How does it work and why should it matter?

• Memory: How Does it Work?
• Short- vs Long-term Memory Loss
• Is it Dementia?

Our actions, our thoughts, our feelings, and our choices are all informed by our memory, which is continuously being altered by all that we learn and experience over a lifetime. Memory loss, therefore, can potentially affect us in more ways than we have anticipated.

To better understand memory loss and have a clearer picture of what to expect from it, you may find it helpful to review some of what we know about the brain.

The human brain is made of about 86 billion cells called neurons, connected to one another in an intricate web. The connection point between cells is called synapse, and its function is to form pathways for information to travel from one cell to the next, or neurotransmission. Each brain cell can be connected to others by 10 to 15 thousand synapses.

While we are born with all 86 billion brain cells, they are not well connected to each other at birth. As an infant grows, so do the number of connections between neurons. At birth a baby has 50 trillion synapses. In the first three months of life, the synapses multiply more than 20 times. By the first year, the brain will have 1,000 trillion synapses, which is the same as in an adult brain.

The brain, this complex system of neurotransmitters, is an information processing machine. It has the capability of storing and sorting immense amounts of information. It is estimated that the human brain has memory capacity of up to 1,000 terabytes—or the equivalent of 100 times the content size of the entire U.S. Library of Congress!

However, as you may have observed, the range of memory capacity can vary widely from one person to the next. This is because numerous factors interfere with brain function and capacity. Basically, the better and stronger the synapses, the better the brain will function. Good synapses depend highly on two main factors: the health of the brain cell and the amount of information it receives.

Blood cells travel through blood vessels to transport nutrients and oxygen to brain cells. For each one of our 100 billion neurons there is a dedicated blood vessel delivering nutrients. The quality of these nutrients and the efficacy of the blood delivery system (the vascular system) are essential for brain health. Any interruption in this process can be lethal to the neurons. For each brain cell that is lost, thousands of synapses are interrupted; a brain cell deprived of oxygen will die within just 5 minutes. And the brain needs a lot of oxygen and nutrients: 20% of everything you eat and everything you drink, and all the air you breathe is used to sustain your brain! Considering that the brain size is only 2% of a human body, it consumes an amazing amount of energy. Keeping the brain well supplied with quality nutrients is, therefore, essential for brain health and function. Thus, the brain’s ability to process information is highly dependent on quality nutrients and the health of the vascular system.

The other major factor for brain function is exposure to information. Neuron connections are not frozen in a fixed network: New synapses are continuously formed, and new information pathways are created daily. Brain cells are constantly evolving, reshaping themselves, and physically extending new branches (dendrites) in a continual effort to form new connections with one another. The brain cells’ ability to form new connections and reshape information pathways is called neuroplasticity. This unique ability to change shape allows for better information processing. In other words: Your brain is always changing. It is changing right now as you read this page. The more you read, the more information the brain collects, the more numerous the synapses, and the stronger they will be; and the better the brain will function overall.

New synapses are formed when the brain is exposed to the new information that is collected through our senses. Everything we see, hear, taste, smell, and touch is used to inform the brain. From early childhood, the brain collects information that is then used to create synapses and transform the very pathways used for its processing. New information is processed in light of information that was previously learned, and our brains are constantly evolving. Considering that no two people are exposed to the same information in the same way, no two brains are alike.

Our uniqueness and individuality thus reflect the uniqueness of the development of each of our brains. As a result of exposure to information and the ability of the brain to process it, each brain will create its own pathways and synapses. This ongoing brain activity may partially explain why two people can look at the same facts yet draw dramatically different conclusions. The facts may very well be the same, but the brain pathways processing that information are uniquely different.

Scientists are still a long way from uncovering all the complexities of the human brain. It was not long ago, in 2005, that it was first discovered that the brain also has a highly efficient self-cleaning system that operates independently from other systems in the body. This surprising discovery reminds us that there is still much to learn about the human brain, and ourselves.

Memory: How does it work?

When we talk about memory we are referring to the ability of the brain to encode, store, and retrieve information.

Encoding

Much like data in a computer, information received in the brain through the senses is transformed into a recordable format through a process known as encoding that occurs in the synapses. Encoding uses an elegant system of proteins that either get silenced or activated to record the information. As encoding happens, the very shape of the brain cells change to accommodate the transformation in the neuro connections.

In information processing, the combination of encoding and storage is known as memory consolidation.

Storage

Once encoded, the information must be stored for later use. However, the brain must filter the information received and store it appropriately into categories: ultra-short term, short-term, or long-term memory. The selected category depends on the kind of information received and on how much importance the brain places on the need to recall that information in the future.

Ultra short-term memory contains information that is discarded after just a few seconds. That is the case in sensory memory, in which impressions that are captured through our senses are noted only momentarily and are never to be retrieved again. For example: You look at something for just a second and remember what it looked like, or smell a fragrance that vanishes soon after. Sensory memory is also known as working memory, for it contains the information that the brain uses for operating in the present, such as remembering what a speaker has said long enough to take notes. The brain is constantly bombarded by such information and, if it is not relevant to other memories, the brain will discard it. If the information is considered important, it may be elevated into short-term memory storage.

Short-term memory contains the kind of information your brain considers important to retain temporarily, but it will be discarded a few hours or days later. This may include scenes from a movie or an anecdote heard from a friend. It also includes working memory, or information we need to accomplish a task, such as the instructions to assemble a new piece of furniture. After the task is completed, the information is no longer needed.

Many times, we notice that our ability to retain these memories depends on how much importance we attribute to them. The more important the information, the longer we tend to retain it. The brain judges the level of importance of a piece of information by evaluating it in relation to previously acquired information, resulting from earlier memories. Distinguishing what information to keep and for how long is an essential brain activity for memory retention. The hippocampus is the part of the brain that is primarily responsible for this distinction.

Long-term memory contains previously short-term information that the brain considers relevant enough to upgrade into long-term storage and be kept for years, decades, and in some cases, for life. Those are our milestones, experiences that build our personality and our awareness of the world around us. They may also be memories to which we have attached great emotional value. Examples include giving birth, breaking a leg in an accident as a child, a trip overseas, or driving a car for the first time. These memories are stored in fragments spread throughout the outer layers of the brain (cerebral cortex) and they can be accessed as needed. The more often a memory is accessed the stronger it becomes and the longer it is retained.

Long-term memory also includes procedural memory. With enough practice and repetition, information can be forced into long-term storage, becoming what we consider a skill or muscle memory. These include many functional actions we tend to take for granted, such as those that involve the use of objects or the body: tying shoelaces, playing the piano, or riding a bike. It also includes learned routines such as operating a vehicle, playing a card game, or using a computer. We can train the brain to remember sequences and how to do things, storing memories for long-term use and strengthening synapses with practice.

Retrieval

After encoding and storing information, the final step in memory processing consists in retrieving information as needed. The retrieval process allows stored memories to be consulted when assessing, analyzing, and processing any new information. For example, when encountering a large, black, furry creature on all fours while hiking through the woods, it is by retrieving previous memories that your brain is able to identify it as a bear, analyze it as a potential danger, and decide you should run for your life! And this all happens in a fraction of a second!

Memory retrieval is essential to everything we do and every decision we make, virtually affecting every aspect of our lives. We are continuously informed by our memories. From remembering where your car is parked, to deciding what to wear, or when and how to pay your bills: Your brain is constantly retrieving memories in order to decide what to do next.

Problems in memory retrieval, then, is one explanation of why we forget. People experiencing memory loss often find that, although their memories are intact and properly stored, the brain may experience difficulty in retrieving them.

In such cases, memory-retrieval training can be very helpful. In the same way that we can sear information into long-term memory with the practice of cognitive exercises, we can also train the brain to improve memory retrieval.

There are different types of memory retrieval:

• Recognition: Ability to identify previously learned information. For example, identifying people you have already met in a group.
• Recall: Ability to access the information without using cues. For example, when recognizing a person you have already met, remembering her name.
• Recollection: Ability to reconstruct memory, as in reassembling fragments of memories or learned events into logical narratives. For example, telling your grandchildren about your service during the war, which involves remembering and restructuring various bits of information into a sequential, articulate narrative.
• Relearning: Ability to relearn information that has been previously learned, which further strengthens synapses. This ability can be used in brain-training exercises for the purpose of improving memory, long term storage, and retrieval.

As you can see, memory is not static. It is an ever-changing process in which the brain gathers, categorizes, discards, stores, analyzes, and utilizes multiple kinds of information. While memory is changing, evolving, and pruning itself, the brain itself changes physically, with the growth of new dendrites required to create new synapses.

The good news is that synapses, the connections between brain cells that allow for the processing of all this information, can be strengthened by training exercises. Healthier synapses will result in better memory.

Short- vs long-term memory loss

No one complains of ultra-short term memory problems. This kind of memory is actually supposed to disappear within moments. Most people diagnosed with memory loss complain about short-term memory loss, but not long-term memory loss. In fact, most people notice that their long-term memory is excellent!

Long-term memories are fragmented and stored in the outer layers of the brain, where they are best protected from the brain’s natural aging process. These memories are sedimented and supported by strong synapses. Long-term memories may have been accessed many times over the course of a lifetime, and with every time that information is accessed its memory becomes sturdier. The more often a memory is used, the stronger it is retained. Therefore it is relatively difficult to forget a long-term memory; it may take a catastrophic brain event for that to happen.

Difficulties in retaining short-term memories, however, are common, and a majority of people with memory loss have this problem. Although these kinds of memories are by definition tagged to be discarded soon—sometimes in mere hours or days—the brain may experience problems in any one of the necessary steps for retaining the information for its intended duration.

In some cases the brain may present problems in the memory-consolidation stage and it is unable to distinguish new information from sensory information and, consequently, may quickly discard all new information as such. Alternatively, the brain might misplace or misfile the information, making it difficult to retrieve. Or the brain might experience problems in the retrieval of new memories, regardless of how well they are stored. A thorough neuropsychological examination can help pinpoint the exact nature of the failing steps for those suffering from memory loss. This information can be very useful in devising effective cognitive therapies as well as memory enhancing strategies.

Test Your Own Memory

The University of Ohio has created the Self-Administered Gerocognitive Exam (SAGE), which can be used to detect early signs of cognitive impairment. It tests your short term memory abilities and helps physicians to evaluate how well your brain is working. You can download the exam and use it to test you own memory at:
https://wexnermedical.osu.edu/brain-spine-neuro/memory-disorders/sage

Short-term memory loss can be extremely frustrating. We use short term memory for almost everything we do and we depend on it to do even the most mundane of tasks. We need this kind of memory to:

• Keep track of common objects
• Use the name of a person we just met
• Remember something we just read or heard
• Know why we walked into a room
• Follow instructions and directions
• Schedule and show up on time for appointments
• Follow current events.

Short-term memory loss may not impede the completion of some of our larger projects, but it does hinder our ability to complete some of the necessary small steps involved in the task. It forces us to utilize more time and organization to do things that may have been done quickly and effortlessly in the past. It increases our margins of errors. It is annoying to us.

Thus, it is not uncommon for those affected with memory loss to experience high levels of irritation, anger, and even anxiety. If you have short-term memory loss and have experienced some of those feelings, you are having a very human reaction to a very frustrating situation. Understanding the nature of your memory loss and learning strategies to minimize its effects may help mitigate these feelings.

Is it dementia?

One of the main concerns of those living with memory loss is distinguishing it from dementia. Memory loss is a condition that most people will experience at some point in their lives and with which we all must learn how to live. Dementia is a more pervasive condition; it implies an interference in the ability to conduct our activities as usual.

People affected with memory loss may be diagnosed with Mild Cognitive Impairment (MCI). Although memory loss can increase with time, not everyone with MCI will experience a worsening of the symptoms. Many learn how to manage symptoms and adopt strategies to minimize the risk of progression. Life goes on as planned.

In some cases, however, memory loss does become more severe. This progression is generally a slow process that may take many years, and can be mitigated by the adoption of memory-supportive strategies. The more effective and disciplined MCI patients are in adopting such strategies, the longer they may be able to avoid a progression to dementia.

To be considered dementia, memory loss must be accompanied by other cognitive deficits, and the symptoms must be severe enough to interfere with the ability to conduct daily activities of life.

Dementia is a very relative diagnosis. Fundamentally, if you are able to continue your lifestyle despite memory loss, you don’t have dementia. You may use calendars, reminders, post-it notes, labels, calls from friends, strings on fingers— regardless of the memory aids you may use—if you are able to accomplish your tasks and goals (even if it takes a little longer and you have a few trials and errors), you do not have dementia, you have MCI.

The fundamental difference between MCI and dementia, is that those with dementia are unable to successfully accomplish their goals without outside assistance. If your symptoms require reliance on a loved one or a friend to keep you safe and on track, and you need help accomplishing mundane tasks, you do have dementia.

In practical terms, however, regardless of the diagnosis you receive—memory loss, MCI, or dementia—they all require adoption of the same strategies for retaining and retrieving memory and for stimulating brain functioning. It will be equally important for you to care for your brain health, strengthen your synapses, learn cognitive enhancing strategies, and practice appropriate memory exercises.

These are your best weapons against the worsening of memory loss, MCI, and dementia. The name attributed to your condition is not nearly as important as adapting your lifestyle to keep it from progressing. Medication can help you only so far. Your determination in keeping your brain healthy is what will carry you through and be your greatest ally in the fight against dementia.

Do not let the frustration that comes with memory loss discourage you. There is much you can do to live well with memory loss, delay the onset of dementia, and establish a safer future for you and the ones you love. You can live a fulfilling life with memory loss and you can live a fulfilling life with dementia. It starts with you, your self-awareness, your self-discipline, your courage to do what it takes to care for yourself and fight cognitive impairment head on.

You will also find that most of your friends and loved ones are rooting for you and will be by your side throughout this journey. Let them be with you and for you, and accept help from those who can assist you. You don’t have to travel this road alone.