How Memories Are Formed And Retrieved By The Brain

How Memories Are Formed And Retrieved By The Brain
Forming and recalling memories is a complex system of synchronisation and desynchronisation in different parts the brain. decade3s- anatomy online/ Shutterstock

Try to remember that last dinner you went out for. Perhaps you can remember the taste of that delicious pasta, the sounds of the jazz pianist in the corner, or that boisterous laugh from the portly gentleman three tables over. What you probably can’t remember is putting any effort into remembering any of these little details.

Somehow, your brain has rapidly processed the experience and turned it into a robust, long-term memory without any serious effort from yourself. And, as you reflect on that meal today, your brain has generated a high-definition movie of the meal from memory, for your mental viewing pleasure, in a matter of seconds.

Undoubtedly, our ability to create and retrieve long-term memories is a fundamental part of the human experience – but we still have lots to learn about the process. For instance, we lack a clear understanding of how different brain regions interact in order to form and retrieve memories. But our recent study sheds new light on this phenomenon by showing how neural activity in two distinct brain regions interact during memory retrieval.

The hippocampus, a structure located deep within the brain, has long been seen as a hub for memory. The hippocampus helps “glue” parts of the memory together (the “where” with the “when”) by ensuring that neurons fire together. This is often referred to as “neural synchronisation”. When the neurons that code for the “where” synchronise with the neurons that code for the “when”, these details become associated through a phenomenon known as “Hebbian learning”.


 Get The Latest By Email

Weekly Magazine Daily Inspiration

But the hippocampus is simply too small to store every little detail of a memory. This has lead researchers to theorise that the hippocampus calls upon the neocortex – a region which processes complex sensory details such as sound and sight – to help fill in the details of a memory.

The neocortex does this by doing the exact opposite of what the hippocampus does – it ensures that neurons do not fire together. This is often referred to as “neural desynchronisation”. Imagine asking an audience of 100 people for their names. If they synchronise their response (that is, they all scream out at the same time), you’re probably not going to understand anything. But if they desynchronise their response (that is, they take turns speaking their names), you’re probably going to gather a lot more information from them. The same is true for neocortical neurons – if they synchronise, they struggle to get their message across, but if they desynchronise, the information comes across easily.

Our research found that the hippocampus and neocortex do in fact work together when recalling a memory. This happens when the hippocampus synchronises its activity to glue parts of the memory together, and later help to recall the memory. Meanwhile, the neocortex desynchronises its activity to help process information about the event and later help process information about the memory.

Of cats and bicycles

We tested 12 epilepsy patients between 24 and 53 years of age. All had electrodes place directly within the brain tissue of their hippocampus and neocortex as part of the treatment for their epilepsy. During the experiment, patients learned associations between different stimuli (such as words, sounds and videos), and later recalled these associations. For example, a patient may be shown the word “cat” followed by a video of a bike cycling down a street.

The patient would then try and create a vivid link between the two (perhaps the cat riding the bike) to help them remember the association between the two items. Later, they would be presented with one of the items and asked to recall the other. The researchers then examined how the hippocampus interacted with the neocortex when the patients were learning and recalling these associations.

During learning, neural activity in the neocortex desynchronised and then, around 150 milliseconds later, neural activity in the hippocampus synchronised. Seemingly, information about the sensory details of the stimuli was first being processed by the neocortex, before being passed to the hippocampus to be glued together.

How Memories Are Formed And Retrieved By The Brain
We found that the hippocampus and neocortex work closely together when forming and retrieving memories. Orawan Pattarawimonchai/ Shutterstock

Fascinatingly, this pattern reversed during retrieval – neural activity in the hippocampus first synchronised and then, around 250 milliseconds later, neural activity in the neocortex desynchronised. This time, it appeared that the hippocampus first recalled a gist of the memory and then began to ask the neocortex for the specifics.

Our findings support a recent theory which suggests that a desynchronised neocortex and synchronised hippocampus need to interact to form and recall memories.

While brain stimulation has become a promising method for boosting our cognitive facilities, it has proved difficult to stimulate the hippocampus to improve long-term memory. The key problem has been that the hippocampus is located deep within the brain and is difficult to reach with brain stimulation that is applied from the scalp. But the findings from this study present a new possibility. By stimulating the regions in the neocortex that communicate with the hippocampus, perhaps the hippocampus can be indirectly pushed to create new memories or recall old ones.

Understanding more about the way the hippocampus and neocortex work together when forming and recalling memories could be important for further developing new technologies that could help improve memory for those suffering from cognitive impairments such as dementia, as well as boosting memory in the population at large.The Conversation

About the Authors

Benjamin J. Griffiths, Doctoral Researcher, University of Birmingham and Simon Hanslmayr, , University of Birmingham

This article is republished from The Conversation under a Creative Commons license. Read the original article.

books_behavior

Monday, 24 July 2023 16:37

Uterine fibroids, or leiomyomas, are benign tumors commonly occurring in the uterus. They affect many women, particularly African Americans, and can lead to clinical symptoms such as abnormal...

Friday, 21 July 2023 15:37

During uncomfortably hot weather, people seek ways to cool down their homes. Air conditioners often become the default solution when temperatures rise as they provide fast and effective relief from...

Friday, 21 July 2023 14:28

  Brushing your teeth is essential for maintaining optimal oral health, but like most aspects of health, the full story is more complicated.

Friday, 21 July 2023 06:06

Are you seeking a gentle yet powerful practice that brings balance to your body and mind? Look no further than Tai Chi. 

Friday, 21 July 2023 05:40

  As the world grapples with the ongoing COVID-19 pandemic, there has been a surge of interest and concern regarding vaccines. Vaccines play a crucial role in preventing infectious diseases,...

Thursday, 20 July 2023 22:38

As the temperatures rise during the summer months, it's important to be aware of the risks associated with extreme heat.

Thursday, 20 July 2023 15:45

People who exercise only on the weekend have similar heart-health benefits as those who exercise throughout the week

Wednesday, 19 July 2023 17:42

The World Health Organisation (WHO) recently reported that around one in six couples globally are affected by infertility. For many years people tended to blame women for a couple’s infertility –...

AVAILABLE LANGUAGES

English Afrikaans Arabic Chinese (Simplified) Chinese (Traditional) Danish Dutch Filipino Finnish French German Greek Hebrew Hindi Hungarian Indonesian Italian Japanese Korean Malay Norwegian Persian Polish Portuguese Romanian Russian Spanish Swahili Swedish Thai Turkish Ukrainian Urdu Vietnamese

follow InnerSelf on

facebook icontwitter iconyoutube iconinstagram iconpintrest iconrss icon

 Get The Latest By Email

Weekly Magazine Daily Inspiration

Wednesday, 19 May 2021 08:07

For many people, the thing they’ve missed most during the pandemic is being able to hug loved ones. Indeed, it wasn’t until we lost our ability to hug friends and family did many realise just how...

Thursday, 27 July 2023 22:59

Loneliness can profoundly impact our physical and emotional health, and a new study from Tulane University has shed light on its significant role in the development of cardiovascular disease among...

Tuesday, 04 May 2021 08:32

Cognitive motor training helps in the fight against Alzheimer’s and dementia, according to new research.

Monday, 07 June 2021 08:07

Injury to the adult brain is all too common. A brain injury will often show up on brain scans as a well-defined area of damage. But often the changes to the brain extend far beyond the visible...

Friday, 14 May 2021 08:30

Fertility has declined in most industrialised countries. While the causes are largely unknown, a number of factors may contribute to declining fertility rates, including the age...

Thursday, 15 April 2021 13:22

Skin brushing is a highly effective technique for cleansing the lymphatic system. Topics covered in this article: Benefits of Skin Brushing; What type of skin brush is the best to use; How to Brush...

New Attitudes - New Possibilities

InnerSelf.comClimateImpactNews.com | InnerPower.net
MightyNatural.com | WholisticPolitics.com | InnerSelf Market
Copyright ©1985 - 2021 InnerSelf Publications. All Rights Reserved.