23 replies to this topic

[ParanoiA]

Not sure how to ask this question...is there a particular area or section of the brain responsible for imagination? Daydreaming? Story-telling?

I was hoping this was restricted to one particular area, one label, but I have a feeling it draws on multiple areas.

[iNow]

I was hoping this was restricted to one particular area, one label, but I have a feeling it draws on multiple areas.

Your feeling is the right one. It involves all of the different regions, much like dreaming. Here's the kicker, though... the different regions which are involved depend greatly on the subject of your imagination.

For example, if you are imagining a big math problem, it would be prefrontal cortex. If you were imagining pitching a fast ball during the world series, your motor cortex would be more involved. If you were imagining a painting of clouds, it would be more the occipital cortex.

Then, on top of all THAT, there are the contributions from your more basic reptilian brain regions, the emotional and memory areas, like the hippocampus and amygdala, which change the "taste" or "texture" of those imaginative explorations.

Glider is the best person here to answer such questions, but you'd probably need to be a bit more specific first ("When I imagine X, and how it relates to Y, which brain regions tend to show the most activity on fMRI scans or PET...positronic emission topography... or CAT scans?)

Interesting question, though. Now you've got me thinking about this.

[ParanoiA]

Cool. Alright, well let me elaborate then. The subject of my imagination, in this context, is music. The different areas that contribute are interesting, but is there one that stands out, or contributes the most perhaps?

[bascule]

The neocortex and thalamus are the two primary areas involved in consciousness, creativity, imagination, etc.

[iNow]

Cool. Alright, well let me elaborate then. The subject of my imagination, in this context, is music. The different areas that contribute are interesting, but is there one that stands out, or contributes the most perhaps?

Then, in addition to the parts bascule referenced, you'd also see higher levels of activation in the auditory cortex:

http://en.wikipedia....auditory_cortex



Btw - the thalamus is like a crossroads or a junction through which almost all neural signals travel. "All roads lead to the thalamus."

[ParanoiA]

Great stuff. Thanks guys. It gave me an idea too. I was working on this tune that has a "live" feel, so I added some crowd noise and stuff to make it sound like a live performance. I think I'm going to call it Live at the Thalamus, since it's not really live but rather all in my head.

So, double thanks.

[iNow]

Very nice.

[YT2095]

IIRC, the Right hemisphere deals with imaginative aspects, and the left is mostly the Logical side.

[Glider]

In addition to the above by iNow and bascule, there would also be activity in your hippocampus and areas in your medial temporal lobes (associated with memory).

Dreams are not direct experiences, but elements from memory, reintegrated in higher areas of the cortex, particularly the frontal and prefrontal areas as that's where we hold our personal models of 'reality'.

There is unlikely to be much activity in the occipital lobes as these are the primary visual cortices and respond directly to stimulation from the retinae (which is unlikely when you're asleep). Stimulation of the primary visual cortex only produces very basic events; e.g. flashes of light. However, there would be more activity in secondary visual areas in the temporal lobes as these are responsible for more complex patterns, shapes and images.

The images you see in dreams are based on (reconstructed from) memories and so would most likely be the products of activity in memory areas (hippocampus - medial temporal areas) and higher visual centres (temporal lobes) being reintegrated in higher association areas in the cortex. Auditory centres are also in the temporal lobes and so for music, I would expect a similar interaction.

iNow is quite right in that the particular areas of activity would correspond to the type of experience. The only caveat would be that primary areas (i.e. those dealing with direct sensory input from the thalamus) are not likely to be involved. It's more likely to be higher areas (responsible for sensory integration) and memory areas. The exception is primary motor areas. These are active in REM sleep, which is why REM atonia (a kind of paralysis that happens during REM sleep) happens, to stop us acting out our dreams.

[ParanoiA]

Interesting. So, if I understand correctly, imagining music, like playing a song in my head, doesn't necessarily impact my Primary Auditory Cortex right? Because I'm not actually processing sensory input? More of a temporal activity I guess. I suppose the thalamus is still central though...? iNow said most roads lead to the thalamus, so I'm not sure if that includes just imagining or day dreaming, or if it requires sensory input.

By the way, thanks everybody.

[iNow]

One thing I gleaned from Gliders post is that the thalamus has more to do with actual sensory input (physically being touched or actually receiving sound in the ear canal), so I'm led to believe that (in the case of dreams and imagination) the thalamus is not really a factor (or, at least not a major one).

Also, the auditory cortex is in the temporal lobe, along with the secondary visual areas, so would VERY MUCH be involved. It is tied closely to the areas in that same region of the brain (temporal lobe) which is involved in memory. So, the temporal lobe seems to be the biggest player for these types of experiences, so long as you remain aware of the memory implications and impact from the hippocampus.

So, maybe you can alter the title to "Live at the Brodmann" (see wiki link in primary auditory cortex for clarification).


However, what I'm not sure about is whether or not it's the primary auditory cortex which is more important here, or the secondary/teritiary (see Gliders comments on primary visual cortex, and how most processing goes on in secondary and tertiary areas).



From the wiki on Primary Auditory Cortex link shared above:

The secondary auditory cortex has been indicated in the processing of “harmonic, melodic and rhythmic patterns.” The tertiary auditory cortex supposedly integrates everything into the overall experience of music.

[ParanoiA]

Damn iNow, that's very cool. (Brodmann works so much better for my purposes too since it doesn't give itself away unless a person has been exposed to the subject).

I took this...

iNow is quite right in that the particular areas of activity would correspond to the type of experience. The only caveat would be that primary areas (i.e. those dealing with direct sensory input from the thalamus) are not likely to be involved.

...to mean that the Primary Auditory Cortex would deal with direct sensory input and might not be involved, but secondary, tertiary may be - and from that wiki link, it definitely seems to be the case. I don't know, I'm definitely not in my comfort zone here. That's really interesting. Secondary handling the patterns while the tertiary puts it all together, sort of.

I was getting kind of attached to the Thalamus, though.

[Glider]

It's a nice little thing to get attached to. I'm quite attached to mine also, but as far as sensory input goes, it's really just a very complex relay station. All sensory input goes to the thalamus (except smell), and it's routed from there to appropriate primary cortical areas.

The primary sense areas integrate the signals and attach the most basic labels. Remember, all the 'signals' are just action potentials, regardless of the sense involved. The primary areas attach the basic labels 'sound' and 'light' and sort differences in frequency into quiet/loud, dim/bright and input form different cells is labelled (e.g. into red, green and blue, none of which actually exist outside of our brains).

As the information progresses in (e.g.) the visual system, it passes through layers of cells, each responding to differences in qualities of the signals. There are cells that respond to vertical bars/edges. horizontal bars/edges and so-on. These signals are combined and the further into the system you go, the more complex the signal becomes as more information is integrated.

There are cells that respond to specific combinations of bars/edges. In humans and primates there are single cells that respond to faces, which are quite complext patterns of edges, lines etc. This is why the smiley badge works; it triggers those cells.

Dreams work backwards. There is no primary sensory input and the drive is from memory. Memory is reconstructive and so it takes higher elements and reintegrates them. This would require activity in the higher sensory areas, but not the primary areas.

So, you would have activity originating in areas associated with memory (limbic areas), elements of memory being reintegrated in the higher sensory areas appropriate to the sense and then reintegrated information being pushed to higher association areas of the cortext for final integration into a working model (dream) in the prefrontal and frontal areas.

'Live at the limbic' would be cool.

[ParanoiA]

That's fascinating. I'm probably simplifying too much, but it makes some sort of sense to me that secondary and tertiary auditory systems be engaged when drawing from memory - no sensory input, just pure imagination. Conceptually, I'm assocating the primary auditory cortex to be the "interface", if you will, to external sources of sound, while the secondary and tertiary (and higher orders I'm guessing?) process that sound. So then it would make sense that drawing from imagination would still require the higher sensory areas, since it still needs the sounds to be processed, only from an internal source, the memory.

But, how does memory get accessed if the thought is new? I'm not clear on that. Unless of course the term "memory" carries implications that aren't accurate, it would appear that memory would require some previous input. But if I'm sitting here creating a song in my head, where would the "source" be in that case?

I like Live at the Limbic. But I also like Live at the Brodmann. Decisions, decisions...hmmm.

[iNow]

You could go with "Banned from the Brodmann" if it doesn't come out how you intend.

Memory is a complex place. It's not all about showing snapshots of the past, but instead a complex interplay of sensations, feelings, desires, and they way they all come together is not always so straight forward.

We live our day, and experience all sorts of different things. That data is organized by organic connections which are constantly making new neural (synaptic) junctions and trimming old ones. It's during this trimming and organizing process that things get really interesting.

Something doesn't have to come from our past in order to activate the memory systems. There's also this thing known as false memory, where we literally remember something that never happened, or change the details/fill in the gaps with a story line that never took place.

The mind is a wonderous and strange place, my friend. It's not a single "note" here or there which makes its music. It's the entire symphony and all of the different pieces taken together which paint the rich tapestry of our worlds.

[ParanoiA]

You two have really provoked a lot of thought in my particular noggin, that's for sure. The way you two describe this is so much more interesting than reading it on wikipedia - I keep yawning and losing interest after two paragraphs on there.

[foodchain]

I always got confused with the working application of the word somatic with such issues. Could you say that somaticlly the brain interacts with its surroundings?

[iNow]

I'm not sure that makes a lot of sense. The word "somatic" comes from the root "soma," which means "body," usually in the sense of a cell body in the nerves.

Somatic just means "pertaining or relating to the body."

There is also "psychosomatic," wherein the brain causes a physical ailment. Stuff like obsessing about a rash on your skin, and then it gets worse. Your thoughts can literally kill you... psychosomatically.


Maybe that helps provide some context. It's been more than a decade since I studied this stuff so I'm uber-rusty.

[Glider]

But, how does memory get accessed if the thought is new? I'm not clear on that. Unless of course the term "memory" carries implications that aren't accurate, it would appear that memory would require some previous input. But if I'm sitting here creating a song in my head, where would the "source" be in that case?

It's because there really isn't such a thing as a 'new' thought.

You were talking about imagining music originally. I've been playing Rodrigo's Concierto De Aranjuez in my head for the last couple of days (can't seem to get rid of it). I can do a number of things with it in my mind; I can swap the lead from oboe to guitar to flugel horn. I can even swap it to harp if I try, but I can't swap it for something I've never heard before. I can vary the melody in my mind, shift it from minor to major and even change the order of the notes, but I can't reproduce notes I've never heard. These are all variations on a theme.

Composers can create new music, but this is just novel variations of sounds they already have in their memories.

Look at all the different houses in your city, all the different styles of architecture, different shapes, sizes colours, numbers of rooms, arrangements of rooms and so-on, but they're all made of bricks and timber, just in different arrangements.

It's like that old thought experiment; try to create in your mind a completely new animal. Whatever you do, it's going to end up a mixture of elements you already have in your memory. Will it have scales, skin, fur, feathers or a shell? You already have these elements. What else could it have? Legs, wings, claws or paws? Again, recycling stuff that already exists.

I like Live at the Limbic. But I also like Live at the Brodmann. Decisions, decisions...hmmm.

It's a toughy for sure.

Edited by Glider, 7 December 2008 - 09:43 AM.

[foodchain]

It's because there really isn't such a thing as a 'new' thought.

You were talking about imagining music originally. I've been playing Rodrigo's Concierto De Aranjuez in my head for the last couple of days (can't seem to get rid of it). I can do a number of things with it in my mind; I can swap the lead from oboe to guitar to flugel horn. I can even swap it to harp if I try, but I can't swap it for something I've never heard before. I can vary the melody in my mind, shift it from minor to major and even change the order of the notes, but I can't reproduce notes I've never heard. These are all variations on a theme.

Composers can create new music, but this is just novel variations of sounds they already have in their memories.

Look at all the different houses in your city, all the different styles of architecture, different shapes, sizes colours, numbers of rooms, arrangements of rooms and so-on, but they're all made of bricks and timber, just in different arrangements.

It's like that old thought experiment; try to create in your mind a completely new animal. Whatever you do, it's going to end up a mixture of elements you already have in your memory. Will it have scales, skin, fur, feathers or a shell? You already have these elements. What else could it have? Legs, wings, claws or paws? Again, recycling stuff that already exists.

It's a toughy for sure.

I can remember songs rather well, not as in play them but just how they sound. To add to this at times, when near to sleep only, I can imagine music that I have never heard before. I don't kwow if the sounds themselves are new to me, just them together in a song. I do not think all of these sounds I have heard before, because I can not recall music or sound terrifically well, as in to verbalize it. Lastly when I become aware of this, any thinking about it in particular on my part destroys it.