[HN Gopher] An aberrant precision account of autism (2014)
___________________________________________________________________
An aberrant precision account of autism (2014)
Author : danboarder
Score : 36 points
Date : 2022-04-25 15:01 UTC (2 days ago)
(HTM) web link (www.frontiersin.org)
(TXT) w3m dump (www.frontiersin.org)
| gowld wrote:
| Is there a simple English version of this?
|
| "aberrant precision" is in't even defined specifically precisely
| defined, ironically.
| munificent wrote:
| Here's an attempt with the caveat that I'm not at all an expert
| on this and may get lots of things wrong:
|
| The basic idea is that there is a world "out there", and then
| each person has a mental model of that world. Our actions are
| not based on the external world, but on our internal model of
| it.
|
| When sensory information comes in, we use that to update the
| model. The loop is something like:
|
| 1. Stimulus comes in.
|
| 2. Figure out what that means.
|
| 3. Use that to update the model.
|
| 4. Take action based on that.
|
| 5. See how our action affected the world and goto 1.
|
| Step 2 is the tricky one. Stimulus is often ambiguous and our
| perceptions of it are imperfect. You see a flash of light. It
| could mean someone took a photo, the sun glinted off a moving
| object, or maybe just a spurious firing on our optical nerve.
| How do we know how to update the model based on that stimulus?
|
| We can't just always assume the stimulus is fully accurate and
| blanket update the model based on it because there's a lot of
| noise in the data. We also can't just assume that whenever the
| stimulus disagrees with the model that it's noise and discard
| it. The _whole point_ of perception is to update our model to
| reflect a changing world.
|
| So we have to decide _what_ a piece of stimulus means (since it
| 's ambiguous) and _how much confidence_ we have in that
| interpretation (since it 's noisy). How might we decide a
| confidence level? All we know is our own model and that the
| external stimulus.
|
| There are a bunch of different ways that involve things like
| estimating how likely a stimulus like that is to occur, our
| previous experience with misinterpreted signals (i.e. what we
| have learned about our own perceptual hardware), etc.
|
| Of course, none of this is happening consciously. It's _how_
| the brain itself thinks.
|
| The thesis of the article is that those with autism have this
| process miscalibrated where they treat external stimulus as
| much more precise (i.e. less noisy or ambiguous) than it
| actually is. The symptoms of autism are then emergent phenomena
| of how a brain might try to cope with that problem.
| zozbot234 wrote:
| Very nice paper! For useful background on neural prediction, see
| "The brain is a Peirce engine" - http://esr.ibiblio.org/?p=7651
| pedro2 wrote:
| Oh, an ESR follower. Kinda curious about how he is after the
| pandemic.
| Qem wrote:
| I was curious too. he used to post regularly in his blog, but
| then he stopped in september 2020 and didn't write since
| then. I liked his nice technical posts, albeit they were
| intermingled with some occasional gun nut stuff.
| bitwize wrote:
| He tried to fix the database bug that has been plaguing his
| blog late last year. He appeared to be making some
| progress, but it reasserted itself.
|
| He's in his late 60s now, his brain probably hasn't as much
| processing power as it used to, and I think faffing about
| with Linux and all the moving parts that make up a self-
| maintained blog is becoming just as baffling and tiresome
| to him as it is to nearly everyone else.
| xpuente wrote:
| One might wonder how Predictive Processing/Coding works when the
| "cortex" is empty (i.e., at birth). I don't know if this is just
| armchair neuroscience wrapped in a bunch of mathematical
| flourishes.
| MarkusQ wrote:
| The cortex is never "empty". The blank slate model is an
| outdated speculation with no empirical support, akin to "you
| only use 10% of your brain" or "you can tell things about
| people's personality by feeling the bumps on their head".
| xpuente wrote:
| I'm not sure that there is no empirical support: see [0]
|
| [0] A. Roe, S. Pallas, Y. Kwon, and M. Sur, "Visual
| projections routed to the auditory pathway in ferrets:
| receptive fields of visual neurons in primary auditory
| cortex," J. Neurosci., vol. 12, no. 9, pp. 3651-3664, Sep.
| 1992.
|
| PS: I'm not saying that there is uniform initial
| connectivity. Just, the prediction level units (cortical
| columns) are unable to predict anything until they learn
| "something".
| MarkusQ wrote:
| As that paper's abstract says, "Cells in A1 of rewired
| animals differed from cells in normal V1: they exhibited
| larger receptive field sizes and poorer visual
| responsivity, and responded with longer latencies to
| electrical stimulation of their inputs" -- that is, the
| aditory cortex expects auditory data, and although it can
| adapt it doesn't handle it as effectively as the visual
| cortex does, because it's expectations aren't met. So
| that's evidence that there are predictions baked in from
| day one.
| [deleted]
| jedimastert wrote:
| Oh this is gonna be a fun deep dive, although a lot has changed
| around autism, even over the last 7 years or so.
___________________________________________________________________
(page generated 2022-04-27 23:02 UTC)