Summary: A new study shows that environment significantly affects social behavior in zebrafish carrying a mutation linked to autism. In stressful, white Styrofoam tanks, the fish displayed higher anxiety and less social contact, while in familiar Plexiglass tanks their sociability improved.
Brain mapping revealed altered neural activity and sensory pathway abnormalities tied to vision, explaining the heightened anxiety in threatening environments. These findings suggest that environment-based interventions could offer new therapeutic approaches for autism.
Key Facts
- Environmental Impact: Zebrafish with autism-related mutation showed better sociability in familiar settings.
- Neural Mechanisms: Brain mapping revealed altered activity in sensory pathways tied to vision.
- Therapeutic Potential: Results suggest environment adjustments may help improve ASD-related social challenges.
Source: Niigata University
Researchers from Brain Research Institute, Niigata University, Japan have revealed that environment influences social behaviours in autism.
By using zebrafish that have a mutation in ube3a, a gene linked to Angelman Syndrome (AS) and autism spectrum disorders (ASD), they demonstrated that sensory processing of environmental information is determinant in the outcome of socializing or not.
The findings suggest that environmental adjustment could hold therapeutic potential in ASD.
ASD is characterized by difficulties in social interaction and repetitive behaviours. While genetics are known to play an important role, environmental influences are increasingly recognized as crucial modulators of behaviors. Nevertheless, the interactions between environment and genetic predispositions remains largely underexplored.
The team of researchers then used zebrafish carrying a point mutation in the ube3a gene—which shares similarities with AS and ASD—in order to investigate how deep environment affects social behaviours. Social behaviours were investigated in both a custom-made white Styrofoam and a Plexiglass tank environment, alongside conventional anxiety-related tests.
Neural activity mapping pre- and post- social interactions, and RNA sequencing were further conducted to uncover underlying mechanisms.
The zebrafish have an aversion to white colours and the Styrofoam environment was designed in white to manipulate their sense of anxiety and stress; at the opposite, the Plexiglass was made similar to the fish breeding tanks, thus appeared more familiar and safer.
In an interview, first author Dr Godfried Dougnon, Assistant Professor at the Department of Neuroscience of Disease, Brain Research Institute at Niigata University said: “ube3a mutant zebrafish displayed less time spent in contact to their conspecifics and higher anxiety levels in the stressful Styrofoam container, but these behaviours improved when the test was conducted in a preferred acrylic tank”.
He went on to explain that additional behavioral tests further confirmed higher anxiety-like responses in the mutants.
“Brain activity mapping using c-Fos in situ hybridization showed altered neural activity in specific brain regions, and transcriptomic analysis revealed increased expression of genes related to vision and its comorbidities, as well as abnormalities in sensory pathways”, said senior author Dr Hideaki Matsui, Professor at the same department.
This suggests that abnormal processing of visual information leads to elevated anxiety levels and reduced social interaction in threatening environments, behaviours that are improved in a more familiar setting.
Prof. Hideaki Matsui went on to conclude that: “These findings are important because they provide new clues for approaches to autism, and moreover, they are intriguing in that they suggest that conditions often thought to be uniquely human, such as autism-like disorders, may also exist in fish”.
This study demonstrates that social behavior could be affected by environment in individuals with ASD-related genetic predispositions.
These results open new therapeutic perspectives, indicating that tailoring environmental stimuli could maybe help improve some ASD-related behavioural challenges.
Future work will aim to translate these findings into human, and develop environment-based intervention strategies.
About this Autism research news
Author: Hideaki Matsui
Source: Niigata University
Contact: Hideaki Matsui – Niigata University
Image: The image is credited to Neuroscience News
Original Research: Closed access.
“Environmental context modulates sociability in ube3a zebrafish mutants via alterations in sensory pathways” by Godfried Dougnon et al. Molecular Psychiatry
Abstract
Environmental context modulates sociability in ube3a zebrafish mutants via alterations in sensory pathways
Individuals with autism spectrum disorder (ASD) have a greater prevalence of deficits in social interactions and repetitive behaviours, which are influenced by hereditary and environmental factors. How environmental factors influence genetically predisposed individuals remains unknown.
Here, we provide new evidence of the interplay between social behaviour and environmental influences, by manipulating perceived safety and threat levels in ube3a mutant zebrafish, a mutation that is linked to Angelman syndrome and ASD.
Mutant fish demonstrated abnormal social behaviour in an aversive custom-made Styrofoam container, whereas these abnormalities ameliorated in a preferred Plexiglass setting.
Our findings were further supported by elevated anxiety levels in the mutants when they performed conventional anxiety-related tests, such as the light‒dark test (LDT) and the novel tank diving test (NTT).
Additionally, neural activity mapping using c-Fos in situ hybridization revealed differences in activation patterns in the brains of the mutants. Importantly, we performed an overrepresentation analysis (ORA) using RNA sequencing data from ube3a mutants and integrating datasets from human diseases.
We identified the upregulation of vision- and comorbidity-related genes in ube3a mutants and alterations in sensory pathways, highlighting that abnormal processing of visual information is the cause of increased anxiety levels, resulting in decreased social interaction in a stressful Styrofoam environment.
Our findings underscore the crucial impact of environmental factors on social behaviour and indicate that therapeutic options for ASD that focus on adjusting environmental contexts to modify perceived stimuli may ameliorate ASD-like behaviours.
