My events this April include
- Keynote at Duke's ACE event (Apr 3)
- TedX talk (Apr 20)
- Two Panels Mar 27 (Mary Ann Libert) & Apr 17 (Lancet).
My events this April include
Wright, P., Moseley, R., Tomasulo, D., Srinivasan, H., Wilson, J., Woods, S., & Rashid, T. (2024). Integrating Positive Psychology and Autism: A Roundtable. Autism in Adulthood.
Wright, Patricia, Rachel Moseley, Dan Tomasulo, Hari Srinivasan, Jodie Wilson, Sara Woods, and Tayyab Rashid. "Integrating Positive Psychology and Autism: A Roundtable." Autism in Adulthood (2024).
Wright, P., Moseley, R., Tomasulo, D., Srinivasan, H., Wilson, J., Woods, S. and Rashid, T., 2024. Integrating Positive Psychology and Autism: A Roundtable. Autism in Adulthood.
Wright P, Moseley R, Tomasulo D, Srinivasan H, Wilson J, Woods S, Rashid T. Integrating Positive Psychology and Autism: A Roundtable. Autism in Adulthood. 2024 Aug 14
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.
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.
Recent findings highlight several key aspects of PV+ cell hypofunction in autism:
PV INs are the most prevalent IN subtype in the cortex, but this does not exclude the possibility that other IN subtypes are involved.
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.
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).
PV+ neurons are crucial for modulating the tuning of Pyr neurons in the primary visual cortex (V1), thereby improving visual discrimination.
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).
2 Versions of this Post
For the Science/Academic Reader
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.
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.
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.
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.
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:
Examples of Slow Updating 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:
Examples of High-Precision Theories:
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.
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.
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.
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.
versions of this post
For the Scientific/Academic Audience