Scientists have now found the engram, the physical trace of memory in the brain. […]

Decades of scientific dogma asserted that engrams exist only in vast webs of connections, not in a particular place but in distributed neural networks running widely through the brain. Yet a series of pioneering studies have demonstrated that it is possible to lure specific memories into particular neurons, at least in mice. If those neurons are killed or temporarily inactivated, the memories vanish. If the neurons are reactivated, the memories return. These same studies have also begun to explain how and why the brain allocates each memory to a particular group of cells and how it links them together and organizes them—the physical means by which the scent of a madeleine, the legendary confection that sparked Marcel Proust’s memory stream, leads to remembrance of things past. […]

“We have now gotten to the point that we know enough about memory and how memories are formed that we can actually find the engram, and by finding it, we can manipulate it,” says neurobiologist Alcino Silva.

{ Discover | Continue reading }

image { Stefano Colombini }

The way that children reason about the world, there’s a lot of good evidence to suggest that there are domains of knowledge: physical, reasoning about the physical world; biological, reasoning about the living world; and reasoning about the psychological world. Those three domains are the physics, the biology and the psychology, and are deemed to cover the majority of what we do when we’re thinking about concepts. […]

This is work I’ve done with Paul Bloom. We initially started looking at sentimental objects, the emergence of this bizarre behavior that you find in children in the West. They form these emotional attachments to blankets and teddy bears and it initially starts off as an associative learning type of situation where they need to self-soothe, because in the West we typically separate children, for sleeping purposes, between one and two years of age. In the Far East they don’t, they keep children well into middle childhood, so they don’t have as much attachment object behavior. It’s common, about three out of four children start off with this sort of attachment to particular objects and then it dissipates and disappears.

What Paul and I are interested in is whether or not it was the physical properties of the object or if there was something about the identity or the authenticity of the object which is important. We embarked on a series of studies where we convinced children we had a duplicating machine, and basically we used conjuring tricks to convince the child that we could duplicate any physical object. We have these boxes which looked very scientific, with wires and lights, and we place an object in one, and activate it, and after a few seconds the other box would appear to start up by itself and you open it up and you see you’ve got two identical objects. The child spontaneously said, “Oh, it’s like a copying machine.” It’s like a photocopier for objects, if you like. Once they’re in the mindset this thing can copy, we then test what you can get away with. They’re quite happy to have their objects, their toys copied, but when it comes to a sentimental object like a blanket or a teddy bear, then they’re much more resistant to accepting the duplicate. […]

Also, we’re getting into the territory of authenticity and identity. There are some fairly old philosophical issues about what confers identity and uniqueness, and these are the principles, quiddity and haecceity. I hadn’t even heard of these issues until I started to research into it, and it turns out these obscure terms come from the philosopher Duns Scotus. Quiddity is the invisible properties, the essence shared by members of a group, so that would be the ‘dogginess’ of all dogs. But the haecceity is the unique property of the individual, so that would be Fido’s haecceity or Fido’s essence, which makes Fido distinct to another dog, for example.

These are not real properties. These are psychological constructs, and I think the reason that people generate these constructs is that when they invest some emotional time or effort into an object, or it has some significance towards them, then they imbue it with this property, which makes it irreplaceable, you can’t duplicate it. […]

The sense of personal identity, this is where we’ve been doing experimental work showing the importance that we place upon episodic memories, autobiographical memories. […] As we all know, memory is notoriously fallible. It’s not cast in stone. It’s not something that is stable. It’s constantly reshaping itself. So the fact that we have a multitude of unconscious processes which are generating this coherence of consciousness, which is the I experience, and the truth that our memories are very selective and ultimately corruptible, we tend to remember things which fit with our general characterization of what our self is. We tend to ignore all the information that is inconsistent. We have all these attribution biases. We have cognitive dissonance. The very thing psychology keeps telling us, that we have all these unconscious mechanisms that reframe information, to fit with a coherent story, then both the “I” and the “me”, to all intents and purposes, are generated narratives.

{ Bruce Hood/Edge | Continue reading }

photo { Todd Fisher }

A good memory is typically seen as a powerful advantage, an aid to intelligence and socializing. But when experience is traumatic, this asset may become a serious liability, according to new research on survivors of the Rwandan genocide.

Researchers at the University of Basel in Switzerland studied a gene for a protein called PKCA, which is known to be involved in the encoding of emotional memories. […]

According to the study, the findings point to a “genetic link between the predisposition to build strong memory and the risk for post-traumatic stress disorder.”

The research also adds to increasing evidence that many “positive” genes also have a downside — and similarly, many “negative” ones have an upside. For example, one gene linked with a tendency for children to share treats with others is also linked to ADHD and later in life, promiscuity and addiction.

{ Time | Continue reading }

photo { Juergen Teller }

Well-meaning friends and family members may suggest that you have a couple of drinks after living through a stressful event. A friend of mine had a bike accident recently that sent her over a car door and miraculously left her with only a few bruises. Having a couple of drinks immediately after this will of course dull her nerves, since ethanol is an anxiolytic. But is it really a good idea to get tipsy (or worse) after living through a stressful event?

lt’s well known that acute stress modulates memory in a powerful way. People who have lived through a traumatic event will often either have either perfect photographic memory of the event or partial or total amnesia. Untreated, exposure to a traumatic event can lead to post-traumatic stress disorder (PTSD), which causes long-term problems. There exist preventive treatments that, when applied immediately after the traumatic event, have been shown to decrease the likelihood of getting PTSD. This includes antagonists of adrenaline and NMDA receptors; this messes with the acquisition of memory.

Of course good ol’ beer will mess with the acquisition of memory; that’s why people get brownouts and blackouts. It is also an antagonist of NMDA receptors (among many other systemic effects). So given that alcohol is an anxiolytic and that it causes amnesia, it doesn’t seem such a stretch to think that having a beer right after very a stressful event (within the next, say, 6 hours) will decrease the likelihood of long-term negative consequences (say, developing a phobia of biking).

This is of course the sort of hypothesis that is very hard to get funding to test. We do know that PTSD sufferers frequently turn to alcohol after their trauma and that this negatively affects outcome. And drowning your sorrows is never the solution. To be clear, taking an anxiolytic and amnesiac acutely to avoid acquiring a potentially adverse memory of a traumatic event and taking it in a sustained way after the memory is consolidated to drown it out are two completely different things.

{ xcorr | Continue reading }

artwork { Joel Shapiro, Untitled, 1980 }

Brain neuroimaging studies continue to outline the structural and functional abnormalities in disorders of mood. A relatively consistent finding has been a reduced volume of the brain hippocampus in major depressive disorder. Studies of hippocampal volume in the less common bipolar disorder have been inconsistent–some studies have found reduced hippocampal volumes while others have not.

The hippocampus is an important brain region to understand in the mood disorders. The hippocampus has a key role in memory. Patients with mood disorders commonly display impairments in mood including deficitis in autobiographical memory. Unipolar depression appears to increase risk for later development of Alzheimer’s disease. Hippocampal volume reduction is a common finding in Alzheimer’s disease. (…)

Lithium is noted to have significant neuroprotective effects.  (…) It is possible that bipolar patients treated with lithium may experience less hippocampal atrophy than those not treated with lithium.

{ Brain Posts | Continue reading }

charcoal on paper { Marius de Zayas, John Marin and Alfred Stieglitz, ca. 1912–13 }

Among the most surprising discoveries about memory has been the realisation that remembering a past event is not like picking a DVD off the shelf and playing it back. Remembering involves a process of reconstruction. We store assorted features of an event as representations that are distributed around the brain.

In simple terms, visual features are represented near the back of the brain in the areas specialised for visual processing; sounds in auditory processing regions close to the ears; and smells in the olfactory system that lies behind the nose.

To experience the rich, vivid “re-living” of a past event that is remembering, we fit these features together into a representation of what took place.

A lot of stuff happens in our lifetimes, and so it makes sense that our brains would have evolved some efficient memory strategies. We don’t try to remember every single event in its entirety. Instead, we store the elements of an event, and put them together in different ways to make different memories. The downside is that similar events that share a number of features may be more difficult to remember.

Our experiment was designed to investigate this effect.

{ Guardian | Continue reading }

artwork { Sougwen Chung | Thanks Tim }

How to actually be good at rote memorization. A group of psychologists decided to help the kids out by examining the optimal duration for studying a particular item. (…)

Subjects who avoided the longest (16s) and shortest (1s) durations retained more information when testeed after 5 minutes and when tested after 2 days. (…)

Performance was much better for intermediate (e.g., 4 s) presentation durations.

I bring up this study not because it’s crucial for our education system, but because in the future every part of our lives will be designed based on this type of research. Advertisements, online dating profiles, and all manner of printed instructions will be optimized for the perfect exposure length.

{ peer-reviewed by my neurons | Continue reading }

When we watch a show on stage, TV or movie, we do the little trick of suspending disbelief. We do not believe what we are experiencing but we treat the content ‘as if we believed it’ for the duration of the show. We can re-enter that disbelieved experience if we choose, as if it were a memory of something that actually happened. The show can have lasting effects on how we view the world and interact with others. It has all the hallmarks of a really personal experience except that we know it is fictional. (…) What is the difference between this sort of memory and what we call false-memory? It is only the believe that the events remembered actually happened to us.

According to a recent paper, belief and memory are separate processes. We can have: memories that we believe were events, memories that we do not believe were events, beliefs about events that we do not remember, and events that we neither believe nor remember. (…)

The authors found that belief is easier to modify than memory. It is easier to create a false belief in a subject that it is to create a false memory. And likewise, it is easier to destroy a false belief than a false memory.

{ Thoughts on thoughts | Continue reading }

Several studies suggest that memories can be pharmaceutically dampened. For example, researchers recently showed that a drug called ZIP causes cocaine-addicted rats to forget the locations where they had regularly been receiving cocaine. Other drugs, already tested in humans, may ease the emotional pain associated with memories of traumatic events.

Many are alarmed by the prospect of pharmaceutical memory manipulation. In this brief comment, I argue that these fears are overblown. Thoughtful regulation may someday be appropriate, but excessive hand-wringing now over the ethics of tampering with memory could stall research into promising methods of preventing and treating post-traumatic stress.

{ SSRN | Continue reading }

photo { Nigel Shafran, Moonflower, 1990 }

The hippocampus is the part of the brain that’s responsible for learning, storing memories and associating them with feelings and emotions. Within the hippocampus lies the dentate gyrus, which is where adult neurogenesis takes place — the formation of new neurons throughout adulthood. The middle layer of the dentate gyrus contains a type of neurons called granule cells. These are constantly generated and take a few weeks to develop and integrate in the dentate gyrus network.

Marin-Burgin et al. asked the following question:

Is it solely the continuous addition of new neurons to the network that is important, or are there specific functional properties only attributable to new granule cells (GCs) that are relevant to information processing?

{ Chimeras | Continue reading }

Very little research has investigated whether smells really do evoke vivid and emotional memories, more than other sensory cues. What follows is a new, rare attempt. (…)

“It could be argued that a necessary implication of the Proust phenomenon is that odors are more effective triggers of emotional memories than other-modality triggers,” the researchers said. “Under such strong assumptions the results reported here do not confirm the Proust phenomenon. Nonetheless, our findings do extend previous research by demonstrating that odor is a stronger trigger of detailed and arousing memories than music, which has often been held to provide equally powerful triggers as odors.”

{ BPS | Continue reading }

photo { Stephanie Gonot }

Many of us cling to the notion that memory is a reliable record and trawling through it can be similar to flipping through an old photo album. But what about the memories - sometimes vivid in nature - of things that never were?

Examining the false stories that we can create for ourselves is the aim of a new initiative led by artist Alasdair Hopwood. As part of a residency at the Anomalistic Psychology Research Unit led by Chris French at Goldsmiths College, University of London, Hopwood aims to explore what false memories reveal about our sense of identity.

To do this, he has created the False Memory Archive, a collection of people’s fabricated recollections either jotted down after talks he has given or submitted online at the project’s website. (…)

For Hopwood, examining the ways we deceive ourselves through memory is perhaps a natural progression. He has worked with fellow artists as part of the WITH Collective on projects that expose and poke fun at the many ways we style our public selves. “Identity is not fixed,” he says. Instead, it shifts depending on the company we are in, and even the format of the interaction - be it social media or in person. We’re extraordinarily preoccupied with sculpting our identities, as the glut of self-help books and pseudoscientific methods for personal development demonstrates.

{ NewScientist | Continue reading }

photo { Dennis Lan }