Metropolitan Digital

  • Written by Jacek Debiec, Assistant Professor / Department of Psychiatry; Assistant Research Professor / Molecular & Behavioral Neuroscience Institute, University of Michigan

Most of what you experience leaves no trace in your memory. Learning new information often requires a lot of effort and repetition – picture studying for a tough exam or mastering the tasks of a new job. It’s easy to forget what you’ve learned, and recalling details of the past can sometimes be challenging.

But some past experiences can keep haunting you for years. Life-threatening events – things like getting mugged or escaping from a fire – can be impossible to forget, even if you make every possible effort. Recent developments in the Supreme Court nomination hearings and the associated #WhyIDidntReport action on social media[1] have rattled the public and raised questions about the nature, role and impact of these kinds of traumatic memories.

Leaving politics aside, what do psychiatrists and neuroscientists like me[2] understand about how past traumas can remain present and persistent in our lives through memories?

Bodies respond automatically to threat

Imagine facing extreme danger, such as being held at gunpoint. Right away, your heart rate increases. Your arteries constrict, directing more blood to your muscles, which tense up in preparation for a possible life-or-death struggle. Perspiration increases, to cool you down and improve gripping capability on palms and feet for added traction for escape. In some situations, when the threat is overwhelming, you may freeze and be unable to move.

Threat responses are often accompanied by a range of sensations and feelings. Senses may sharpen, contributing to amplified detection and response to threat. You may experience tingling or numbness in your limbs, as well as shortness of breath, chest pain, feelings of weakness, fainting or dizziness. Your thoughts may be racing or, conversely, you may experience a lack of thoughts and feel detached from reality. Terror, panic, helplessness, lack of control or chaos may take over.

These reactions are automatic and cannot be stopped once they’re initiated, regardless of later feelings of guilt or shame about a lack of fight or flight.

Brains have two routes to respond to danger

Biological research over the past few decades has made significant progress in understanding how the brain responds to threat. Defense responses are controlled by neural systems that human beings have inherited from our distant evolutionary ancestors.

Memories of trauma are unique because of how brains and bodies respond to threat The amygdala – in red – is involved in emotion processing. Life Science Databases, CC BY-SA[3][4]

One of the key players is the amygdala[5], a structure located deep in the medial temporal lobe, one on each side of the brain. It processes sensory threat information and sends outputs to other brain sites, such as the hypothalamus, which is responsible for the release of stress hormones, or brain stem areas, which control levels of alertness and automatic behaviors, including immobility or freezing.

Research in animals and more recently in people suggests the existence of two possible routes[6] by which the amygdala receives sensory information. The first route, called the low road, provides the amygdala with a rapid, but imprecise, signal[7] from the sensory thalamus. This circuit is believed to be responsible for the immediate, unconscious responses to threat.

The high road is routed through the cortical sensory areas[8] and delivers more complex and detailed representations of threat to the amygdala. Researchers believe the high road is involved in processing the aspects of threats of which a person is consciously aware[9].

The two-roads model explains how responses to a threat can be initiated even before you become consciously aware of it[10]. The amygdala is interconnected with a network of brain areas, including the hippocampus, the prefrontal cortex and others, all of which process different aspects of defense behaviors. For example, you hear a loud, sharp bang and you momentarily freeze – this would be a low road-initiated response. You notice somebody with a gun, immediately scan your surroundings to locate a hiding spot and escape route – these actions wouldn’t be possible without the high road being involved.

Two kinds of memories

Traumatic memories are intensely powerful and come in two varieties.

When people talk about memories, most of the time we refer to conscious or explicit memories. However, the brain is capable of encoding distinct memories in parallel for the same event – some of them explicit and some implicit or unconscious.

An experimental example of implicit memories is threat conditioning[11]. In the lab, a harmful stimulus such as an electric shock, which triggers innate threat responses, is paired with a neutral stimulus, such as an image, sound or smell. The brain forms a strong association between the neutral stimulus and the threat response. Now this image, sound or smell acquires the ability to initiate automatic unconscious threat reactions – in the absence of the electric shock.

It’s like Pavlov’s dogs salivating when they hear the dinner bell, but these conditioned threat responses are typically formed after a single pairing between the actual threatening or harmful stimulus and a neutral stimulus, and last for life. Not surprisingly, they support survival. For example, after getting burned on a hot stove, a child will likely steer clear of the stove in order to avoid the harmful heat and pain.

Studies show that the amygdala is critical[12] for encoding and storing associations between a harmful and neutral stimuli, and that stress hormones and mediators – such as cortisol and norepinephrine – play an important role in the formation of threat associations.

Memories of trauma are unique because of how brains and bodies respond to threat One detail – the buzz of streetlights, a truck’s squealing tires – can trigger the memory of a traumatic accident. Ian Valerio/Unsplash, CC BY[13][14]

Researchers believe traumatic memories are a kind of conditioned threat response[15]. For the survivor of a bike accident, the sight of a fast approaching truck resembling the one that crashed into them may cause the heart to race and skin to sweat. For the survivor of a sexual assault, the sight of the perpetrator or someone who looks similar may cause trembling, a feeling of hopelessness and an urge to hide, run away or fight. These responses are initiated regardless of whether they come with conscious recollections of trauma.

Conscious memories of trauma are encoded by various sites in the brain which process different aspects of experience. Explicit memories of trauma reflect the terror of the original experience and may be less organized than memories acquired under less stressful conditions. Typically they’re more vivid, more intense and more persistent[16].

After the memories are made

Memories are biological phenomena and as such are dynamic. Exposure to cues that trigger the recall or retrieval of traumatic memories activates the neural systems that are storing the memories[17]. This includes electrical activation of the neural circuits, as well as underlying intracellular processes.

Reactivated memories are susceptible to modification. The character and direction of this modification depends on the circumstances of the person recalling the memory. Retrieval of implicit or explicit traumatic memories is usually associated with high levels of stress. Stress hormones act on the activated brain circuits and may strengthen the original memory[18] for trauma through a phenomenon known as memory reconsolidation.

There are clinical strategies to help people heal from emotional trauma[19]. One critical factor is the sense of safety. Retrieval of traumatic memories under safe conditions when levels of stress are relatively low and under control enables the individual to update or reorganize the trauma experience. It’s possible to link the trauma to other experiences and diminish its destructive impact. Psychologists call this post-traumatic growth[20].

It is an ethical imperative to consider the circumstances under which traumatic memories are recalled, whether in the course of therapy, during police investigations, court hearings or public testimonies. Recalling trauma may be a part of the healing process or may lead to re-traumatization, persistence and continued detrimental effects from traumatic memories.

References

  1. ^ #WhyIDidntReport action on social media (www.bbc.com)
  2. ^ like me (scholar.google.com)
  3. ^ Life Science Databases (commons.wikimedia.org)
  4. ^ CC BY-SA (creativecommons.org)
  5. ^ key players is the amygdala (doi.org)
  6. ^ existence of two possible routes (doi.org)
  7. ^ rapid, but imprecise, signal (doi.org)
  8. ^ routed through the cortical sensory areas (doi.org)
  9. ^ of which a person is consciously aware (doi.org)
  10. ^ before you become consciously aware of it (doi.org)
  11. ^ threat conditioning (doi.org)
  12. ^ amygdala is critical (doi.org)
  13. ^ Ian Valerio/Unsplash (unsplash.com)
  14. ^ CC BY (creativecommons.org)
  15. ^ traumatic memories are a kind of conditioned threat response (doi.org)
  16. ^ more vivid, more intense and more persistent (doi.org)
  17. ^ activates the neural systems that are storing the memories (doi.org)
  18. ^ may strengthen the original memory (doi.org)
  19. ^ clinical strategies to help people heal from emotional trauma (www.traumacenter.org)
  20. ^ post-traumatic growth (www.taylorfrancis.com)

Authors: Jacek Debiec, Assistant Professor / Department of Psychiatry; Assistant Research Professor / Molecular & Behavioral Neuroscience Institute, University of Michigan

Read more http://theconversation.com/memories-of-trauma-are-unique-because-of-how-brains-and-bodies-respond-to-threat-103725

Metropolitan republishes selected articles from The Conversation USA with permission

Visit The Conversation to see more

Entertainment News

How to Create a Melody on the Piano

Have you ever wondered what it would be like to be able to write a song? Maybe you’ve wondered how anybody goes about writing a song? Once you understand how music works, you can use building b...

News Company - avatar News Company

MUSIC SENSATION WILLIE J RELEASES NEW SINGLE TO AID CORONA RELIEF

In the midst of the devastating COVID-19 pandemic, the release of “In the Morning” on Pure Mission Entertainment – the label he partners on with Aaron Emig - follows on the heels of the global s...

Tom Estey - avatar Tom Estey

Expert Advice: Indie Record Producing and Engineering

My career as an independent artist evolved out of my career as an entrepreneur and restaurant owner. I moved to from my hometown of Boston Atlanta in 2013 and opened my soul food restaurant Soul D...

Darrell Kelley - avatar Darrell Kelley

Weight of The World

When the calm of the world is at stake, and every message of hope is crucial to our collective peace of mind and the endurance of the human spirit, it’s not only possible, but essential to present any...

Tom Estey - avatar Tom Estey

DARRELL KELLEY “The Coronavirus”

Even though I have been releasing tracks and albums since 2018, I never considered myself an artist until I started getting responses from people telling me that my songs were resonating with them. ...

DARRELL KELLEY - avatar DARRELL KELLEY

A TIME TO GRIEVE, & A TIME TO GIVE - Covid-19

During these tumultuous times, people are feeling a loss that is akin to grieving.  Grieving for their former lives and ways and it is unclear when things will return to “normal.”  Grieving for th...

Stephanie Hochman of My Luv Notes - avatar Stephanie Hochman of My Luv Notes

Music During the COVID 19

On Saturday, March 7th, the first throngs of bikers began rumbling their way toward Daytona Beach for another year of its infamous annual event – Bike Week. During the week, the endless growl of the...

Hannah Summer of GREYE - avatar Hannah Summer of GREYE

Stephen Wrench “Life’s a Sham” Album

On April 14th the single “Life’s a Sham” will be released. Some songs take months and even years to write but “Life’s a Sham” was written in 15 minutes. After writing the lyrics I picked up my gui...

Stephen Wrench - avatar Stephen Wrench

Darrell Kelley perfectly meets our unique, challenging moment in history with “The Coronavirus”

“The Coronavirus”   With the release of his powerful, no holds barred song “The Coronavirus,” Darrell Kelley perfectly meets our unique, challenging moment in history by addressing our strange ne...

Tom Estey - avatar Tom Estey

Metropolitan Business News

How to make overseas transfers easier?

Mainstream banks can charge as much as $20 just to process a basic international money transfer. Fortunately, today people are not doomed to handling personal finances only through mainstream gl...

News Company - avatar News Company

The flourishing international market of fragrance and perfume

There is something special and unique about the art of fragrance. This is a big world and there are quite literally a lot of smells around at any given time. In fact, as one of the five human senses i...

News Company - avatar News Company

Impact of good marketing on sales

Sales and marketing are brothers as they go hand and in hand. The job of both of these departments is to generate revenue so that an organization can make money. A company that does not generate rev...

News Company - avatar News Company

7 effective tips for increasing sales in retail

It seems that retailers have drawn a difficult lot in the 21st century: competition from online retail is growing steadily. After all, Internet retailers can sell your products at significantly lowe...

News Company - avatar News Company

10 Reasons to Use Labels

People cannot stop biting their nails, considering the messy condition of their homes. You open your kitchen drawer to grab some utensils, but instead, you take a glance at toys lying inside that dr...

News Company - avatar News Company

15 ways to encourage your office employees

We often get so busy managing our companies and business that we forget about the most important resource that is making our business reach new height every day, our employees. Support of the manage...

News Company - avatar News Company

Holidays

5 COOL GADGETS TO CARRY FOR A SAFE TRIP

Are you planning to go on a trip? Possibly, you do not know what things are most necessary on a trip. In this article, we will guide you through some important tips. These tips help you to...

News Company - avatar News Company

New Baggage Regulations to Help Aussie Parents Travel with Infants

Travelling around the globe has never been easy, especially when infants tag along for the trip. One of the main issues that parents often have to deal with is the need to bring extra item...

News Company - avatar News Company

Maya Beach Opens to Tourists

Despite recent reports that Southern Thailand's famous Maya Beach will close for three months this year, in fact no decision to this effect has been made by Thai authorities. Phi Phi Nati...

Maevadi Rosenfeldt - avatar Maevadi Rosenfeldt



METRO DIGITAL NEWS

Breaking News & Opinion