Memory consolidation

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

http://brainconnection.positscience.com/the-day-his-world-stood-still/

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."

Source: thebrain.mcgill.ca

    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 harvard.edu 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.