Cytokine-mediated tuning of neural circuits underlying avoidance behavior

Neuropsychiatric disorders, prevalent in nearly half of the U.S. population over a lifetime, are increasingly linked to immune dysregulation. Among these, allergic inflammation has emerged as a key contributor, highlighting an understudied connection between the immune system and mental health. Animal models reveal a causal relationship between allergic inflammation and heightened avoidance behaviors, a core symptom of mood and anxiety disorders. Unlike predominantly studied bacterial or viral immune challenges, allergic inflammation represents a distinct T helper cell type 2 (TH2)-mediated response triggered by nonpathogenic environmental stimuli, which activates emotion-related brain centers, including the medial prefrontal cortex (mPFC) and basolateral amygdala (BLA). These regions are critical for regulating social and anxiety-like behaviors. Converging evidence positions interleukin-4 (IL-4), a key TH2 cytokine elevated during allergic inflammation, as a potential modulator of mPFC circuits and their projections to the BLA, driving avoidance behaviors. This project seeks to determine how IL-4 impacts mPFC dynamics and contributes to heightened avoidance during allergic inflammation. In Aim 1, we will investigate the quantitative relationship between mPFC IL-4 and avoidance behavior during allergic inflammation, identify local IL-4-producing cell types, and determine the impact of heightened mPFC IL-4 on mPFC-BLA responses during avoidance. In Aim 2, we will examine how IL-4 modulates mPFC microcircuit activity and alters mPFC-BLA output and its contributions to allergic inflammation-induced neuroadaptations, defining its role as a non-classical neuromodulator. In Aim 3, we will test the necessity of mPFC IL-4Rα in allergic inflammation-associated mPFC-BLA responses and avoidance behaviors. By integrating advanced molecular, cellular, and circuit-level approaches, this research will uncover novel cytokine-driven mechanisms underlying behaviors associated with neuropsychiatric disorders and identify new immune-based therapeutic targets to address these complex disorders. Project Number: 1R01MH139476-01A1 | Fiscal Year: 2026 | NIH Institute/Center: National Institute of Mental Health (NIMH) | Principal Investigator: Reesha Patel | Institution: NORTHWESTERN UNIVERSITY, CHICAGO, IL | Award Amount: $708,139 | Activity Code: R01 | Study Section: Behavioral Neuroendocrinology, Neuroimmunology, Rhythms, and Sleep Study Section [BNRS] View on NIH RePORTER: https://reporter.nih.gov/project-details/11292555