Understanding Predictive Coding in the Brain
In PlainSpeak for the Lay Reader
Researchers have come up with many theories to try to explain different aspects of thinking and behavior in autism. The Predictive Coding Hypothesis is one such set of explanations.
Understanding Predictive Coding in the Brain
This hypothesis says that the brain acts like a prediction machine, always guessing what's going to happen based on past experiences. For example, if you hear a familiar sound, like a door creaking, your brain might predict that someone is entering the room. When something happens, the brain compares it to what it expected and updates its guesses to be more accurate next time.
Predictive Coding in Autism
Scientists think that the brains of autistic people might process these predictions differently. This could explain some common characteristics of autism, like sensory sensitivities, repetitive behaviors, and social challenges.
Slow Updating Theories
What This Means: Autistic people might update their brain’s predictions more slowly. This means their brain doesn’t adjust as quickly when something new or unexpected happens.
Possible Effects:
- Repetitive Behaviors: They might rely more on routines or repetitive actions to cope with the world because it feels more predictable and safe.
- Sensory Sensitivities: Because their brain takes longer to adjust, unexpected noises, lights, or touches might feel very intense or overwhelming.
- Social Challenges: Social interactions often require quick thinking and adapting, so slow updating might make it harder to understand and react to what others are doing or saying.
Examples of Slow Updating Theories:
- Predictive Coding Deficit Theory: Autistic people may have a harder time updating their brain’s predictions with new information, which can make adjusting to changes difficult.
- Reduced Sensory Prediction Error Theory: The brain might not be good at noticing when it made a wrong prediction, leading to slower updates and more intense sensory experiences.
High-Precision Theories
What This Means: Autistic people might focus too much on the details of what they sense, giving a lot of importance to every little thing they see, hear, or feel.
Possible Effects:
- Sensory Overload: Because they notice so many details, it can become overwhelming and lead to sensory overload.
- Literal Thinking: They might take things very literally and have trouble understanding implied meanings or jokes.
- Detail-Oriented: They might focus a lot on small details but find it hard to see the bigger picture.
Examples of High-Precision Theories:
- Aberrant Precision of Prediction Errors: Autistic people might give too much importance to their senses, leading to strong reactions to things like noise or bright lights.
- Increased Sensory Precision Theory: Their brain treats all sensory input as very important, making it hard to ignore unimportant details.
- Attenuated Priors Hypothesis: Their brain’s expectations (or “priors”) are weaker, so they rely more on the immediate sensory input, giving it more weight.
Other Theories in Autism
Aberrant Salience Theory: Autistic people might over- or under-estimate the importance of certain things they sense, which can make it hard to focus on what really matters.
Precision of Priors and Prediction Errors: There might be an imbalance in how the brain handles predictions and errors. This could lead to rigid behaviors or heightened sensory responses.
Adaptive Coding Hypothesis: The brain of an autistic person might be tuned differently, focusing on details that others might not notice. This could explain both their strengths, like noticing small details, and challenges, like understanding social cues.
Enhanced Perceptual Functioning Model: Autistic people might be really good at noticing small details but might struggle to see the bigger picture.
Predictive Homeostasis Theory: Autistic people might aim to keep their brain in a balanced state, which could explain why they prefer routines and predictability.
Intense World Theory: The brain of an autistic person might be hyper-sensitive, making the world feel very intense. This might lead to sensory overload and a preference for predictable environments.
Combining Theories
These different theories aren’t mutually exclusive; they can coexist in the same person. For example, someone might experience both slow updating and high precision, leading to a mix of challenges, like sensory overload and a need for routines.
Autism and Abstract Thinking
There’s a stereotype that autistic people can’t think abstractly or see the big picture. This isn’t true for everyone. While some autistic individuals might focus on details, many also excel in areas that require abstract thinking, like art, poetry, and storytelling. These creative activities often involve both concrete details and abstract ideas, showing the diverse cognitive strengths within the autistic community.
Final Thoughts
Understanding how autistic people think and process information is complex, and these theories help provide some explanations. However, it’s important to remember that every autistic person is different, and more research is needed to better understand and support them. There’s no one-size-fits-all approach to autism, and each person’s unique experience should be respected.
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For the Scientific/Academic Audience
Cognitive dissonance on ADOS
But disappointed at a few things that caused a lot of cognitive dissonance for me.
Video of kid who repeated back 2-3 words of one question of the clinician before responding - behavior marked as “echolalia”. But NT folks do this all the time, eg: common tactic in interviews as it buys you time to think. In the NT world this is called "active listening" Yet given as a negative label of echolalia in an autistic child instead of useful social strategy.
"Severe autism has reduced in the last 40 years." Not accurate!! It's just that autism includes many other dx since DSM-V and expanded to accommodate all ages, resulting in a bigger pool, so obviously that %severe looks smaller.
The type of ADOS module used depends on the oral level of the child. Module 1 is the one used for non-verbal/ minimally verbal kids. Seemed to imply that oral communication mandatory for ADOS, cannot be coded if child uses AAC.
Justification given is that use of AAC means
- "It changes nature of eye contact."
- "Are they modulating eye contact in some way"
- "It changes the nature of what is happening."
- They are not making eye contact when they are looking at device.
- They are not doing social engagement with you while looking at device
- There may be some pre-made phrases on device they are making use of
So my question was whether ADOS then is not applicable to the 20-30% of autistics who have no to little spoken language.
Apparently ‘gestures’ are allowed but how much can you communicate with gestures unless you are fluent with ASL. And it is likely that kids with oral communication issues usually also have motor apraxia so their gesturing ability will not good as well.
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Keynote at Duke ACE on Apr 3.
We are thrilled that Hari Srinivasan will deliver the keynote for our #AutismAcceptance Month Event, Wed, Apr 3 at 4pm EST. Hari Srinivasan is a self-advocate, neuroscience PhD student and @PDSoros Fellow at Vanderbilt, & ACE committee member. Register at
What is LTP and LTD and how do they relate to Autism?
PlainSpeak. In Plain Language for the Lay Reader
Our brain cells (neurons) connect with each other through synapses, which are like tiny bridges for communication. These connections can change in strength, helping us learn and remember. Two key ways these connections change are Long-Term Potentiation (LTP) and Long-Term Depression (LTD).
- LTP: This is when the connection between two neurons gets stronger. Think of it like a friendship that grows stronger the more you interact.
- LTD: This is when the connection weakens, similar to a friendship that fades when you stop interacting.
Hebbian Plasticity
Hebbian plasticity is a rule that explains how these changes happen: "cells that fire together, wire together." This means that if two neurons are active at the same time, their connection strengthens (LTP). If one neuron is active while the other is not, their connection weakens (LTD).
How LTP and LTD are Different in Autism
Research has shown that people with autism often have differences in how LTP and LTD work, which can affect learning and behavior:
Memory and Learning:
Movement and Coordination:
- The cerebellum, which helps control movement, shows problems with LTD in autism. This can lead to issues with coordination and motor skills (Fatemi et al., 2012) (Nature).
Genes and Synapses:
- Certain genes that help keep synapses strong and flexible can be different in people with autism. For example, genes like SHANK3 and NRXN1 are important for synaptic strength. Changes in these genes can disrupt the balance of LTP and LTD, affecting how neurons communicate (Durand et al., 2007; Südhof, 2008) (Frontiers) (Nature).
Role of Dopamine:
- Dopamine is a chemical in the brain that helps regulate mood and movement. It also affects LTP and LTD. In autism, dopamine might not work the same way, influencing learning and behavior (Yagishita et al., 2014) (Frontiers).
Understanding these differences helps scientists find better ways to support autistics, aiming to improve learning, memory, and coordination.
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PlainSpeak. Plain Language for the Lay Reader
For the Academic/Scientific Audience
Remembering Judy. We miss you.
Remembering Judy who passed away a year ago this day. We miss you.
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Back in 2019 I had the opportunity to interview the legendary disability civil rights activist, Judy Heumann, for UC Berkeley's "The Daily Californian". Post: https://uniquelyhari.blogspot.com/2022/12/collaboration-cooperation.html
Other posts on Judy in this blog can be found at https://uniquelyhari.blogspot.com/search?q=heumann
Interoception
Interoception refers to the perception of internal bodily states and is a critical component of emotional awareness and regulation. In autism, interoceptive experiences can be distinct, potentially influencing the recognition and communication of needs and emotions (Quattrocki & Friston, 2014). This divergence in interoceptive processing underscores the complexity of understanding internal states and managing emotions in autism.
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