Why are memories attached to emotions so strong?

Date:
July 13, 2020
Source:
Columbia University Irving Medical Center
Summary:
Multiple neurons in the brain must fire in synchrony to create
persistent memories tied to intense emotions, new research has
found.



FULL STORY ========================================================================== Memories linked with strong emotions often become seared in the brain.


==========================================================================
Most people can remember where they were on 9/11, or what the weather
was like on the day their first child was born. Memories about world
events on Sept 10, or lunch last Tuesday, have long been erased.

Why are memories attached to emotions so strong? "It makes sense we
don't remember everything," says Rene' Hen, PhD, professor of psychiatry
and neuroscience at Columbia University Vagelos College of Physicians
and Surgeons. "We have limited brain power. We only need to remember
what's important for our future wellbeing." Fear, in this context, is
not just a momentary feeling but a learning experience critical to our survival. When a new situation makes us fearful, the brain records the
details in our neurons to help us avoid similar situations in the future,
or use appropriate caution.

What's still a mystery is why these memories, recorded by the brain's hippocampus, become so strong.



==========================================================================
To find out, Hen and Jessica Jimenez, an MD/PhD student at Columbia,
placed mice into new, frightening environments and recorded the activity
of hippocampal neurons that reach out to the brain's fear center (the amygdala).

The neurons' activity was also recorded a day later when the mice tried
to retrieve memories of the experience.

Unsurprisingly, neurons that respond to the frightening environment send
that information to the brain's fear center.

"What was surprising was that these neurons were synchronized when the
mouse later recalled the memory," Hen says.

"We saw that it's the synchrony that is critical to establish the fear
memory, and the greater the synchrony, the stronger the memory," Jimenez
adds. "These are the types of mechanisms that explain why you remember
salient events." How and when synchronization occurs is still unknown,
but the answer could reveal the inner workings of the brain that create lifelong memories and lead to new treatments for posttraumatic stress
disorder.

"In people with PTSD, many similar events remind them of the original frightening situation," Hen says, "and it's possible that synchronization
of their neurons has become too strong." "We're really trying to dig into
the mechanisms of how emotional memories form to find better treatments
for people with PTSD and memory disorders in general."

========================================================================== Story Source: Materials provided by
Columbia_University_Irving_Medical_Center. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Jessica C. Jimenez, Jack E. Berry, Sean C. Lim, Samantha K. Ong,
Mazen A.

Kheirbek, Rene Hen. Contextual fear memory retrieval by correlated
ensembles of ventral CA1 neurons. Nature Communications, 2020; 11
(1) DOI: 10.1038/s41467-020-17270-w ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200713144408.htm

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