the gag reel

I know memory isn't a passive record of events.  It's more like an ongoing re-construction. When this happens, I consistently get the order of things wrong.  I often confuse what happened one time for something that happened another time.  Last night I was watching a gag reel from season five of Parks and Recreation. In an early scene, Andy asks his young wife April if she's pregnant. April responds saying: "Nooo, we've talked about this ..and what do I always tell you? We're going to wait till we're 50 to have children ..!" In another scene, Andy and April are giving Ben advice for a successful marriage. Andy asks April what other tips they can give him (that she heard from a friend). April replies: "She said 'don't pull out till I scream'!" Now, at the end of the reel, what do I remember?  In the first scene where they talk about having children ..I remember April saying: "Nooo, we've talked about this ..and what do I always tell you? 'Don't pull out till I scream'!" I put the dialogue from the other scene  here. It wasn't until I replayed the gag reel that I realized my mistake. Although my recollection didn't follow the actual order of events ..it made sense and even retained some of it's humor.  Perhaps we remember semantic-relationships better than chronological order.

false memory

“Memory is not a passive record of things past. It's more like an ongoing construction-site, integrating and revising the past with events from the present and predictions about the future.”  [link]

How to plant a false memory by Dr. Susumu Tonegawa [link]: I’m skeptical. How is it possible to know what’s going on inside the head of a mouse ..let alone tell whether it’s true or not. I’m also intrigued. They say the fabric of memory is pliable and self-serving. It can be revised by the simple act of re-hashing things. Psychologist Elizabeth Loftus used to demonstrate this with eyewitness testimony. Neuroscientists have now replicated it with mice in a maze. Here’s how:

1. They narrow down a set of brain cells that get activated whenever a mouse enters a new location. Unfamiliar territory evokes a ‘neo-phobic’ response, which adds staying power to novel experience.
2. Then they create a new memory by stimulating the same set of cells and delivering an unpleasant jolt when the mouse enters a neutral part of the maze. The mouse ‘re-lives’ the experience of being in the location it explored before and couples it with the jolt. How do they know? The mouse avoids the location like never before.

They say memory serves as a road map to the future. However humans can play pretty loose with it .. reminiscing or ruminating about things ..which may make us more prone to revising the past. I don’t know if this has anything to do with it but I often recollect scenes from movies I enjoy. Lately I’ve been watching a lot of French films with the actress Audrey Tautou ..who I just adore. I also saw her in the movie ‘Da Vinci Code’ last night. This morning when Audrey Tautou popped into my head ..I mistook her for the character she plays in the movie. A character of potentially game-changing consequence to humanity. It felt eerie. It was just a flash but I’m wondering if this isn’t also some kind of false memory. Perhaps I’m overthinking it. I often blur the distinction between fantasy and reality. I know I confuse scenes from the movies with episodes from my past.

Navigating memory

“Here we propose that mechanisms of memory and planning have evolved from mechanisms of navigation in the physical world and hypothesize that the neuronal algorithms underlying navigation in mental space are fundamentally the same as those that underlie navigation in  physical space.”

From: Memory navigation and theta rhythm in the hippocampus [link]

György Buzsáki and Edvard I Moser

Eyewitness testimony

Since 1975, Elizabeth Loftus has conducted research into the integrity of human memory. Her studies show that memory is not a video recording of things past. It’s suggestible and subject to laws of perception ..especially when we rely on it for eyewitness testimony [ link ].  Courtroom proceedings  back her claims. Convictions have been overturned due to faulty eyewitness testimony. Crimes are generally chaotic and the experience .. traumatic. In addition, the process of identifying suspects from a lineup or photo spread can be biased. The state of Oregon is the first to establish standards, based on these findings, to determine what qualifies as admissible evidence from eyewitness testimony [ link ]. For one, the eyewitness needs to be in a position to objectively observe the perpetrator during the commission of a crime ..not wounded or staring down the barrel of a gun. Two, lineups need to be conducted by someone who doesn’t know the identity of the suspect. And three, photos need to be presented sequentially, one at a time, the way we ordinarily run into people on the street ..not all at once.

Imagining things

People store and retrieve information based on self-interest, feelings and mirroring – or mentally simulating an activity. Kind of like watching a tennis match in preparation for a game. When presented with lists of character traits (adventurous, brave, compassionate) participants were asked one of five questions: 

1. what does it rhyme with (phonetic elaboration) 

2. what does it mean (semantic elaboration) 

3. can you identify with it (semantic self-referential processing) 

4. have you ever acted that way (episodic self-referential processing) 

5. can you imagine yourself acting that way now (self-imagining) 

Turns out question 5 (self-imagining) boosts recall more than any of the other questions [ link ].

PTSD

Researchers in Europe have found that a gene, linked to improved memory performance ..also increases susceptibility to PTSD [ link ] “..in dramatic fashion, a gene variant responsible for differences in brain activity during memory encoding can also lead to increased risk of developing PTSD in response to catastrophe.” According to Neurobiologist James McGaugh at the University of California, Irvine “It’s well known that emotional arousal enhances memory consolidation, which can be a contributing factor to PTSD ..these findings provide genetic support for this hypothesis.”

Neuropharmacology of ketamines

Glutamic acid is the most abundant excitatory neurotransmitter in the nervous system. When released, it binds with the NMDA-receptor site to produce long-term potentiation (LTP).

LTP improves synaptic transmission by increasing the cell’s sensitivity to incoming signals, which allows for neuro-plasticity, learning and memory. 

NMDA (N-Methyl-D-aspartic acid) is a synthetic amino acid, which acts as an agonist at the NMDA-receptor site .. mimicking the action of glutamic acid (excitatory). 

Ketamine is an NMDA-receptor antagonist. It blocks the action of glutamic acid and acts as an analgesic at low doses. At high doses, ketamine produces a disassociative state, characterized by a sense of detachment from the physical body (depersonalization) and the external world (derealization). Users may experience what is called the “K-hole”, a period of dissociation and intense hallucinations where they experience other worlds or celestial-like dimensions ..while being completely unaware of their individual identities or the external world. Users have reported flying .. connecting to other users and objects in the cosmos ..and sharing hallucinations and thoughts with adjacent users. They feel as though their perceptions are located so deep inside the mind that the real world seems distant (hence the use of a “hole” to describe the experience).

Memory: Users do not remember the experience after regaining consciousness, in the same way that a person may forget a dream. Owing to the role of the NMDA receptor in long-term potentiation, this may be due to disturbances in memory formation. The ‘re-integration” process is slow, and the user gradually becomes aware of surroundings. At first, users may not remember their own names, or even know that they are human, or what that means. They may not be aware they have a body at all.  Ketamine is also used with local anesthetics for its amnesia action. It effectively wipes out memory for the trauma associated with severe injury and surgery.

Temporal binding

The hippocampus is a brain structure that plays a major role in the process of memory formation. It is not entirely clear how the hippocampus manages to string together events that are part of the same experience but are separated in time. Newly published research finds that there are neurons in the hippocampus that encode the sequence of events that make up experience [link] and [link].

Multi story memory

Presented to the seminar in
COGNITIVE SCIENCE

It wasn’t long ago that psychologists regarded memory as a single-thread of stimulus-response associations; strengthened by repetition. What went on between the time information was stored and retrieved was terra incognito. Memory was commonly thought to be a passive record of stimulus-events. Once events were stored, they became a reliable part of memory. The information was always there; forgetting was blamed on a failure of retrieval. The associative principles of memory no longer apply. They fail to capture clinical reports of patients with aphasia or Alzheimer’s. Aphasia patients can usually remember current events, but they forget long-term information such as the meaning of words or the names of familiar objects. On the other hand, Alzheimer’s patients can remember long-term information, such as the meaning of words, but they forget recent events such as a visit by a relative or their arrival at the clinic. These observations suggest different types of memory at work. Some temporarily hold events in our immediate surroundings while others preserve them on a more lasting basis.   

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