Repeated Stress Escalates Aggression and Activity in Fronto‐Limbic Regions in <i> Cntnap2 ⁻ / ⁻ </i> Mice

Autism spectrum disorder (ASD) is characterized by social impairments and stereotyped behavior, with some individuals exhibiting heightened aggression in response to stress. This stress induced aggression (SIA) can severely impact quality of life, yet its underlying neural mechanisms remain poorly understood. Here, we investigated the behavioral phenotypes and neural activity that result as a consequence of stress in Cntnap2^-/-:TRAP2^+/-:Ai14^+/- mice. Deletion of the CNTNAP2 gene leads to a highly penetrant syndromic form of ASD, and the targeted recombination in active populations (TRAP) system allows for permanent access to neuronal populations activated during a specific experience, such as stress and aggression. We implemented a behavioral paradigm consisting of a baseline resident intruder assay, with either a single day or four consecutive days of restraint stress, followed by a posttest resident intruder assay in Cntnap2^-/-:TRAP2^+/-:Ai14^+/- and control mice. While a single day of restraint stress failed to induce changes in aggressive behavior in either genotype, 4 days of restraint stress significantly escalated aggression and reduced latency to attack selectively in Cntnap2^-/- mice. Using TRAP-based labeling, we observed increased neuronal activity in the lateral septum, lateral habenula, lateral hypothalamus, nucleus accumbens, and prelimbic cortex of Cntnap2^-/- mice. Interestingly, time aggressive and aggressive events were positively correlated with activity in the lateral septum, lateral habenula, and infralimbic cortex. These findings suggest that repeated stress engages specific fronto-striatal and limbic regions in Cntnap2^-/- mice and provide insight into the neural substrates of maladaptive SIA, offering a foundation for targeted therapeutic strategies.