Summary: Scientists at Stanford have identified excessive activity in the reticular thalamic nucleus (RT) as a driver of autism-like behaviors in a mouse model. The RT, a key regulator of sensory signals between the thalamus and cortex, became overactive during sensory stimulation and social encounters, producing seizures, repetitive actions, heightened sensory responses, and reduced social interaction. Suppressing RT hyperactivity with pharmacological and chemogenetic approaches reversed those behaviors, pointing to a shared brain mechanism between autism and epilepsy and suggesting a promising therapeutic target.
Using genetically modified Cntnap2 knockout mice that model core features of autism spectrum disorder (ASD), researchers recorded RT neural activity while monitoring behavior. They observed that RT neurons displayed increased burst firing and stronger intrathalamic oscillations, and that population activity in RT rose during exposure to stimuli (such as light or an air puff) and during social interactions. These abnormal activity patterns were associated with higher seizure susceptibility, hyperactivity, repetitive behaviors, and social withdrawal in the mice.
The team tested two independent strategies to reduce RT excitability. First, they administered Z944, an experimental blocker of T-type calcium channels that is under investigation for seizure control. Z944 lowered RT excitability and significantly improved autism-like behaviors in the mouse model. Second, they used a chemogenetic approach—designer receptors exclusively activated by designer drugs (DREADDs)—to selectively silence RT neurons. Activation of the inhibitory DREADD hM4Di by its ligand C21 similarly dampened RT activity and rescued behavioral deficits.
To confirm causality, researchers also increased RT activity in otherwise normal mice and reproduced several autism-related behaviors, demonstrating that RT hyperexcitability is sufficient to induce those deficits. Together, the pharmacological suppression, chemogenetic inhibition, and activity-enhancement experiments establish RT hyperexcitability as a mechanistic driver of the observed behaviors in this model.
These findings also help explain the high comorbidity between ASD and epilepsy. People with autism are far more likely to develop epilepsy than the general population, and this study highlights how shared alterations in thalamic circuitry—specifically RT hyperexcitability and elevated T-type calcium currents—could underlie both seizure susceptibility and autism-related symptoms.
The research was led by senior author John Huguenard, PhD, professor of neurology and neurological sciences, with Sung-Soo Jang, PhD, serving as lead author. The full report is scheduled for publication in Science Advances.
Methodologically, the team combined electrophysiology, in vivo fiber photometry, behavioral assays, pharmacology, and chemogenetics to link cellular and circuit-level changes in the RT to measurable behavioral outcomes. Electrophysiological recordings revealed strengthened T-type calcium currents and increased burst firing in RT neurons of Cntnap2−/− mice, while fiber photometry showed that RT population activity rose in association with sensory and social events.
By targeting RT excitability, both pharmacologically with a T-type channel blocker and chemogenetically with inhibitory DREADDs, the researchers achieved robust behavioral improvement. This convergence of evidence identifies the RT as a novel, tractable target for therapeutic development aimed at alleviating multiple ASD-related features, including sensory hypersensitivity, repetitive behavior, social deficits, and seizure vulnerability.
About this autism and neuropharmacology research news
Author: Bruce Goldman
Source: Stanford
Contact: Bruce Goldman – Stanford
Image: The image is credited to Neuroscience News
Original Research: Open access. “Reticular Thalamic Hyperexcitability Drives Autism Spectrum Disorder Behaviors in the Cntnap2 Model of Autism” by Sung-Soo Jang et al., published in Science Advances.
Abstract
Reticular Thalamic Hyperexcitability Drives Autism Spectrum Disorder Behaviors in the Cntnap2 Model of Autism
Autism spectrum disorders (ASDs) are neurodevelopmental conditions marked by social communication challenges, repetitive behaviors, and common comorbidities such as sensory processing differences, sleep problems, and seizures. While dysfunction in thalamocortical circuits has been implicated in these features, the specific contribution of the reticular thalamic nucleus (RT)—a major modulator of thalamocortical signaling—has been unclear.
Using the Cntnap2 knockout mouse model, the study shows that RT neurons exhibit hyperexcitability, increased burst firing, and elevated T-type calcium currents, alongside behavior-associated increases in RT population activity. Pharmacological blockade of T-type channels with Z944 and chemogenetic suppression through inhibitory DREADDs both improved ASD-related behaviors, including seizure susceptibility, hyperactivity, repetitive actions, sensory hypersensitivity, and social deficits. These results identify RT hyperexcitability as a mechanistic driver of ASD-like behaviors in this model and position the RT as a promising target for therapeutic intervention.