interesting theory on the basis of hypersensitivity

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jbw
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28 Jun 2014, 6:12 am

http://www.sciencedaily.com/releases/20 ... 131957.htm

Typically, our response to a stimulus is reduced over time if we are repeatedly exposed to it. This process of habituation enables organisms to identify and selectively ignore irrelevant, familiar objects and events that they encounter again and again. Habituation therefore allows the brain to selectively engage with new stimuli, or those that it 'knows' to be relevant. For example, the unusual sensation created by a spider walking over our skin should elicit an appropriate evasive response, but the touch of a shirt or blouse on the same skin should be functionally ignored by the nervous system. If habituation does not occur, then such unimportant stimuli become distracting, which means that complex environments can become overwhelming.

Habituation has long been recognised as the most fundamental form of learning, but it has never been satisfactorily explained. ..., Mani Ramaswami, explains habituation through what he terms the 'negative-image model.' The model proposes and explains how a repeated activation of any group of neurons that respond to a given stimulus results in the build-up of 'negative activation', which inhibits responses from this same group of cells.

A process of negative activation to counteract intensive sensory input in a typical brain is a plausible explanation for the construction of powerful cognitive filters. Such filters may make a high volume of raw sensory input much more tolerable. At a higher level of cognitive processing, they may also allow the subconscious interpretation of facial expressions in terms of simple categories of emotions etc.

If such filters are lacking, the autistic brain may either resort to conscious processing and interpretation of input, resulting in delayed reactions due to level of cognitive load, or resulting in overload if the input is too intense.

For example, the first view of an unfamiliar and scary face can trigger a fearful response. However after multiple exposures, the group of neurons activated by the face is less effective at activating fear centres because of increased inhibition on this same group of neurons. Significantly, a strong response to new faces persists for much longer in people on the autism spectrum. This matched increase in inhibition (the 'negative image'), proposed to underlie habituation, is not normally consciously perceived but it can be revealed under particular conditions.

From my perspective this explanation makes a lot of sense. It has the potential to explain why autistics consciously notice many details that typically get filtered out at a subconscious level, thereby avoiding sensory overload. I also like that this theory does not claim that autistics don't react to faces, but can actually react rather strongly depending on the situation.

I always thought that I perceive patterns that others don't seem to notice, even when presented with the same input. The lack of habituation and the conscious processing of details has obvious benefits in any analytical or experimental scientific context.

This research underscores that rather than attempting to change or train the autistic brain, the best approach to avoiding negative symptoms is to either modify the environment, which may include avoiding social interaction, or to use tools that filter and reduce sensory inputs when needed.

What are your thoughts?



Last edited by jbw on 28 Jun 2014, 8:42 am, edited 2 times in total.

BeggingTurtle
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28 Jun 2014, 6:27 am

Science language. All I'm going to say is my touch is mine alone.


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kaedatiger
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28 Jun 2014, 8:25 am

This is interesting to think about. I wonder if it means there's a direct connection between my capacity for sensory overload and my quick learning speed.



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28 Jun 2014, 9:00 am

jbw wrote:
http://www.sciencedaily.com/releases/2014/06/140618131957.htm

Typically, our response to a stimulus is reduced over time if we are repeatedly exposed to it. This process of habituation enables organisms to identify and selectively ignore irrelevant, familiar objects and events that they encounter again and again. Habituation therefore allows the brain to selectively engage with new stimuli, or those that it 'knows' to be relevant. For example, the unusual sensation created by a spider walking over our skin should elicit an appropriate evasive response, but the touch of a shirt or blouse on the same skin should be functionally ignored by the nervous system. If habituation does not occur, then such unimportant stimuli become distracting, which means that complex environments can become overwhelming.

Habituation has long been recognised as the most fundamental form of learning, but it has never been satisfactorily explained. ..., Mani Ramaswami, explains habituation through what he terms the 'negative-image model.' The model proposes and explains how a repeated activation of any group of neurons that respond to a given stimulus results in the build-up of 'negative activation', which inhibits responses from this same group of cells.

A process of negative activation to counteract intensive sensory input in a typical brain is a plausible explanation for the construction of powerful cognitive filters. Such filters may make a high volume of raw sensory input much more tolerable. At a higher level of cognitive processing, they may also allow the subconscious interpretation of facial expressions in terms of simple categories of emotions etc.

If such filters are lacking, the autistic brain may either resort to conscious processing and interpretation of input, resulting in delayed reactions due to level of cognitive load, or resulting in overload if the input is too intense.

For example, the first view of an unfamiliar and scary face can trigger a fearful response. However after multiple exposures, the group of neurons activated by the face is less effective at activating fear centres because of increased inhibition on this same group of neurons. Significantly, a strong response to new faces persists for much longer in people on the autism spectrum. This matched increase in inhibition (the 'negative image'), proposed to underlie habituation, is not normally consciously perceived but it can be revealed under particular conditions.

From my perspective this explanation makes a lot of sense. It has the potential to explain why autistics consciously notice many details that typically get filtered out at a subconscious level, thereby avoiding sensory overload. I also like that this theory does not claim that autistics don't react to faces, but can actually react rather strongly depending on the situation.

I always thought that I perceive patterns that others don't seem to notice, even when presented with the same input. The lack of habituation and the conscious processing of details has obvious benefits in any analytical or experimental scientific context.

This research underscores that rather than attempting to change or train the autistic brain, the best approach to avoiding negative symptoms is to either modify the environment, which may include avoiding social interaction, or to use tools that filter and reduce sensory inputs when needed.

What are your thoughts?

For a very long time, I also believed that a' faulty cognitive filter mechanism' was the cause of my/others hypersensitivity, but after deep meditation on the issue, I now believe that the cause is more organic than a mere exercise in habituation or any behavioural or cognitive process.

After my bout of shingles (herpes), I suffered with hyper-hyper sensitivity and could 'feel' things happening that simply......weren't happening at all (neuralgia).

My nerve-endings were 'raw' as it was and they were 'feeling' phantom feelings....like the feelings an amputee still experiences in an amputated limb..like having a toothache in a tooth that has been extracted...like how Krilian Photography photographs the 'energy' of a full leaf after that leaf has been torn in half....the whole 'over sensitivity' thing has something to do with this...exactly what it has to do with it, well that part of it hasn't quite been 'revealed' to me yet. ;)

All I know is that it has to do with the (lack) of certain neurochemical transmitter substances...I'm taking it more biochemical.



Ettina
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28 Jun 2014, 11:50 am

Yeah, lack of habituation definitely contributes to sensory hypersensitivity.



foodeater
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29 Jun 2014, 3:06 pm

yeah, i was thinking along those lines too.

my thinking was that the ASD brain maybe uses the conscious brain to process information that is typically unconscious that other people get to choose more when to think about it- and that part of the overwhelm happens because all that subconscious stuff is things that people have no words or imagery for naturally. so it can be like noise or leads to synesthesia.

i was thinking about how animals that have no conscious processing, as far as we know, are still able to be highly social. because with social stuff, i don't think i'm totally unaware, i just can't go on "autopilot" and process multiple streams at once. i'm more thinking about what i'm doing and how i'm interacting or about what other people are doing as separate and distinct events.

it's part of why i thought meditation is helpful for me and i seem to have an easier time than the average person getting into it because meditation helps slow down and order stuff that was already going through my conscious mind, while with other people meditation is perhaps exposing them to stuff that they've never had to process before.

i think my "intuition training" by working on creative processes and not judging has been very helpful - it's like working to direct hyper focus. i think i probably get more "enjoyment" out of it than is typical because it's effective in blocking out a lot of the "noise" so the reward response provides positive feedback to continue with it.

i think hyper focus is kind of a misleading term because that seems to imply greater focus, when for me at least, it's really more a state of not focusing. the term "focus" itself is sort of a visual metaphor where it's like you're choosing to look more closely, subject, object verb, style, but i find it more like i'm immersed and my sense of self disappears. there's no distinction between me, the activity i'm doing and what i'm interacting with.

i dunno how much is ASD and just me though. :) i know a lot of people say they value logic. i find while it has it's uses it feels more restrictive to be in that mode all the time and is largely something i have to do to manage processing. to me logical processing is more what i would call hyper focus, because i feel more separation between myself and my thoughts as i'm breaking things down into smaller details and taking them one after the other, like going through a movie frame by frame. but reality is more like tree branches or roots. by thinking in a linear manner like that i find i skip over all those branches. or it's kind of like being in a train on switching tracks without having a destination or map and as a each switch comes up you make a decision. all those other routes have to be ignored to get to a single destination or else you'd be traveling around forever. it doesn't mean it's the right (or wrong) destination, it's just where i ended up. :) when i work with intuition i can jump around instantly and check things out without having to travel to get there. i feel better when it's safe to be in either mode roughly an equal amount.