Memory consolidation

Consolidating Memory for Long Term Learning

On Neuroplasticity

Learning changes the brain

On José Martí

"Pensar es servir"

Word and Mind

Every mind is creative

Click here for an overview of this topic mapped on Prezi.

"Learn­ing is crit­i­cal at all ages, not only in the school envi­ron­ment. We have brains pre­cisely in order to be able to learn, to adapt to new envi­ron­ments.

"This is essen­tial through­out life, not just in school. We now know that every brain can change, at any age. There is really no upper limit on learn­ing since the brain neu­rons seem to be capa­ble of grow­ing new con­nec­tions when­ever they are used repeat­edly.

"I think all of us need to develop the capac­ity to self-motivate our­selves. One way to do that is to search for those mean­ing­ful con­tact points and bridges, between what we want to learn and what we already know. When we do so, we are cul­ti­vat­ing our own neu­ronal net­works. We become our own gar­den­ers."

Dr. James Zull, Pro­fes­sor of Biol­ogy and Bio­chem­istry

Sharp Brains, September 6, 2007

What is memory?

Memory is usually described as the process by which the brain encodes, stores, and retrieves information.

Encoding is the process of transforming the information we receive from the outside world through our senses into the electrical and chemical signals that activate our brain cells.

Storing refers to the changes that happen in the brain to keep information over periods of time.

Retrieving is the process of locating information stored in the brain to make it available to us.

Types of memory

When we store information, we are creating a memory. What the information is, and how long we store it, determines what type of memory it is.

Different models or classification systems are used to help us understand different types of memory. Our model provides two major memory classifications - short-term memory and long-term memory.

It subdivides long-term memory into conscious or explicit memory and unconscious or implicit memory.

Conscious, explicit memory subdivides into autobiographical or episodic memory and semantic memory.

Unconscious, implicit memory includes procedural memory and priming.

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Henry Gustav Molaison (1926-2008)

How memory works

"What are memories? How do they form, and why do they seem so real? How could a famous psychology subject named H.M. retain long-term memories of his childhood yet not recall short-term memories, like what he ate for lunch? Neurobiologists and psychologists are discovering the details of how memory works, including pinpointing molecules that can create memories as well as those that can erase memories forever."

NOVA scienceNOW Posted 08.25.09

Neuroscientists often refer to H.M. as the most important patient in the history of brain science. His case study has provided the basis of our understanding of memory.

Watch the video at the link below

Here's another interesting and informative account of Henry Molaison's case study in Posit Science - Brain Connection:

Henry Molaison's case history continues to make waves in neuroscience

The Atlantic published an article by Ed Jong on August 12, 2016.

Jong's article is titled "A Book About Neuroscience’s Most Famous Patient Sparks Controversy"

It's an interview with Luke Dittrich who wrote a book titled, Patient H.M.: A Story of Memory, Madness, and Family Secrets.

Jong writes: "Dittrich is uniquely placed to consider these issues. Scoville [H.M.'s surgeon] was his grandfather. Suzanne Corkin, the scientist who worked with Molaison most extensively after his surgery, was an old friend of his mother's. I spoke to him about the book and the challenges of reporting a story that he was so deeply entwined in."

Jong's article provides insights into ethical issues that are interesting to consider in relation to H.M.'s surgery, and his participation as a subject in scientific research - H.M., whose life and circumstances radically changed what we know about, and how we understand memory.

It's an interesting and informative read.

Learning and memory

Learning and memory are interrelated and may be described in terms of three functions:

(1) acquisition, or the introduction of new information to the brain;

(2) consolidation, or the process of strengthening and stabilizing memory; and

(3) recall, or the ability to retrieve or acess information after it has been stored.

"Memory and learning are so closely connected that people often confuse them with each other. But the specialists who study them consider them two distinct phenomena.

"These specialists define learning as a process that will modify a subsequent behaviour. Memory, on the other hand, is the ability to remember past experiences.

"You learn a new language by studying it, but you then speak it by using your memory to retrieve the words that you have learned.

"Memory is essential to all learning, because it lets you store and retrieve the information that you learn. Memory is basically nothing more than the record left by a learning process.

"Thus, memory depends on learning. But learning also depends on memory, because the knowledge stored in your memory provides the framework to which you link new knowledge, by association. And the more extensive your framework of existing knowledge, the more easily you can link new knowledge to it."


Attention and memory

Attention and memory are co-dependent, because memory has a limited capacity, and attention determines what will be encoded into memory. On the one hand, for conscious memories to be formed, we have to pay attention, because divided attention prevents the encoding of conscious memories. On the other hand, memory from previous experience predicts and guides where we should pay attention.

The nucleus basalis is that part of the brain that helps us to focus our attention and remember what we are experiencing. It is a group of neurons in the lower area of the frontal lobe. During the critical period of early childhood, when learning is effortless, BDNF turns on the nucleus basalis, and keeps it turned on. After the main neuronal connections are in place, the brain releases BDNF in sufficient qualtities to turn off the nucleus basalis and end the critical period of effortless learning. From here on, the brain activates the nucleus basalis only when something new and interesting occurs, or when we make the effort to pay attention.

Emotional engagement is critical. We pay attention to things that interests us and that we can connect to emotionally. The hippocampus, part of our limbic system - i.e., our "emotional brain" - is involved in the task of paying attention and determining what will be encoded into long-term memory.

"We don't pay attention to boring things."

Source: John Medina, Rule #4, Brain Rules

"What we pay attention to is profoundly influenced by memory. Our previous experience predicts where we should pay attention. Culture matters too. Whether in school or in business, these differences can greatly affect how an audience perceives a given presentation.

"We pay attention to things like emotions, threats and sex. Regardless of who you are, the brain pays a great deal of attention to these questions: Can I eat it? Will it eat me? Can I mate with it? Will it mate with me? Have I seen it before?

"The brain is not capable of multi-tasking. We can talk and breathe, but when it comes to higher level tasks, we just can’t do it.

"Driving while talking on a cell phone is like driving drunk. The brain is a sequential processor and large fractions of a second are consumed every time the brain switches tasks. This is why cell-phone talkers are a half-second slower to hit the brakes and get in more wrecks.

"Workplaces and schools actually encourage this type of multi-tasking. Walk into any office and you’ll see people sending e-mail, answering their phones, Instant Messaging, and on MySpace—all at the same time.

"Research shows your error rate goes up 50% and it takes you twice as long to do things.

When you’re always online you’re always distracted. So the always online organization is the always unproductive organization."

The fallacy of multitasking

Multitasking continues to be regarded as a required and prized skill because the idea that the brain can focus on more than one task at a time still prevails among students, employees, and employers in various settings and workplaces. However, modern neuroscience and numerous studies have shown multitasking is a fallacy. Although we can walk, talk, and breathe at the same time, the brain can focus attention on one higher-level task at a time.

When we think we're multitasking, we are in fact task-switching - i.e., interrupting our attention from one task to pay attention to another. Driving while talking on the phone is one example. While "multitasking" may be a requirement of managing our responsibilities at home, on campus, and in the workplace, interruptions and task-switching compromise results and efficiency. Research shows there's a 50% increase in error rate, and it takes twice as long to finish tasks. In the workplace, the result is higher costs, inferior results, and more stress.

To reduce time and improve efficiency, whenever possible, focus on and complete one task at a time. As we often don't have that luxury, manage the interruptions and your time in a way that best allows you to focus effectively on one task before switching to another. Consider tracking the number and degree of distractions and interruptions occurring between tasks. Heightened awareness will contribute to enhanced time management strategies and improved results. A record of interruptions and distractions may also help to inform conversations as well as improve conditions and efficiency in the workplace.

On the roadways, driving while talking - like drinking and driving - yields tragic consequences.

Multisensory integration

We experience the world through sight, sound, taste, smell, and touch. Multisensory integration refers to the way our brain constructs perception by processing sensory stimuli from various senses. It is a way of explaining how different senses - such as sight, sound, touch, smell, taste - interact with one another and alter each other's processing. The "McGurk effect" is one example. Vision affects what we hear. Show a picture of a person saying "ga ga ga." Play an audio saying "ba ba ba." We perceive the person saying "da da da."

Our senses evolved to work together; our brain uses information it receives from all our senses to perceive our world and interpret our experiences. Consequently, learning theories suggest we should stimulate and involve as many of our senses as possible in learning activities because stimulating our senses of touch, taste, smell, hearing, and seeing enhances the learning environment and can have a positive effect on learning. For example, researchers suggest subjects who enjoyed popcorn or the smell of popcorn while viewing a movie, remembered 10% to 50% more details when tested on the details of the movie while the smell of popcorn is introduced into the air.

Similarly, we learn and perform better when we function in multisensory environments that involve as many of our senses as possible, and require us to engage in a variety of learning activities.

Sleep and the consolidation of memory

Humans generally spend one-third of our lives asleep. How long we sleep and how well we sleep affects learning and memory. Sleep-deprivation negatively affects our ability to focus and pay attention, and consequently, our ability to learn. Neurons in sleep-deprived brains cannot effectively function for memory, the result being that we cannot or have difficulty retrieving learned information. Sleep deprivation also negatively affects mood, motivation, judgment, and perception. Our ability to make sound decisions, perceive and assess situations, plan and act accordingly, becomes impaired. Tired brains and tired bodies are not synchronized; in addition to cognitive impairment and reduced performance level, accidents and injuries may occur.

Sleep also plays an critical role in memory consolidation. Our brain is very active when we're asleep, and research suggests sleep is important both before and after learning a new task. Sleep helps consolidate memories, making them stronger, so that we can retrieve them later. Sleep also reorganizes and restructures memories. Scientists have measured brain activity during sleep and discovered that the areas of the brain involved with emotion and memory consolidation are active.

Studies suggest that REM (rapid-eye-movement) sleep - a stage of sleep in which dreaming occurs most frequently - appears to be involved in the processing of conscious/declarative memory when information is complex and has emotional content. REM sleep appears to also play a critical role in procedural memory - i.e., remembering how to do something. According to a source, "REM sleep seems to plays a critical role in the consolidation of procedural memory. Other aspects of sleep also play a role: motor learning seems to depend on the amount of lighter stages of sleep, while certain types of visual learning seem to depend on the amount and timing of both deep, slow-wave sleep (SWS) and REM sleep." These are areas of continuing research.

Russell Foster provides a clear and informative presentation on sleep in this TED Talk.

The learning experiment - the tortoise and the hare effect

Reported by Norman Doidge in The Brain that Changes Itself

Alvaro Pascual-Leone designed an experiment which confirmed that learning a new skill changes the brain.. He used TMS (transcranial magnetic stimulation) to map the brains of blind subjects learning to read Braille. They studied Braille for a year, five days a week - two hours in class followed by one hour of homework daily. Braille readers read by learning to scan the arrangement of raised dots with their index finger, which is a motor activity.

His findings showed learning Braille results in changes in a person's motor cortex. The map of the Braille-reading finger becomes larger and increased in size according to an increase in the number of words that could be read per minute. His findings also showed the pattern of brain changes over the duration of the learning process.

Using TMS to map the brains of research subjects on Fridays, after the week's training, and on Mondays, after they had rested, he found consistent differences in Friday and Monday maps. For six months, Friday maps showed an increase in size, but Monday maps returned to baseline size. Friday maps during the first six months expanded more dramatically than Friday maps after six months, but they were consistently larger than Monday maps.

Monday maps returned to baseline size over the first six months, then they began to increase slowly and plateaued at ten months. Monday maps changed less dramatically than Friday maps, but Monday maps were more stable and correlated better with the Braille-reading skills research subjects were acquiring.

Ten months of training were followed by a two-month break. When research subjects returned and their brains were mapped, their brain maps were the same as their Monday maps two months earlier.

For Pascual-Leone, Friday and Monday maps suggest different plastic changes. Rapid, dramatic Friday changes suggest the strengthening of existing neuronal connections - synapses and neuronal pathways. Slower but more stable Monday maps suggest new neuronal connections.

In the Aesop fable, the hare is faster, but the tortoise wins the race. This "tortoise-and-hare effect" helps to explain the learning process. Cramming strengthens existing synaptic connections and may work as a short-term strategy. It produces "the Friday effect." Learning, i.e., encoding into and retrieving long-term memory, requires repetition, practice, and steady work over an extended period of time to produce "the Monday effect."

Recommended Resources

Marvin M Chun and Nicholas B Turke-Brown - Interactions between attention and memory

The Dana Foundation, Learning and Memory

Russell Foster - TED Talk - Why do we sleep? The Neuroscience of Sleep

The Guardian, How your brain likes to be treated at revision time on Heathy Sleep

Michael Merzenich - TED Talk - Growing Evidence of Brain Plasticity

MIT News, How attention helps you remember

Posit Science, Memory

Sharp Brains, Brain Plasticity: How learning changes your brain

TeachThought, The Neurological Benefits of Practice

Ed Yong, A Book About Neuroscience's Most Famous Patient Sparks Controversy