The City of Lost Engrams

I was travelling back in time to an unreal place when The City appeared again after a long absence. It had been 16 months since we’d been together, and The City was not pleased. A vivid image of the security lines at the airport ushered me out of town to continue my journey to The Place That Doesn’t Exist.

A diabolical entanglement known as time has stolen memories from their homes in the dentate gyrus, lateral amygdala, precuneus, and elsewhere. These engrams hold the key to the past and the future. Without them – and their mysteriously stored representations – “we are condemned to an eternal present.”

Dwelling in the present is the path to enlightenment – “…the only moment to be alive is the present moment.”¹  There is no past and no future. The amnesiac icon H.M. was the perfect being.

And yet, avoiding the past makes everything seem unreal. So does avoidance of an unlivable present. Perhaps I am preoccupied with a future of Other Deaths. That, I am not ready for.

The dead are neglected and forgotten by other people because their windows of tolerance are closed to further mourning. Their lack of reinforcement negates my grief. The opportunities for systems consolidation² are waning.

Time. Avoidance. Neglect. They all silence my memories of The City.

I've had hundreds of involuntary visual images appear in my mind's eye like photographs, and I've documented all of them.

The images visit me rarely these days. They must be forcefully shaken from their torpor.

My passport expired 6 months ago. I finally noticed this recently.

I used to be able to cry, but now I can’t cry even though I want to.

Engram Cells

This meditation on memory, loss, and memory loss was inspired by a recent review article on memory engrams (Josselyn & Tonegawa, 2020). An “engram” is the neural substrate for storing and recalling memories. Futuristic “Inception-like” experiments in mice have shown that conditioned fear memories (tone-shock or context-shock associations) can be deleted or “inserted” by manipulating a functionally-defined class of neurons known as engram cells.

A pink engram cell alongside a white nonengram cell (modified from Josselyn & Tonegawa, 2020). Within the hippocampus, dentate gyrus cells were filled with a tracer to examine cellular anatomy (white). Engram cells active during fear conditioning were engineered to express the red fluorescent protein mCherry, which appears pink (because of overlap with the white tracer).


A primary truism of neuroscience is that memory storage is mediated by structural and synaptic plasticity. If engram cells are dedicated to preserving specific memories, the next question is: how do you define “a memory”? Most rodent studies search for engram cells associated with memories like “this location = bad”. But what about engrams formed after learning a list of words? Memories of Tomato, Attic, Pliers, Motorcycle, etc. are presumably represented by overlapping/distinctive groups of engrams distributed across multiple brain regions. What about complex autobiographical memories, like what you did on your 21st birthday? The full day (and night) of festivities consisted of many different events tied together by their temporal proximity and autobiographical significance. Studies of event perception and segmentation (Zacks, 2020) are informative in this regard:

What is the relationship between event structure in perception and that in memory? There is strong evidence that the segments that are identified during event perception correspond to the representational units in subsequent memory. First, the boundaries themselves are remembered exceptionally well. ... Second, event boundaries tended to occur at points in time when many features were changing, and the participants remembered those points better.

Life Beyond Engrams

The development of an appropriate animal model to allow selective manipulation of the whole-brain engram associated with one “birthday event” (but not the others) seems remote. Likewise, the often-involuntary nature of autobiographical memory retrieval (Bernsten, 2010) — in my case, the spontaneous appearance of visual images associated with loss and grief — is not illuminated by current engram research. Nor is the feeling of self-alienation that occurs when those memories start to fade.


Footnotes

¹ “Dwelling in the present moment
    I know this is a wonderful moment.”

   –Thich Nhat Hanh, Being Peace [PDF]

“But the Present Moment usually isn't all that great,” I say.

² Or contextual binding, depending on your degree of hippocampal dependence.


References

Berntsen D. (2010). The unbidden past: Involuntary autobiographical memories as a basic mode of remembering. Current Directions in Psychological Science 19(3):138-42.

Josselyn SA, Tonegawa S. (2020). Memory engrams: Recalling the past and imagining the future. Science 367(6473).

Zacks JM. (2020). Event Perception and Memory. Annu Rev Psychol. 71:165-191.


The Place that Doesn't Exist







I can’t remember the last time I was there. It seems like I was just there. I am always here.




All my lovers were there with me
All my past and futures
And we all went to heaven in a little row boat
There was nothing to fear and nothing to doubt

--Radiohead, Pyramid Song

(I can cry now)

02202020

New and exciting content will be available for you this weekend. Until then, please enjoy Lena Lovich and my four part series on money, religion, and numerology from 2008.


080808 (god is a number part 1)

01 1 01 1 01 (god is a number part 2)

3.14159265 (god is a number part 3)

7 (god is a number part 4)





You certainly do have a strange effect on me
I never thought that I could feel the way I feel
There's something in your eyes gives me a wild idea
I never want to be apart from you my dear
I guess it must be true
My lucky number's two

--Lena Lovich, Lucky Number

Netflix Neurology: Inside the Brain of Aaron Hernandez (for a few seconds)

from Dr. Ann McKee / Boston University

A recent addition to the Netflix “making a murderer” franchise is Killer Inside: The Mind of Aaron Hernandez. At the end of any such story, there is no single answer as to what “made” the murderer.

The story of Aaron Fernandez is still in the public eye because of his fame as a professional football player for the New England Patriots (2010-2012). He was so successful that he signed a 5 year, $40 million contract with the team in August 2012. His alleged involvement in a July 2012 double homicide came to light in 2014, after he had been charged with the June 2013 murder of his friend, Odin Lloyd. For the latter crime, he was found guilty and sentenced to life without parole. He was acquitted of the double homicide, but two days later he hanged himself with a bed sheet in his jail cell.

His brain was donated to the Boston University CTE Center. From extensive coverage in the New York Times and elsewhere, we already knew that the autopsy revealed extensive chronic traumatic encephalopathy (CTE).

If you hope to gain insight into repetitive head injury, brain pathology, and violent behavior from watching this documentary, you'll be disappointed. The 3-part series spent 5 minutes on CTE and 3 hours 15 minutes on everything else — his childhood, violent father, hurtful mother, immense athletic talent, football career, ex-con friends, girlfriend and daughter, heavy drug use, street life, weapons collection, paranoia, alleged shootings, alleged same-sex relationships, arrests, murder trials, conviction, appeal, recorded jailhouse telephone conversations, outwardly professed homophobia, death by suicide, and numerous interviews with friends and former players.

Much of this material was pruient and unnecessary, especially the speculations about his hidden sexual orientation and how this might have fueled his anger.


Prosecution Considered a “Fear of Outing” Motive

This argument was preposterous and a rarity in the history of violence involving the LGBTQ community: Hernandez supposedly feared that his friend would reveal his secret life as a bisexual man, so he killed Lloyd to preserve his image as a hyper-masculine heterosexual man. This baffling obsession with sexuality is distracting and dangerous, as aptly explained by D. Watkins:

There's no evidence proving that Hernandez's sexuality made him a killer. So why is the newly resurfaced Hernandez conversation centered around his sex life? Probably because sex is juicy, forbidden and learning that Hernandez may have been gay provides the consumers with content for endless hours of gossip about what public figures do in their personal lives.

Fortunately, this argument was not allowed at trial.


The Potential Role of CTE Was an Afterthought

A Rolling Stone interview with director Geno McDermott revealed the project began as a 90 minute documentary initially presented at DOC NYC in 2018. Netflix was interested in expanding the doc into a multi-part series. The gay angle emerged when high school friend/lover Dennis SanSoucie agreed to an on-camera interview. Other additions included newly available recordings of prison phone calls, and a coda about CTE, the neurodegenerative disease that may be associated with repeated concussions in high-impact sports (in concert with other poorly delineated factors).

At the very end of Killer Inside, self-serving celebrity defense attorney Jose Baez spoke about the family's decision to donate Aaron's brain to the CTE Center at Boston University.

Dr. Ann McKee with the brain of Aaron Fernandez

Dr. McKee said Hernandez had very advanced disease for a 27 year old:

...and not only was it advanced microscopically, especially in the frontal lobes which are very important for decision-making, judgment and cognition, this would be the first case we've ever seen of that kind of damage in such a young individual.

I can say this is substantial damage that undoubtedly took years to develop. This is not something that is developed acutely or just in the last several years. I imagine these changes had been evolving over maybe even as long as a decade.

Then we see interviews with non-experts, who make causal connections between Aaron's CTE and his erratic, violent, tragic behavior. Worst of all is sleazy lawyer Jose Baez, who drummed up business for other players to sue the NFL under false pretenses (there is currently no way to accurately diagnose CTE in living persons).

Why didn't Aaron's brother, who grew up with the same abusive father and played football for many years, become a murderer? I'll let former NFL player Jermaine Wiggins have the last word:

My thoughts to people who think that CTE was somehow involved, I think that's an absolute cop out. There are thousands of former NFL players out there that might have dealt with concussions, I've dealt with them. So to use that as a cop out? I'm not... no, no. C'mon, we're smarter than that, people.”

Further Reading

Is CTE Detectable in Living NFL Players?
– this 2013 post is still true today

Brief Guide to the CTE Brains in the News. Part 1: Aaron Hernandez