Summary: A new assay has been developed to measure how mice respond to social touch, allowing scientists to study reactions to social touch in animal models of autism. The test involves fixing a “test” mouse’s head in place while allowing it to run on a plastic foam ball, then bringing it face-to-face with either an inanimate object or a head-fixed “visitor” mouse. The researchers found that mice have a wide array of social-touch behaviors, with face-to-face interactions resembling how humans communicate. The assay provides a way to tackle complex behaviors that may not be possible with freely moving assays. With the ability to track movement direction, speed, facial expressions, and other responses, researchers can look for signs of apprehension and evasion during social touch. The assay has the potential to be used for cross-species comparisons of social touch and to track social-touch responses over time, pinpointing when aversion to social touch emerges in mouse models of autism.
In their study, the researchers focused on two mouse models of autism: one with the FMR1 gene missing, emulating fragile X syndrome, and one exposed to a maternal immune response in utero. Tactile defensiveness, a common trait among people with autism, was observed in both mouse models. Control mice tolerated social interactions with visitor mice, but both mouse models of autism tried to avoid social contact, exhibited signs of stress, and showed a longer-lasting pupil dilation, indicating heightened arousal.
The testing rig used in this assay is commercially available and relatively simple to set up and operate. It can be used in conjunction with calcium imaging or electrophysiological recording, allowing researchers to study neural activity alongside social-touch responses. The researchers are also exploring the possibility of increasing natural behavior in the assay by allowing the test mouse to control the motorized platform itself.
This assay provides a valuable tool for studying social touch in animal models of autism and has the potential for widespread use in various research settings.
– Journal of Neuroscience, doi: https://doi.org/10.53053/KSDN1910