the mind, particularly if the individual has a well-practiced set of thoughts and feelings that they linger on.

Mindfulness practices have grown in popularity across the globe due to their effectiveness at stilling the mind. Research into meditation and yoga has revealed that they work well to lower stress levels and are great for overall brain health. [31]

Training aside, anyone can practice to still their mind by shifting their attention back to their surroundings in each moment and disengaging from their thought process.

3. Stay Healthy

Staying healthy is important for ensuring all the organs in the body function optimally, including the brain. In particular, getting proper nutrition and ensuring quality sleep are both vital for optimizing memory consolidation and recall.

  • Sleep. Falling asleep before midnight and waking up with the sun compliments our biology by enforcing a healthy circadian rhythm. The circadian rhythm sets the tone for the release of all hormones throughout the day and night, including corticoid release[32] [33], which is why it is vital to ensuring optimal brain function. Sleep itself helps the brain to cleanse and remove toxins that build up throughout the day by draining the cerebral spinal fluid[34]. Furthermore, as explained above, sleep is necessary for short-term memory consolidation.
  • Getting adequate nutrition. The brain does best with large doses of the following nutrients: Omega-3 fats, unsaturated fats, B Vitamins, Vitamin D3, Vitamin K2, Vitamin E, C and A, calcium, zinc, magnesium, selenium, choline, iron and copper. Flavonoids from nutrient-dense foods can further enhance the actions of these nutrients. Food source examples include green tea, dark chocolate, berries, citrus, herbs and spices.[35]
  • Avoiding Inflammatory Exposures. Anything that causes excessive brain inflammation can create a disruption in memory formation and recall. Everyone has a unique immune system, meaning tolerance to foods and environmental exposure to toxins differs from person to person. If you know you are allergic to something or don’t react physically well to any particular stimuli, you ought to avoid it to improve your memory. Examples may include chemical use around the home, exposure to mold or ingesting an allergen.

4. Repetition

Practice makes perfect!

Repeating information and practicing your recall ability naturally helps to strengthen the neural feedback loops your brain needs to do in order to retrieve the information. It has been argued that repeating information either 3 or 7 times has a better result with regard to long-term consolidation. In truth, consistency on a daily basis is the only way forward until the memory is recorded and retrieved with ease.[36]

Considering there are so many factors that could affect your memory in a given moment, the amount of repetition required may differ depending on your stress levels, health and the event to be remembered.

5. Boost that BDNF

  • Sunlight and Vitamin D3. As mentioned above, sunlight lowers cortisol and enhances BDNF. Our bodies are equipped for making Vitamin D3 by converting it from D2 when we enter sunlight. D3 is also required for adequate quality sleep, which further promotes a healthy brain function. Vitamin D3 supplementation has similar effects to sun-basking for those who are deficient and may be a common deficiency for those who spend lots of time indoors and who lead a sedentary lifestyle.
  • Caloric Moderation. Evidence suggests that moderating our calorie intake[37] as well as caloric restriction[38] can improve brain BDNF levels. Caloric restriction is only beneficial when one is consuming adequate nutrition to sustain themselves – the point is not to starve but to promote balanced energy metabolism. Speak first to a healthcare expert or nutritionist before adopting any intensive diet.
  • Learning A New Skill. It has long since been known that children require lots of exposure to sports and other physical activities in order to help them grow and learn new things. Research indicates that it is not so different for adults - learning a new physical skill and developing other areas of the brain can help one to boost BDNF levels.[39]
  • Flavonoids That May Increase Brain BDNF Levels. Flavonoids are chemical components in food that give them their color and flavor. The following may boost BDNF (as shown in rat studies*), either directly or indirectly via lowering chemical stress factors[40]:
    • Hesperidin, nobiletin, and naringenin, found mostly in citrus fruits.
    • Chrysin, found in honey and bee products.
    • Luteolin, found in most fruit and vegetables, but especially in onion family foods, brassicas, carrots, peppers, celery, parsley, apple skins and chrysanthemum flowers.[41]
    • Vitexin, found in passionfruit.diet chol
    • Quercetin, found mainly in quinces, onions, apples, broccoli and green tea.

*More research is required to confirm these findings in humans.

Conclusion

Memory forms a vital part of who we are individually and defines many aspects of our behavior, particularly our thoughts, feelings and reactions. Understanding memory formation and retention can help us to decide who we want to be and make the changes necessary to become that being.

The main factors that influence memory retention are our levels of stress, brain levels of BDNF and cellular energy metabolism. Diet and lifestyle factors play a large role in regulating these factors, and include sleep quality, exercise, exposure to sunlight and consuming adequate nutrition for optimal brain health. Stilling the mind, lowering stress levels, remaining receptive to learning new things and repeating the information we learn are all strategies that can be employed to enhance memory function.

Before implementing any drastic changes in your diet or lifestyle, please consult with a registered healthcare provider about your case. This applies particularly if you are already following a healthcare protocol.

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Source:

  • [1] https://www.cell.com/cell/fulltext/S0092-8674(14)00290-6?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867414002906%3Fshowall%3Dtrue
  • [2] https://pubmed.ncbi.nlm.nih.gov/22220356/
  • [3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4246028/
  • [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3236701/
  • [5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5535798/
  • [6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5491610/
  • [7] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2657600/
  • [8] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4246028/
  • [9] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509234/
  • [10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2821174/
  • [11] https://www.pnas.org/content/105/7/2711
  • [12] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3870303/
  • [13] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4207334/
  • [14] https://www.frontiersin.org/articles/10.3389/fnmol.2015.00046/full
  • [15] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4002277/
  • [16] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4679930/
  • [17] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4422005/
  • [18] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3768102/
  • [19] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5535798/
  • [20] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3059694/
  • [21] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3979509/
  • [22] https://www.karger.com/Article/FullText/367849
  • [23] https://pubmed.ncbi.nlm.nih.gov/1680166/
  • [24] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3059694/
  • [25] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393536/
  • [26] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2568977/
  • [27] https://pubmed.ncbi.nlm.nih.gov/27995346/
  • [28] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3487856/
  • [29] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3686562/
  • [30] https://www.frontiersin.org/articles/10.3389/fpsyg.2015.01890/full
  • [31] https://www.ecronicon.com/ecne/ECNE-12-00694.php
  • [32] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5314421/
  • [33] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6279965/
  • [34] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4651462/
  • [35] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805706/
  • [36] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050388/
  • [37] https://pubmed.ncbi.nlm.nih.gov/19012000/
  • [38] https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1129&context=sbcoa_facpub
  • [39] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6473056/
  • [40] https://www.hindawi.com/journals/omcl/2017/5762172/
  • [41] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2615542/
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