Thread: What are memories?

Hi all, just been thinking recently about what memories actually are and how they might work. In today's understanding, memories are not formed by neurons, but by synapses (unless there is going to be an even smaller component proposed). Me being able to remember that 2+2 = 5 comes from George Orwell's 1984 novel, seems like a strength of connection between the numbers 2,5, 1984, the logical concept of addition, result, the name George Orwell, and what a novel is. Does that mean that memories are a certain connection between multiple items and concepts, each represented by one or more synapses? How does a synapse, or many of them, represent a number such as 2, or what a novel means in the first?

I have a suspicion that the answer may well be found in the mirror neural network. We know it is responsible for empathic emotion, which rest on recognition of the circumstances in which the events and their emotional attachments are first experienced.

Mirror neuron
http://en.wikipedia.org/wiki/Mirror_neuron

Not only can this network be fooled, but it tries to make sense out of a chaotic even misleading circumstance. Can you imagine a 7' lifesize slug crawling over a concrete bench in the middle of the citytoward a woman sitting on that bench?

http://ts3.mm.bing.net/th?&id=HN.608...d=1.9&rs=0&p=0 view at 400x

You may want to check out Bayesian inference,
Bayesian inference - Wikipedia, the free encyclopedia

and Bayesian probability,
Bayesian probability - Wikipedia, the free encyclopedia

They're certainly involved in a type of memory, recognition, though it would be interesting to see if these neurons function effectively in socially isolated individuals, as this would suggest that human beings are born with this recognition memory. Perhaps at the smaller level, memory is merely biochemical changes in synaptic firing, making it easier for the action potential to be reached, and therefore a memory is just a strong connection between objects/concepts. Still at a loss as to how these objects/concepts are physically represented.

Originally Posted by Curiosity

They're certainly involved in a type of memory, recognition, though it would be interesting to see if these neurons function effectively in socially isolated individuals, as this would suggest that human beings are born with this recognition memory. Perhaps at the smaller level, memory is merely biochemical changes in synaptic firing, making it easier for the action potential to be reached, and therefore a memory is just a strong connection between objects/concepts. Still at a loss as to how these objects/concepts are physically represented.

If I understand correctly, the mirror neural network is not functional in autistic individuals, or may function differently and present difficulty relating to ordinary behavior. Interestingly, some autistic individuals are expert with computers and there is a famous case of a girl who spent many years in an institution for the mentally impaired, until someone gave her a computer. She now travels around the world telling her story via texting. Turns out she posesses a high IQ, but was unable to translate her experiences by any other means but the computer. Remarkable!

IMO, all of this suggests to me that memories are formed as they are experienced. Traumatic events leave a lasting imprint of the circumstance and emotional reaction to the experience. When we see someone hit their thumb with a hammer, we cringe and generate the same chemicals in our brain as the person who actually feels the pain. Seems to me we must remember similar events in our own lives to be able to feel an empathic response to the situation.

Perhaps recognition of danger may have become hardwired at a very basic level, because it may well be an evolutionary trait. The fight or flight response is an ancient emotional response and must be deeply rooted in our neural network, even the simplest organisms react to outside stimulus.

Unfortunately, as far as I know, there is not a large body of research as yet. I look forward to a real map of the brain and how it communicates with itself and the rest of the body.

I am also intrigued by the possibility that we formulate internal holograms from visual and other sensory stimulation. IMO, it is essential in forming 3D images in our mind.

Striding into a conversation without actually knowing how to answer the question seen... does not disqualify my opinion..
~ We learn to learn and we yearn to know that which we do not. The human brain is well understood to be complex.
Very complex and I have no idea how a memory is actually held. Neural pathways and connections and synopsis and chemical changes with micro electric cell signals.. all are terms herd used and not understood by me. Yet I also see a volley of opinion discussing the human soul and argue that no proof of such is found as real.. How does the mind work and what is a memory.. That I can remember a dream as if were real when knowledge tells me, no.. If you get a answer for this I want to know it.. Mark.. or ask Roberttybob..

Originally Posted by astromark

Striding into a conversation without actually knowing how to answer the question seen... does not disqualify my opinion..
~ We learn to learn and we yearn to know that which we do not. The human brain is well understood to be complex.
Very complex and I have no idea how a memory is actually held. Neural pathways and connections and synapses and chemical changes with micro electric cell signals.. all are terms heard used and not understood by me. Yet I also see a volley of opinion discussing the human soul and argue that no proof of such is found as real.. How does the mind work and what is a memory.. That I can remember a dream as if were real when knowledge tells me, no.. If you get a answer for this I want to know it.. Mark.. or ask Roberttybob..

I have little formal education but I do read a great deal. So I always try to qualify my observations as probative or as an intuitive opinion. I hope that even in a reputable Science Forum as this, some speculation is allowable if it is based on accepted knowledge. I never formally propose a NEW hypothesis. I know my limitations.

OTOH, if a computer has the ability to store and recall "sensory" information in a variety of ways including 3D colored images and sounds from music to languages, I see no reason why the human brain would not be able to do this very efficiently. We've been at this much longer than computers.

This research was done on monkeys.

Abstract

Neurophysiology reveals the properties of individual mirror neurons in the macaque while brain imaging reveals the presence of ‘mirror systems’ (not individual neurons) in the human. Current conceptual models attribute high level functions such as action understanding, imitation, and language to mirror neurons. However, only the first of these three functions is well-developed in monkeys. We thus distinguish current opinions (conceptual models) on mirror neuron function from more detailed computational models. We assess the strengths and weaknesses of current computational models in addressing the data and speculations on mirror neurons (macaque) and mirror systems (human). In particular, our mirror neuron system (MNS), mental state inference (MSI) and modular selection and identification for control (MOSAIC) models are analyzed in more detail. Conceptual models often overlook the computational requirements for posited functions, while too many computational models adopt the erroneous hypothesis that mirror neurons are interchangeable with imitation ability. Our meta-analysis underlines the gap between conceptual and computational models and points out the research effort required from both sides to reduce this gap.

Mirror neurons and imitation: A computationally guided review

As a gross oversimplification for the purposes of illustration - taking neurons that encode numbers, neurons that encode names and neurons that encode dates. When the sentence has been read the neurons will fire together and make a circuit - normally in learning repeated firings strengthens the circuit but when something is sufficiently salient in the environment the circuit can be strong first time round. In your example, reading that 2+2=5 might be sufficiently strong to form a lasting circuit because it would be surprising and unusual the first time it was seen. Once the circuit has been established it has the potential to be activated any time you encounter the name or the equation or the date.

So the synapse doesnt represent a number but neurons do.

Hi Luci, I'm guessing that taking away the oversimplification, means that instead of thinking of objects/numbers as attached to a neuron, it would be contained in a smaller physical feature. I suppose an object would be represented by a unique firing pattern, between unique synapses, that are completely unique to that person. Except in a hierarchical manner, so that from very small physical features such as lines, that are represented by lower-order neuronal firing, you end up with a circuit and firing pattern that represents that object.

Originally Posted by LuciDreaming

As a gross oversimplification for the purposes of illustration - taking neurons that encode numbers, neurons that encode names and neurons that encode dates. When the sentence has been read the neurons will fire together and make a circuit - normally in learning repeated firings strengthens the circuit but when something is sufficiently salient in the environment the circuit can be strong first time round. In your example, reading that 2+2=5 might be sufficiently strong to form a lasting circuit because it would be surprising and unusual the first time it was seen. Once the circuit has been established it has the potential to be activated any time you encounter the name or the equation or the date.

So the synapse doesnt represent a number but neurons do.

Can those specialized circuit be called mirror neural networks? They seem to invoke the same emotional and physical response every time thereafter.

And is it possible our 3D perception and memory are vast domelike shaped neural networks, the holograph within? I find it remarkable that we can experience great panoramas inside our head. How do we manage enough room? Just musing.

Perhaps we compensate by narrowing our focus and interpretive processes. IMO, optical illusions are mental attempts to create order from memory when exposed to extraordinary sensory input data.

These may be fun and interesting,
The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us
Adelson's Checker-shadow illusion

How does anyone fail to spot that gorilla? Okay I knew about this from reading Richard Dawkins and how he failed to spot it. But I hadn't seen this video before.

Originally Posted by Curiosity

Hi Luci, I'm guessing that taking away the oversimplification, means that instead of thinking of objects/numbers as attached to a neuron, it would be contained in a smaller physical feature. I suppose an object would be represented by a unique firing pattern, between unique synapses, that are completely unique to that person. Except in a hierarchical manner, so that from very small physical features such as lines, that are represented by lower-order neuronal firing, you end up with a circuit and firing pattern that represents that object.

Numbers are actually represented by clusters of neurons although its not 1 neuron = 1 number. Thats the reason its harder to differentiate between 5 and 6 than it is to differentiate between 5 and 9 because 5 and 6 will be represented by the same neuron (thats just an example). There is some evidence to suggest that some things are represented by individual neurons or clusters of specific neurons for example some people after strokes are unable to name man made objects but have no problem with natural ones, some people lose verbs but not any other part of speech. I think its generally safe to say that objects are attached to (encoded by) neurons and memories are the circuits that link the neurons together.

I have to say my understanding of mirror neurons is that they are involved in social interaction allowing us to understand the actions of others and form the basis of 'theory of mind' - the process which allows me to understand that others have a different view of the world to myself. But my knowledge of them is limited to that.

I love the gorilla skit - most people see it as demonstrating the limitations of the brain - I see it as testament to the incredible power of focussed attention which allows us to mentally block out everything else that is going on in the world in order to focus specifically on one thing. And this is no mean feat in a central nervous system that exists only to pick out sensory information in the environment.

Originally Posted by ox

How does anyone fail to spot that gorilla? Okay I knew about this from reading Richard Dawkins and how he failed to spot it. But I hadn't seen this video before.

ok, but did you get the count correct?

I got so excited when I saw this thread. Radiolab do an awesome podcast on this very thing. If you have a spare hour or so, it's very comprehensive, layman-friendly and very well worth the listen.!

Memory and Forgetting - Radiolab