- Active Sensing
- Alexithymia
- Apraxia
- Asset Framing
- Attribution Errors
- Autistic Burnout
- Autistic Inertia
- Blindsight
- Body Schema
- Camoflauging
- Catatonia
- Cocktail Party Effect
- Cognitive Dissonance Theory
- Depersonalization
- Double Empathy Problem
- Dyspraxia
- ECCT - Executive and Contextual Control Theory
- E-I Imbalance Theory
- EPF - Enhanced Perceptual Functioning Model
- ES Theory of Autism
- Executive Dysfunction Theory
- Exteroception
- Flat Effect
- Fluid & Crystallized Intelligence
- Hostile Attribution Bias
- Implicit and Explicit Bias
- Intense World Theory
- Interoception
- Linear & Non Linear Thinking
- Local and Distributed Information
- Lucid Dreaming
- Masking
- Mental Age
- Mental Time Travel
- Monotropism
- Multiple Intelligences
- Neuronal Pruning Theory
- Negative Attribution Bias
- Neuroception
- Peripersonal Space (My area of research)
- Predictive Coding Theories
- Predictive Homeostatis Theory
- Propagnosia
- PV Neuron Hypothesis
- Sensory Processing (see #Sensorimotor)
- Social Motivation Theory
- Special Interests (SPIN)
- Spoon Theory
- Stimming
- Synesthesia
- Temporal Binding Window
- Theory of Mind
- Triple Bind and Masking
- Weak Central Coherence Theory
Cognitive Theories and Sensorimotor Explanations for Autism
While no single theory or idea fully explains all aspects of autism, each attempts to provide insights into different cognitive, sensory or behavioral characteristics associated with autism or the history behind why things could be the way they are. Here are some of the theories, ideas and issues. they can also be found in posts in the following hashtags [#sensorimotor] [#AutismTheories]
PV hypothesis of autism
Background and Rationale
The Parvalbumin (PV) hypothesis of autism proposes that dysfunction in PV-expressing interneurons (INs) underlies many of the core features of autism. Despite the heterogeneity in genetic and environmental factors contributing to autism, there is a remarkable similarity in the atypical behaviors observed, suggesting a common pathophysiology across brain regions (Contractor et al., 2021).
The Parvalbumin hypothesis of autism underscores the critical role of PV+ interneurons in maintaining neural circuit balance. Their dysfunction leads to various neurological and behavioral abnormalities observed in autism, such as sensory hypersensitivity and seizures.
Evolution of the E/I Imbalance Theory
Initially, the theory of excitation/inhibition (E/I) imbalance was proposed, suggesting that reduced GABAergic inhibition leads to an increased E/I ratio, which correlates with delayed cortical maturation in autism (Hussman, 2001; Rubenstein & Merzenich, 2003). This model explains the co-occurrence of seizures in autism but has limitations due to the involvement of various cell types in regulating E/I balance, making it difficult to identify specific therapeutic targets. A more nuanced approach involves examining different IN subtypes under behaviorally relevant brain states.
Evidence for PV+ Cell Hypofunction in Autism
Recent findings highlight several key aspects of PV+ cell hypofunction in autism:
- Reduced density of PV INs: Lower expression of PV protein and decreased density of perineuronal nets (PNNs) around INs.
- Increased power of baseline gamma oscillations: Gamma oscillations, regulated by PV and somatostatin (SST) INs, show increased power in autism.
- Decreased activity of PV INs: Reduced visually-evoked activity in PV INs.
PV INs are the most prevalent IN subtype in the cortex, but this does not exclude the possibility that other IN subtypes are involved.
Hyperexcitability and Hypersynchrony
PV hypofunction leads to hyperexcitability and hypersynchrony, predisposing individuals to seizures and exaggerated sensory-evoked responses in pyramidal (Pyr) neurons of sensory cortices. For instance, whisker-evoked responses are suppressed in Layer 2/3 neurons of the primary somatosensory cortex (S1) in Fmr1 knockout (KO) mice, a model of autism.
Sensory Hypersensitivity
A failure of neurons to adapt to ongoing stimulation, observed in Fmr1 KO mice and autistic humans, may contribute to sensory hypersensitivity. This lack of neuronal adaptation can prevent individuals from tuning out irrelevant stimuli (Green et al., 2015).
Role of PV+ Neurons in Visual Processing
PV+ neurons are crucial for modulating the tuning of Pyr neurons in the primary visual cortex (V1), thereby improving visual discrimination.
Gamma Oscillations and Other Brain Rhythms
Increased power of resting-state gamma band oscillatory activity (> 30 Hz) is associated with sensory processing and communication deficits in autism and fragile X syndrome (FXS). PV INs are critical in generating gamma rhythms. PV hypofunction, as seen after PV cell-specific deletion of the NR1 subunit of NMDA-type glutamate receptors, results in increased broadband gamma power due to decreased synchronicity (Guyon et al., 2021).
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For the Science/Academic Reader
References
- Contractor, A., Klyachko, V. A., & Portera-Cailliau, C. (2021). Reduced density and activity of parvalbumin interneurons in autism. Journal of Neurodevelopmental Disorders, 13(1), 1-15.
- Green, S. A., & Gu, Y. (2015). Sensory hypersensitivity in autism spectrum disorders. Current Biology, 25(18), R876-R879.
- Guyon, N., & Nahmani, M. (2021). Role of parvalbumin interneurons in gamma oscillations and sensory processing in autism. Frontiers in Neuroscience, 15, 692872.
- Hussman, J. P. (2001). Suppressed GABAergic inhibition as a common factor in suspected etiologies of autism. Journal of Autism and Developmental Disorders, 31(2), 247-248.
- Rubenstein, J. L., & Merzenich, M. M. (2003). Model of autism: Increased ratio of excitation/inhibition in key neural systems. Genes, Brain and Behavior, 2(5), 255-267.
Keynote Speaker at Duke
My Keynote for Autism Month at Duke.
Registration at.
https://duke.zoom.us/meeting/register/tJcrdeqorDIpHdRE-CRvLPHkzKdL_ta7eYq-#/registration
Autism Acceptance Month Keynote Presentation: "Redefine the Table"
April 3, 2024 | 4:00pm - 5:00pm ET
Zoom Webinar
Please join us for a special event in our 2023-24 Duke Center for Autism Seminar Series! Our Autism Acceptance Month Keynote presenter will be Hari Srinivasan. A self-advocate, Mr. Srinivasan is a PhD student in neuroscience at Vanderbilt University, an alumnus of the University of California, Berkeley, a Paul & Daisy Soros Fellow, a NISE fellow at the Frist Center for Autism & Innovation at Vanderbilt University, and a public member of the Interagency Autism Coordinating Committee. At UC Berkeley, Mr. Srinivasan majored in psychology with a minor in disability studies and graduated as a University Medal Finalist, along with a Departmental Citation Award, Highest Honors, Phi Beta Kappa, and Psi Chi. He was an undergraduate Haas Scholar and carried out a year-long study on awe and empathy in autism. He was also lead student instructor for a weekly class on autism, creating and teaching content that covered a myriad of issues across the lifespan. As a student journalist at The Daily Californian, he wrote over 50 articles on both disability and non-disability topics. As part of his graduate program, he will research the sensorimotor space, specifically peripersonal space (PPS), which has practical implications on multiple fronts for autism. He has autism and ADHD. His autism includes limited speaking ability, sensorimotor issues, health issues, OCD, mood dysregulation and social anxiety. His non-academic affiliations span law and policy to research arenas such as IACC, DREDF, ASAN, ASA, INSAR, Autism Europe and The Brain Foundation. PLEASE REGISTER IN ADVANCE AT THE LINK PROVIDED.
Speaker(s): Hari Srinivasan
Duke Event Series: Duke Center for Autism Seminar Series
Duke Event Co-Sponsor(s): Duke Center for Autism and Brain Development, Department of Psychiatry and Behavioral Sciences, Duke Global Health Institute (DGHI), Duke Institute for Brain Sciences (DIBS)
Duke Event Type(s): Diversity/Inclusion, Lecture/Talk, Webcast
Autism Acceptance Month 2024
Our keynote for Autism Acceptance Month 2024 will be Hari Srinivasan, presenting "Redefine the Table."
Our keynote presenter for Autism Acceptance Month 2024 will be Hari Srinivasan. A self-advocate, Mr. Srinivasan is a PhD student in neuroscience at Vanderbilt University, an alumnus of the University of California, Berkeley, a Paul & Daisy Soros Fellow, a NISE fellow at the Frist Center for Autism & Innovation at Vanderbilt University, and a public member of the Interagency Autism Coordinating Committee.
At UC Berkeley, Mr. Srinivasan majored in psychology with a minor in disability studies and graduated as a University Medal Finalist, along with a Departmental Citation Award, Highest Honors, Phi Beta Kappa, and Psi Chi. He was an undergraduate Haas Scholar and carried out a year-long study on awe and empathy in autism. He was also lead student instructor for a weekly class on autism, creating and teaching content that covered a myriad of issues across the lifespan. As a student journalist at The Daily Californian, he wrote over 50 articles on both disability and non-disability topics.
As part of his graduate program, he will research the sensorimotor space, specifically peripersonal space (PPS), which has practical implications on multiple fronts for autism. He has autism and ADHD. His autism includes limited speaking ability, sensorimotor issues, health issues, OCD, mood dysregulation and social anxiety. His non-academic affiliations span law and policy to research arenas such as IACC, DREDF, ASAN, ASA, INSAR, Autism Europe and The Brain Foundation.
VR Research Cave
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I'm going to get to use this cool tech in my research design to study sensorimotor issues in autism.
Processing loss and grief is even more intense for autistics.
Another excellent and deep article from Hari Srinivasan about how loneliness, lack of support, disruption in schedules and being the child of immigrants, can make processing loss and grief even more intense for autistic people.
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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