Neurobiologists have provided a new understanding of the origin of environmentally triggered autistic behavior. Credit Spitzer Lab, UC San Diego

Autism involve mild to severe impairment of social, behavioral and communication abilities. These disorders can significantly impact performance at school, in employment and in other areas of life. However, researchers lack knowledge about how these disorders emerge at early stages of development.

University of California San Diego neurobiologists have found evidence of altered development of the nervous system in mouse models of autism spectrum disorders. They linked environmentally induced forms of autism to changes in neurotransmitters, the chemical messengers that allow neurons to communicate with each other. They also discovered that manipulating these neurotransmitters at early stages of development can prevent the appearance of autistic-like behaviors.

“In seeking the root causes of autism spectrum disorder behaviors in the brain, we found an early change in neurotransmitters that is a good candidate to be the primary cause,” said School of Biological Sciences Professor Nicholas Spitzer of the Department of Neurobiology and Kavli Institute for Brain and Mind. “Getting a handle on the early events that trigger autism may allow development of new forms of intervention to prevent the appearance of these behaviors.”

Autism diagnoses have been ramping up in recent years, but how these disorders manifest at the critical cellular and molecular levels has not been well understood.

The study’s lead author, Assistant Project Scientist Swetha Godavarthi, and colleagues investigated neurotransmitter expression in the medial prefrontal cortex, a brain area often affected in individuals diagnosed with autism. They tested the hypothesis that changes in the type of neurotransmitter expressed by neurons in the prefrontal cortex could be responsible for a chemical imbalance that causes autism-like behaviors.

Previous studies had shown an increase in the incidence of autism in offspring when pregnant women had a heightened immune response or were exposed to certain drugs during the first trimester (environmental forms of autism ). The researchers reproduced autism in mice by administering mice in utero with these environmental agents. These agents caused the brief loss of the “GABA” neurotransmitter, which is inhibitory, and the gain of the “glutamate” neurotransmitter, which is excitatory, in neonatal mice. Although this GABA-to-glutamate transmitter switch reversed spontaneously after a few weeks, adult mice exhibited altered behaviors of repetitive grooming and diminished social interaction. Overriding this brief early transmitter switch in neonatal mice prevented the development of these autistic-like behaviors in adults.

“Driving expression of GABA in the neurons that have replaced GABA with glutamate prevents the appearance of stereotyped repetitive behavior and reduced social interaction,” said Spitzer. “These findings demonstrate that changing electrical activity and inappropriately exciting neurons at early stages of development can alter the assembly of the nervous system.”

Alterations in neurotransmitter expression at an early stage of development carry implications for other behavioral issues at later stages in life, since the rest of the nervous system is then built upon a platform of defective wiring, similar to a house constructed on an unstable foundation.

“Neurotransmitter switching can change the assembly of the nervous system and have a profound impact downstream,” said Spitzer.

The researchers say the new results are consistent with other evidence that altering signaling in the nervous system during the early stages of development can later carry negative consequences as the brain matures.

The authors discovered that newspapers portrayed autism more positively when it was associated with a specific person rather than discussed in general terms. Additionally, using identity-first language (e.g., ‘autistic person’) was associated with more positive sentiments than using person-first language (e.g., ‘person with autism’).

While broadsheets portrayed autistic individuals more positively than tabloids did, no distinction was found between left-leaning and right-leaning papers.

The research, published in the journal Autism in Adulthood, suggests that newspapers should portray autistic people in a more positive light. This is crucial because newspapers significantly impact public perceptions of autistic individuals.

Media portrayals

Newspapers frequently depict autistic individuals in a negative and stereotypical manner, focusing on their difficulties and limitations rather than their unique abilities and requirements. Media sources also often use language that does not acknowledge the preferred way autistic individuals want to be described. This type of language adversely affects the mental well-being of autistic individuals and impairs their acceptance in society.

To gain insight into the portrayal of autistic individuals in British newspapers, researchers enlisted the perspectives of five autistic individuals to evaluate the sentiment towards autism and autistic people in 1,000 quotations from British newspapers spanning from 2011 to 2020.

The researchers asked autistic experts to assess how newspapers talked about autistic people without telling them the newspaper’s name or when the article was published. The experts judged the articles based on how warmly the newspapers talked about autistic people and how competent they made them seem. The researchers then looked at the overall judgments of warmth and competence. They looked at how the language and terminology varied, such as using general or impersonal language to talk about autism, and whether the newspapers used identity-first or person-first language. They also checked for differences between different types of newspapers and whether there were changes over time.

Study findings

The majority of quotes from British newspapers were found to have low levels of warmth and competence. Additionally, impersonal references to autism tended to receive lower ratings in warmth and competence compared to references linking autism to a person. Meanwhile, language that prioritizes identity first was rated higher in warmth and competence than language that prioritizes person first.

Although quotes from broadsheets and tabloids were rated similarly in warmth, the former were deemed slightly more competent. No significant differences were found in terms of warmth and competence between left-leaning and right-leaning papers.

The study also observed inconsistent changes over time. Newspaper portrayals shifted towards more positive representations between 2015 and 2017, but became more negative between 2018 and 2020.

“The media’s coverage of autism has grown in recent years, and the concept of neurodiversity is gaining recognition in educational and professional settings. Some recent studies suggest a small but noticeable shift towards more positive attitudes towards autism in public discussions.”

The new study challenges the idea that media coverage of autism has improved over time, based on the perceptions of autistic people. The study found that newspapers still often cover stories about the so-called ‘cure’ or ‘reversal’ of autism, which can be hurtful and offensive to the autism community.

“Our study emphasizes the vital role of language and terminology for autistic individuals. It is important for autistic individuals to have a say in shaping more inclusive media coverage. Newspapers must also respect the language preferences of the autistic community. Our study provides both positive and negative examples of autism coverage, which can help facilitate this shift.”